1<?xml version='1.0' encoding='us-ascii'?>
2<!DOCTYPE rfc SYSTEM "rfc2629.dtd">
3
4<rfc submissionType="IETF" category="std" consensus="yes" number='8383'>
5  <?rfc compact="yes"?>
6 <?rfc text-list-symbols="-o*+"?>
7 <?rfc subcompact="no"?>
8 <?rfc sortrefs="yes"?>
9 <?rfc symrefs="yes"?>
10 <?rfc strict="yes"?>
11 <?rfc toc="yes"?>
12 <front>
13   <title abbrev="TRILL Address Flush Message">Transparent Interconnection of Lots of Links (TRILL): Address&nbsp;Flush&nbsp;Message</title>
14   
15   <author fullname="Weiguo Hao" initials="W." surname="Hao">
16     
17 <organization abbrev="Huawei">Huawei Technologies</organization>
18 <address><postal><street>101 Software Avenue,</street>
19 <street>Nanjing 210012</street>
20 <street>China</street>
21 </postal>
22 <phone>+86-25-56623144</phone>
23 <email>haoweiguo@huawei.com</email>
24 </address>
25   </author>
26   <author fullname="Donald Easlake 3rd" initials="D." surname="Eastlake, 3rd">
27     <organization abbrev="Huawei">Huawei Technologies</organization>
28     <address><postal><street>155 Beaver Street</street><street>Milford, MA 01757</street>
29     <street>United States of America</street></postal>
30     <phone>+1-508-333-2270</phone>
31     <email>d3e3e3@gmail.com</email>
32     </address>
33   </author>
34
35 <author fullname="Yizhou Li" initials="Y." surname="Li">
36 <organization abbrev="Huawei">Huawei Technologies</organization>
37 <address><postal><street>101 Software Avenue,</street>
38 <street>Nanjing 210012</street>
39 <street>China</street>
40 </postal>
41 <phone>+86-25-56624629</phone>
42 <email>liyizhou@huawei.com</email>
43 </address>
44 </author>
45
46 <author fullname="Mohammed Umair" initials="M." surname="Umair">
47 <organization>Cisco</organization>
48 <address><postal><street>Cessna Business Park, Kadubeesanahalli Village, Hobli,</street>
49 <street>Sarjapur, Varthur Main Road, Marathahalli,</street>
50 <street>Bengaluru, Karnataka 560087</street>
51 <street>India</street>
52 </postal>
53 <email>mohammed.umair2@gmail.com</email>
54 </address>
55 </author>
56
57 <date month="May" year="2018"/>
58 <workgroup>TRILL Working Group</workgroup>
59
60<!-- [rfced] Please insert any keywords (beyond those that appear in 
61the title) for use on https://www.rfc-editor.org/search.
62-->
63
64<keyword>example</keyword>
65
66<abstract>
67  <t> The TRILL (Transparent Interconnection of Lots
68 of Links) protocol, by default, learns end station addresses
69 from observing the data plane.  In particular, it learns local
70 Media Access Control (MAC) addresses and the edge switch port of
71 attachment from the receipt of local data frames and learns
72 remote MAC addresses and the edge switch port of attachment from the
73 decapsulation of remotely sourced TRILL Data packets.</t>
74
75 <t>
76   This document specifies a message by which a TRILL switch can
77   explicitly request other TRILL switches to flush certain MAC
78   reachability learned through the decapsulation of TRILL Data packets.
79
80   <!--[rfced] To what does "the TRILL automatic address forgetting" refer?  Will the reader understand this phrase?
81
82Original:
83   This is a supplement to the TRILL automatic address forgetting and
84   can assist in achieving more rapid convergence in case of topology or
85   configuration change.
86
87-->
88   This is a supplement to the TRILL automatic address forgetting and
89   can assist in achieving more rapid convergence in case of topology or
90   configuration change.</t>
91
92 </abstract>
93 </front>
94
95 <middle>
96 <section title="Introduction" anchor="section-1"><t>
97   By default, edge TRILL (Transparent Interconnection of Lots of Links) switches
98   <xref target="RFC6325"/> <xref target="RFC7780"/>, also called edge Routing Bridges (RBridges), learn end
99   station MAC address reachability from observing the data plane. On
100   receipt of a native frame from an end station, they would learn the
101   local MAC address attachment of the source end station. And on
102   egressing (decapsulating) a remotely originated TRILL Data packet,
103   they learn the remote MAC address and remote attachment TRILL switch.
104   Such learning is all scoped by data label (VLAN or Fine-Grained Label (FGL)
105   <xref target="RFC7172"/>).</t>
106
107 <t>
108   TRILL has mechanisms for timing out such learning and appropriately
109   clearing it based on some network connectivity and configuration
110   changes; however, there are circumstances under which it would be
111   helpful for a TRILL switch to be able to explicitly flush (purge)
112   certain learned end station reachability information in remote
113   RBridges to achieve more-rapid convergence.  Section 6.2 of <xref target="RFC4762"/>
114   is an example of the use of such a mechanism.</t>
115
116 <t>
117   Another example, based on Appendix A.3 of <xref target="RFC6325"/> ("Wiring Closet Topology"), presents a bridged LAN connected to a TRILL network via
118   multiple RBridge ports. For optimum paths, Appendix A.3.3 suggests
119   configuring the RBridge ports to be like one Spanning Tree Protocol
120   (STP) tree root in the bridged LAN. The address flush message in this
121   document could also be triggered in this case when one of the edge
122   RBridges receives Topology Change (TC) information (e.g., TC 
123   in STP, Topology Change Notification (TCN) in Multiple
124   Spanning Tree Protocol (MSTP) in order to rapidly flush the MAC addresses
125   for specific VLANs learned at the other edge RBridge ports.</t>
126
127 <t>
128   A TRILL switch can easily flush any locally learned addresses it
129   wants. This document specifies an RBridge Channel Support protocol <xref
130   target="RFC7178"/> message to request flushing address information
131   for specific VLANs or FGLs (<xref target="RFC7172"/>) learned from decapsulating TRILL Data
132   packets.</t>
133
134   <section title="Terminology and Abbreviations" anchor="section-1.1">
135
136     <t> The key words "MUST", "MUST NOT",
137 "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT",
138 "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to
139 be interpreted as described in <xref target="RFC2119"/> <xref
140 target="RFC8174"/> when, and only when, they appear in all
141 capitals, as shown here.</t>
142
143 <t>
144   This document uses the terms and abbreviations defined in <xref
145   target="RFC6325"/> and <xref target="RFC7978"/> as well as the
146   following:</t>
147
148 <t><list hangIndent="3" style="hanging"><t hangText="Data Label:">A VLAN or FGL</t>
149
150         <t hangText="Edge TRILL Switch:">A TRILL switch attached to one or more links that provide end station service
151 </t>
152
153      <t hangText="FCS:">Frame Check Sequence</t>
154
155      <t hangText="FGL:">Fine-Grained Label <xref target="RFC7172"/></t>
156
157<t hangText="Management VLAN:"> A VLAN in which all TRILL switches in a campus
158 indicate interest so that multi-destination TRILL Data packets,
159         including RBridge Channel messages <xref target="RFC7978"/>, sent with that
160         VLAN as the Inner.VLAN will be delivered to all TRILL switches
161         in the campus. Usually, no end station service is offered in the
162         Management VLAN.
163 </t>
164
165
166
167      <t hangText="MAC:">Media Access Control</t>
168
169      <t hangText="RBridge:">An alternative name for a TRILL switch</t>
170
171      <t hangText="STP:">Spanning Tree Protocol</t>
172
173      <t hangText="TC:">Topology Change message</t>
174
175      <t hangText="TCN:">Topology Change Notification message</t>
176
177<t hangText="TRILL switch:">A device implementing the TRILL protocol RFC 6235
178 <xref target="RFC7780"/>
179 </t>
180
181 </list>
182 </t>
183
184 </section>
185
186 </section>
187
188 <section title="Address Flush Message Details" anchor="section-2"><t>
189   The Address Flush message is an RBridge Channel protocol message
190   <xref target="RFC7178"/>.</t>
191
192 <t>
193   The general structure of an RBridge Channel packet on a link between
194   TRILL switches is shown in <xref target="ref-rbridge-channel-protocol-message-structure"/>. The Protocol field in the
195   RBridge Channel Header gives the type of RBridge Channel packet and
196   indicates how to interpret the Channel Protocol Specific Payload
197
198<!--[rfced] RFC 7178 does not use the specific term "Channel Protocol Specific Payload".  We note that RFC-to-be 8381 updated to use "Channel-Protocol-Specific Payload".  Please review the use of this term in this document and the other two and let us know if updates should be made.
199
200-->
201   <xref target="RFC7178"/>.
202
203
204
205 </t>
206<!--[rfced] We note that the content of Figure 1 is an exact replica
207of Figure 1 in RFC-to-be 8381.  Only the titles are different.
208Please confirm that this is intentional and no updates should be
209made.
210
211RFC 8381:
212RBridge Channel Packet Structure
213
214This document:
215RBridge Channel Protocol Message Structure
216
217-->
218
219<figure title="RBridge Channel Protocol Message Structure" anchor="ref-rbridge-channel-protocol-message-structure"><artwork><![CDATA[
220
221                   +-----------------------------------+
222                   |            Link Header            |
223                   +-----------------------------------+
224                   |            TRILL Header           |
225                   +-----------------------------------+
226                   |      Inner Ethernet Addresses     |
227                   +-----------------------------------+
228                   |      Data Label (VLAN or FGL)     |
229                   +-----------------------------------+
230                   |       RBridge Channel Header      |
231                   +-----------------------------------+
232                   | Channel Protocol Specific Payload |
233                   +-----------------------------------+
234                   |   Link Trailer (FCS if Ethernet)  |
235                   +-----------------------------------+
236]]></artwork>
237 </figure>
238
239 <t>
240   By default, an Address Flush RBridge Channel message applies to
241   addresses within the Data Label that appear right after the Inner
242   Ethernet Addresses.  Address Flush protocol messages are usually sent
243   as multi-destination packets (TRILL Header M bit equal to one) so as
244   to reach all TRILL switches offering end station service in the VLAN
245   or FGL specified by that Data Label. Both multi-destination and
246   unicast Address Flush messages SHOULD be sent at priority 6 since
247   they are important control messages but are lower priority than
248   control messages that establish or maintain adjacency.</t>
249
250 <t>
251   Nevertheless:</t>
252
253   <t><list style="symbols">
254
255     <t>There are provisions for optionally indicating the Data Label(s)
256      to be flushed for cases where the Address Flush message is sent
257      over a Management VLAN or the like.</t>
258
259 <t>An Address Flush message can be sent unicast, if it is desired to
260      clear addresses at one TRILL switch only.</t>
261
262 <t>An Address Flush message can be sent selectively to the RBridges
263      that have at least one access port configured as one of the VLANs or
264      FGLs specified in the Address Flush message payload.</t>
265
266 </list>
267 </t>
268
269 <t>
270   Implementations should consider logging address flush messages
271   received with appropriate protections against packet storms.</t>
272
273   <section title="VLAN Block Only Case" anchor="section-2.1">
274
275     <t>
276   <xref target="ref-address-flush-message-vlan-block-case"/> expands
277   the RBridge Channel Header and Channel Protocol Specific Payload
278   from <xref
279   target="ref-rbridge-channel-protocol-message-structure"/> for the
280   case of the VLAN-only-based Address Flush message. This form of the
281   Address Flush message is optimized for flushing MAC addresses based
282   on nickname and blocks of VLANs. 0x8946 is the Ethertype assigned
283     by IEEE for the RBridge Channel protocol.</t>
284
285<!--[rfced] Would a pointer to an IEEE registry be needed/wanted by the reader or others?  If so, please let us know how to update.
286
287Original:
288 0x8946 is the Ethertype assigned by IEEE for the RBridge Channel protocol
289
290-->
291
292 <figure title="Address Flush Message - VLAN Block Case" anchor="ref-address-flush-message-vlan-block-case"><artwork><![CDATA[
293    0                   1                   2                   3
294    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
295RBridge Channel Header:
296   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
297   |    RBridge-Channel (0x8946)   |  0x0  |Channel Protocol= 0x009|
298   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
299   |          Flags        |  ERR  |
300   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
301Address Flush Protocol Specific:
302   +-+-+-+-+-+-+-+-+
303   | K-nicks       |
304   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
305   | Nickname 1                    | Nickname 2                    |
306   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
307   | Nickname ...                  | Nickname K-nicks              |
308   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
309   | K-VLBs        |
310   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
311   | RESV  | Start.VLAN 1          | RESV  | End.VLAN 1            |
312   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
313   | RESV  | Start.VLAN 2          | RESV  | End.VLAN 2            |
314   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
315   | RESV  | Start.VLAN ...        | RESV  | End.VLAN ...          |
316   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
317   | RESV  | Start.VLAN K-VLBs     | RESV  | End.VLAN K-VLBs       |
318   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
319]]></artwork>
320 </figure>
321 <t>
322   The fields in <xref target="ref-address-flush-message-vlan-block-case"/> related to the Address Flush message are as
323   follows:</t>
324
325 <t><list style="hanging" hangIndent="3">
326 <t hangText="Channel Protocol:">
327 The RBridge Channel Protocol value allocated
328 for Address Flush (see <xref target="section-3"/>).
329 </t>
330
331 <t hangText="K-nicks:">The number of nicknames listed as an unsigned
332 integer. If this is zero, the ingress nickname in the TRILL
333         Header <xref target="RFC6325"/> is considered to be the only nickname to which
334         the message applies. If non-zero, it gives the number of
335         nicknames listed right after K-nicks to which the message
336         applies, and, in this non-zero case, the flush does not apply to
337         the ingress nickname in the TRILL Header unless it is also
338         listed. The message flushes address learning due to egressing
339         TRILL Data packets that had an ingress nickname to which the
340         message applies.
341 </t>
342
343 <t hangText="Nickname:">A listed nickname to which it is intended that the Address Flush message apply.  If an unknown or reserved
344         nickname occurs in the list, it is ignored, but the address
345         flush operation is still executed with the other nicknames. If
346         an incorrect nickname occurs in the list, so that some address
347         learning is flushed that should not have been flushed, the
348         network will still operate correctly; however, it will be less efficient
349         as the incorrectly flushed learning is relearned.
350 </t>
351
352 <t hangText="K-VLBs:">The number of VLAN blocks present as an unsigned
353 integer. If this byte is zero, the message is the more general
354         format specified in <xref target="section-2.2"/>. If it is non-zero, it gives
355         the number of blocks of VLANs present. Thus, in the VLAN Block
356         address flush case, K-VLBs will be at least one.
357 </t>
358
359 <t hangText="RESV:">4 reserved bits. MUST be sent as zero and ignored on
360 receipt.
361 </t>
362
363 <t hangText="Start.VLAN, End.VLAN:">These 12-bit fields give the beginning and
364 ending VLAN IDs of a block of VLANs. The block includes both
365         the starting and ending values; so, a block of size one is
366         indicated by setting End.VLAN equal to Start.VLAN. If
367         Start.VLAN is 0x000, it is treated as if it was 0x001. If
368         End.VLAN is 0xFFF, it is treated as if it was 0xFFE. If
369         End.VLAN is smaller than Start.VLAN, considering both as
370         unsigned integers, that VLAN block is ignored, but the address
371         flush operation is still executed with other VLAN blocks in the
372         message.  VLAN blocks may overlap, in which case, the address
373         flush operation is applicable to a VLAN covered by any one or
374         more of the blocks in the message.
375 </t>
376
377 </list>
378 </t>
379
380
381 <t>
382   This message flushes all addresses in an applicable VLAN learned from
383   egressing TRILL Data packets with an applicable nickname as ingress.
384   To flush addresses for all VLANs, it is easy to specify a block
385   covering all valid VLAN IDs (i.e., from 0x001 to 0xFFE).</t>
386
387 </section>
388
389 <section title="Extensible Case" anchor="section-2.2"><t>
390   A more general form of the Address Flush message is provided to
391   support flushing by FGL and more efficient encodings of VLANs and
392   FGLs where using a set of contiguous blocks is cumbersome. It also
393   supports optionally specifying the MAC addresses to clear. This form
394   is extensible.</t>
395
396 <t>
397   The extensible case is indicated by a zero in the byte shown in
398   <xref target="ref-address-flush-message-vlan-block-case"/> as "K-VLBs" followed by other information encoded as TLVs.</t>
399
400 <figure title="Address Flush Message - Extensible Case" anchor="ref-address-flush-message-extensible-case"><artwork><![CDATA[
401    0                   1                   2                   3
402    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
403RBridge Channel Header:
404   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
405   |    RBridge-Channel (0x8946)   |  0x0  |Channel Protocol=0x009 |
406   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
407   |          Flags        |  ERR  |
408   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
409Address Flush Protocol Specific:
410   +-+-+-+-+-+-+-+-+
411   | K-nicks       |
412   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
413   | Nickname 1                    | Nickname 2                    |
414   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
415   | Nickname ...                  | Nickname K-nicks              |
416   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
417   | 0             |  TLVs ...
418   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...
419]]></artwork>
420 </figure>
421
422 <t><list style="hanging" hangIndent="3"><t hangText="Channel Protocol, K-nicks, Nickname:">These fields are as specified
423 in <xref target="section-2.1"/>.
424 </t>
425
426 <t hangText="TLVs:">If the byte immediately before the TLVs field, which is the byte labeled "K-VLBs" in <xref target="ref-address-flush-message-vlan-block-case"/>, is zero, as shown in <xref target="ref-address-flush-message-extensible-case"/>, the remainder of the message consists of TLVs encoded as
427         shown in <xref target="ref-type-length-value"/>.
428 </t>
429
430 </list>
431 </t>
432
433
434
435 <figure title="Type, Length, Value" anchor="ref-type-length-value"><artwork><![CDATA[
436          0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
437         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
438         |  Type         |  Length       |  Value
439         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
440]]></artwork>
441 </figure>
442
443 <t><list style="hanging" hangIndent="3"><t hangText="Type:">The 8-bit TLV type as shown in the table below. See
444 subsections of <xref target="section-2.2"/> for details on each type
445         assigned below. If the type is reserved or not known by a
446         receiving RBridge, that receiving RBridge ignores the value and
447         skips to the next TLV by use of the Length byte. There is no
448         provision for a list of VLAN ID TLVs as there are few enough of
449         them that an arbitrary subset of VLAN IDs can be represented as
450         a bit map.
451 </t>
452
453 </list>
454 </t>
455
456
457 <figure><artwork><![CDATA[
458             Type       Description       Reference
459            ------   ------------------  -----------------
460                0     Reserved            [RFC8383]
461                1     Blocks of VLANs     [RFC8383]
462                2     Bit Map of VLANs    [RFC8383]
463                3     Blocks of FGLs      [RFC8383]
464                4     List of FGLs        [RFC8383]
465                5     Bit Map of FGLs     [RFC8383]
466                6     All Data Labels     [RFC8383]
467                7     MAC Address List    [RFC8383]
468                8     MAC Address Blocks  [RFC8383]
469            9-254     Unassigned
470              255     Reserved            [RFC8383]
471]]></artwork>
472 </figure>
473
474 <t><list style="hanging" hangIndent="3"><t hangText="Length:">The 8-bit unsigned integer length in bytes of the
475 remaining information in the TLV after the length byte. The
476         length MUST NOT imply that the value extends beyond the end of the
477         RBridge Channel Protocol Specific Payload area. If it does, the
478         Address Flush message is corrupt and MUST be ignored.
479 </t>
480
481 </list>
482 </t>
483
484
485
486 <t><list hangIndent="3" style="hanging"><t hangText="Value:">Depends on the TLV type.</t>
487
488 </list>
489 </t>
490
491 <t>
492   In an extensible Address Flush message, when the TLVs are parsed,
493   those TLVs having unknown types are ignored by the receiving RBridge.
494   There may be multiple instances of TLVs with the same Type in the
495   same address flush message, and TLVs are not required to be in any
496   particular order.</t>
497
498 <t><list style="symbols"><t>All RBridges implementing the Address Flush RBridge Channel
499      message MUST implement types 1 and 2, the VLAN types, and type 6,
500      which indicates addresses are to be flushed for all Data Labels.</t>
501
502 <t>RBridges that implement the Address Flush message and implement
503      FGL ingress/egress MUST implement types 3, 4, and 5, the FGL
504      types. (An RBridge that is merely FGL safe <xref target="RFC7172"/>, but cannot
505      egress FGL TRILL Data packets, SHOULD ignore the FGL types, as it
506      will not learn any FGL-scoped MAC addresses from the data plane.)</t>
507
508 <t>RBridges that implement the Address Flush message SHOULD implement
509      types 7 and 8 so that specific MAC addresses can be flushed. If
510      they do not, the effect will be to flush all MAC addresses for the
511      indicated Data Labels, which may be inefficient as any MAC
512      addresses not intended to be flushed will have to be relearned.</t>
513
514 </list>
515 </t>
516
517 <t>
518   The parsing of the TLVs by a receiving RBridge results in three pieces
519   of information:</t>
520
521 <t><list style="empty" hangIndent="3">
522 <t><list style="numbers"><t>a flag indicating whether one or more Type 6 TLVs (All Data
523         Labels) were encountered;</t>
524
525 <t>a set of Data Labels accumulated from VLAN and/or FGL
526         specifying TLVs in the message; and,</t>
527<!--[rfced] This sentence does not seem to parse.  Please rephrase.
528
529Original:
530if the MAC address TLV types are implemented, and a set of MAC
531addresses accumulated from MAC address specifying TLVs in the message.
532
533-->
534 <t>if the MAC address TLV types are implemented, and a set of MAC
535         addresses accumulated from MAC address specifying TLVs in the
536         message.</t>
537
538 </list>
539 </t>
540
541 </list>
542 </t>
543
544 <t>
545   VLANs/FGLs might be indicated more than once due to overlapping
546   blocks or the like, and a VLAN/FGL is included in the above set of
547   VLANs/FGLs if it occurs in any TLV in the address flush message. A
548   MAC address might be indicated more than once due to overlapping
549   blocks or the like, and a particular MAC address is included in the above set of
550   MAC addresses if it occurs in any TLV in the address flush message.</t>
551
552 <t>
553   After the above information has been accumulated by parsing the TLVs,
554   three sets are derived as described below: a set of nicknames, a set
555   of Data Labels, and a set of MAC addresses. The address flush
556   operation at the receiver applies to the cross product of these
557   derived sets. That is, a { Data Label, MAC address, nickname } triple
558   is flushed if and only if the Data Label matches an element in the
559   derived set of Data Labels, the MAC address matches an element in the
560   derived set of MAC address, and the nickname matches an element in
561   the derived set of nicknames. In the case of Data Labels and MAC
562   addresses, a special value of the set, {ALL}, is permitted, which
563   matches all values.</t>
564
565   <figure><artwork><![CDATA[
566   The sets are derived as follows:
567   
568      Data Labels set:
569         If the Type 6 TLV has been encountered, the set is {ALL}, else,
570         if any Data Labels have been accumulated by processing Data
571            Label TLVs (Types 1, 2, 3, 4, and 5), the set is those
572            accumulated Data Labels, else,
573         the Data Labels set is null and the address flush message does
574            nothing.
575
576      MAC Addresses set:
577         In the receiver does not implement the MAC address types (Types
578            7 and 8) or it does implement those types but no MAC
579            addresses are accumulated in parsing the TLVs, then the MAC
580            Address set is {ALL},
581         else, the MAC Addresses set is the set of MAC addresses
582            accumulated in processing the TLVs.
583
584      Nicknames set:
585         If the K-nicks field in the Address Flush message was zero,
586            then the ingress nickname in the TRILL Header of the message
587            is the sole nickname set member, else,
588         the nicknames set members are the K-nicks nicknames listed in
589            the Address Flush message.
590]]></artwork>
591 </figure>
592
593 <t>
594   The various formats below are provided for encoding efficiency. A
595   block of values is most efficient when there are a number of
596   consecutive values. A bit map is most efficient if there are
597   scattered values within a limited range. And a list of single values
598   is most efficient if there are widely scattered values.</t>
599
600 <section title="Blocks of VLANs" anchor="section-2.2.1"><t>
601   If the TLV Type is 1, the value is a list of blocks of VLANs as
602   follows:</t>
603
604 <figure><artwork><![CDATA[
605   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
606   | Type = 1      | Length        |
607   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
608   | RESV  | Start.VLAN 1          | RESV  | End.VLAN 1            |
609   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
610   | RESV  | Start.VLAN 2          | RESV  | End.VLAN 2            |
611   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
612   | RESV  | Start.VLAN ...        | RESV  | End.VLAN ...          |
613   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
614]]></artwork>
615 </figure>
616 <t>
617   The meaning of Start.VLAN and End.VLAN is as specified in <xref target="section-2.1"/>. Length MUST be a multiple of 4. If Length is not a multiple of
618   4, the TLV is corrupt and the Address Flush message MUST be
619   discarded.</t>
620
621 </section>
622
623 <section title="Bit Map of VLANs" anchor="section-2.2.2"><t>If the TLV Type is 2, the value is a bit map of VLANs as follows:</t>
624
625 <figure><artwork><![CDATA[
626   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
627   | Type = 2      | Length        |
628   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
629   | RESV  | Start.VLAN            | Bits...
630   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
631]]></artwork>
632 </figure>
633 <t>
634   The value portion of the TLV begins with two bytes having the 12-bit
635   starting VLAN ID right justified (the top 4 bits are as specified in
636   <xref target="section-2.1"/> RESV). This is followed by bytes with one bit per VLAN
637   ID. The high order bit of the first byte is for VLAN N. The next-to-the-highest order bit is for VLAN N+1. The low order bit of the first
638   byte is for VLAN N+7.  The high order bit of the second byte, if there
639   is a second byte, is for VLAN N+8, and so on. If that bit is a one,
640   the Address Flush message applies to that VLAN. If that bit is a
641   zero, then addresses that have been learned in that VLAN are not
642   flushed.  Note that Length MUST be at least 2. If Length is 0 or 1,
643   the TLV is corrupt and the Address Flush message MUST be discarded.
644   VLAN IDs do not wrap around. If there are enough bytes so that some
645   bits correspond to VLAN ID 0xFFF or higher, those bits are ignored,
646   but the message is still processed for bits corresponding to valid
647   VLAN IDs.</t>
648
649 </section>
650
651 <section title="Blocks of FGLs" anchor="section-2.2.3"><t>
652   If the TLV Type is 3, the value is a list of blocks of FGLs as
653   follows:</t>
654
655 <figure><artwork><![CDATA[
656   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
657   | Type = 3      | Length        |
658   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
659   | Start.FGL 1                                   |
660   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
661   | End.FGL 1                                     |
662   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
663   | Start.FGL 2                                   |
664   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
665   | End.FGL 2                                     |
666   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
667   | Start.FGL ...                                 |
668   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
669   | End.FGL ...                                   |
670   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
671]]></artwork>
672 </figure>
673 <t>
674   The TLV value consists of sets of Start.FGL and End.FGL numbers. The
675   Address Flush information applies to the FGLs in that range,
676   inclusive. A single FGL is indicated by setting both Start.FGL and
677   End.FGL to the same value. If End.FGL is less than Start.FGL,
678   considering them as unsigned integers, that block is ignored, but the
679   Address Flush message is still processed for any other blocks
680   present. For this Type, Length MUST be a multiple of 6; if it is not,
681   the TLV is corrupt and the Address Flush message MUST be discarded if
682   the receiving RBridge implements Type 3.</t>
683
684 </section>
685
686 <section title="list of FGLs" anchor="section-2.2.4"><t>If the TLV Type is 4, the value is a list of FGLs as follows:</t>
687
688 <figure><artwork><![CDATA[
689   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
690   | Type = 4      | Length        |
691   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
692   | FGL 1                                         |
693   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
694   | FGL 2                                         |
695   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
696   | FGL ...                                       |
697   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
698]]></artwork>
699 </figure>
700 <t>
701   The TLV value consists of FGL numbers each in 3 bytes. The Address
702   Flush message applies to those FGLs. For this Type, Length MUST be a
703   multiple of 3; if it is not, the TLV is corrupt and the address flush
704   Message MUST be discarded if the receiving RBridge implements Type 4.</t>
705
706 </section>
707
708 <section title="Big Map of FGLs" anchor="section-2.2.5"><t>If the TLV Type is 5, the value is a bit map of FGLs as follows:</t>
709
710
711 <figure><artwork><![CDATA[
712   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
713   | Type = 5      | Length        |
714   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
715   | Start.FGL                                     |
716   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
717   | Bits...
718   +-+-+-+-+-+-+-+-
719]]></artwork>
720 </figure>
721 <t>
722   The TLV value consists of three bytes with the 24-bit starting FGL
723   value N. This is followed by bytes with one bit per FGL. The high
724   order bit of the first byte is for FGL N. The next-to-the-highest
725   order bit is for FGL N+1.  The low order bit of the first byte is for
726   FGL N+7. The high order bit of the second byte, if there is a second
727   byte, is for FGL N+8, and so on. If that bit is a one, the Address
728   Flush message applies to that FGL. If that bit is a zero, then
729   addresses that have been learned in that FGL are not flushed. Note
730   that Length MUST be at least 3. If Length is 0, 1, or 2 for a Type 5
731   TLV, the TLV is corrupt and the Address Flush message MUST be
732   discarded if type 5 is implemented.  FGLs do not wrap around. If
733   there are enough bytes so that some bits correspond to an FGL higher
734   than 0xFFFFFF, those bits are ignored, but the message is still
735   processed for bits corresponding to valid FGLs.</t>
736
737 </section>
738
739 <section title="All Data Labels" anchor="section-2.2.6"><t>If the TLV Type is 6, the value is null as follows:</t>
740
741 <figure><artwork><![CDATA[
742   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
743   | Type = 6      | Length = 0    |
744   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
745]]></artwork>
746 </figure>
747 <t>
748   This type is used when an RBridge wants to withdraw all addresses for
749   all the Data Labels (all VLANs and FGLs). Length MUST be zero. If
750   Length is any other value, the TLV is corrupt and the Address Flush
751   message MUST be discarded.</t>
752
753 </section>
754
755 <section title="MAC Address List" anchor="section-2.2.7"><t>
756   If the TLV Type is 7, the value is a list of MAC addresses as
757   follows:</t>
758
759 <figure><artwork><![CDATA[
760   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
761   | Type = 7      | Length        |
762   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
763   | MAC 1 upper half                              |
764   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
765   | MAC 1 lower half                              |
766   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
767   | MAC 2 upper half                              |
768   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
769   | MAC 2 lower half                              |
770   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
771   | MAC ... upper half                            |
772   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
773   | MAC ... lower half                            |
774   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
775]]></artwork>
776 </figure>
777 <t>
778   The TLV value consists of a list of 48-bit MAC addresses. Length MUST
779   be a multiple of 6. If it is not, the TLV is corrupt, and the Address
780   Flush message MUST be discarded if the receiving RBridge implements
781   Type 7.</t>
782
783 </section>
784
785 <section title="MAC Address Blocks" anchor="section-2.2.8"><t>
786   If the TLV Type is 8, the value is a list of blocks of MAC addresses
787   as follows:</t>
788
789 <figure><artwork><![CDATA[
790   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
791   | Type = 8      | Length        |
792   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
793   | MAC.start 1 upper half                        |
794   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
795   | MAC.start 1 lower half                        |
796   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
797   | MAC.end 1 upper half                          |
798   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
799   | MAC.end 1 lower half                          |
800   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
801   | MAC.start 2 upper half                        |
802   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
803   | MAC.start 2 lower half                        |
804   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
805   | MAC.end 2 upper half                          |
806   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
807   | MAC.end 2 lower half                          |
808   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
809   | MAC.start ... upper half                      |
810   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
811   | MAC.start ... lower half                      |
812   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
813   | MAC.end ... upper half                        |
814   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
815   | MAC.end ... lower half                        |
816   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
817]]></artwork>
818 </figure>
819 <t>
820   The TLV value consists of sets of Start.MAC and End.MAC numbers. The
821   Address Flush information applies to the 48-bit MAC Addresses in that
822   range, inclusive. A single MAC address is indicated by setting both
823   Start.MAC and End.MAC to the same value. If End.MAC is less than
824   Start.MAC, considering them as unsigned integers, that block is
825   ignored but the Address Flush message is still processed for any
826   other blocks present. For this Type, Length MUST be a multiple of 12;
827   if it is not, the TLV is corrupt and the Address Flush message MUST
828   be discarded if the receiving RBridge implements Type 7.</t>
829
830 </section>
831
832 </section>
833
834 </section>
835
836 <section title="IANA Considerations" anchor="section-3">
837
838 <section title="Address Flush RBridge Channel Protocol Number" anchor="section-3.1"><t>
839   IANA has assigned 0x009 as the Address Flush RBridge Channel
840   Protocol number from the range of RBridge Channel protocols allocated
841   by Standards Action <xref target="RFC7178"/> <xref target="RFC8126"/>.</t>
842
843 <t>
844   The added entry to the "RBridge Channel Protocols" registry at &lt;https://www.iana.org/assignments/trill-parameters/&gt; is as follows:</t>
845
846 <figure><artwork><![CDATA[
847      Protocol  Description       Reference
848      --------  --------------    ------------------
849        0x009    Address Flush     [RFC8383]
850]]></artwork>
851 </figure>
852 </section>
853
854 <section title="TRILL Address Flush TLV Types" anchor="section-3.2"><t>
855   IANA has created the "TRILL Address Flush TLV Types" registry
856   at  &lt;https://www.iana.org/assignments/trill-parameters/&gt; as a subregistry of the "RBridge Channel
857   Protocols" registry.
858
859   <!--[rfced] Please review our update to the description of the relationship between the "RBridge Channel Protocols" registry and the "TRILL Address Flush TLV Types" registry (i.e., please confirm that the latter is a subregistry).
860
861-->
862   Registry headers are as below. The initial
863   entries are as in the table in <xref target="section-2.2"/>.</t>
864
865<figure><artwork><![CDATA[
866      Registry:  TRILL Address Flush TLV Types
867      Registration Procedures: IETF Review
868      Reference:  [RFC8383]
869]]></artwork>
870 </figure>   
871      
872 
873
874 </section>
875
876 </section>
877
878 <section title="Security Considerations" anchor="section-4"><t>
879   The Address Flush RBridge Channel Protocol itself provides no
880   security assurances or features. However, Address Flush protocol
881   messages can be secured by use of the RBridge Channel Header
882   Extension <xref target="RFC7978"/>. It is RECOMMENDED that all RBridges that
883   implement the address flush message be configured to ignore such
884   messages unless they have been secured with an RBridge Channel Header
885   Extension that meets local security policy.</t>
886
887 <t>
888   If RBridges receiving Address Flush messages do not require them to
889   be at least authenticated, they are relatively easy to forge. In that
890   case, such forged Address Flush messages can reduce network
891   efficiency, by purging useful learned information that will have to
892   be relearned. This provides a denial-of-service attack, but cannot
893   cause incorrect operation in the sense that it cannot cause a frame
894   to be improperly delivered.</t>
895
896 <t>
897   See <xref target="RFC7178"/> for general RBridge Channel Security Considerations.</t>
898
899 <t>
900   See <xref target="RFC6325"/> for general TRILL Security Considerations.</t>
901
902 </section>
903      </middle>
904      <back>
905
906
907
908   <references title="Normative References">
909
910   <?rfc include="reference.RFC.2119"?>
911   <?rfc include="reference.RFC.6325"?>
912   <?rfc include="reference.RFC.7172"?>
913   <?rfc include="reference.RFC.7178"?>
914   <?rfc include="reference.RFC.7780"?>
915   <?rfc include="reference.RFC.7978"?>
916   <?rfc include="reference.RFC.8174"?>
917
918
919 </references>
920
921 <references title="Informative References">
922
923   <?rfc include="reference.RFC.4762"?>
924    <?rfc include="reference.RFC.8126"?>
925   
926 </references>
927
928
929 <section title="Acknowledgements" numbered="no" anchor="acknowledgements"><t><list style="hanging" hangIndent="3"><t hangText="The following are thanked for their contributions:">
930 <vspace blankLines="1"/>
931 Ramkumar Parameswaran, Henning Rogge
932 </t>
933
934 </list>
935      </t>
936
937<!--[rfced] Throughout the text, the following terminology appears to be used inconsistently.  
938
939Please review these occurrences and let us know if/how they may be made 
940consistent.
941
942RBridge Channel messages vs. RBridge Channel protocol message
943
944Address Flush message vs. address flush messages vs. address flush Message
945
946type # vs. Type # (e.g., type 6 vs. Type 6)
947
948length bypte vs. Length byte
949
950-->
951
952
953 </section>
954
955 </back>
956
957 </rfc>
958
  • <?xml version="1.0" encoding="us-ascii"?>
  • <!DOCTYPE rfc SYSTEM "rfc2629.dtd">
  • <rfc submissionType="IETF" category="std" consensus="yes" number="8383" obsoletes="" updates="" {http://www.w3.org/XML/1998/namespace}lang="en">
    • <?rfc compact="yes"?>
    • <?rfc text-list-symbols="-o*+"?>
    • <?rfc subcompact="no"?>
    • <?rfc sortrefs="yes"?>
    • <?rfc symrefs="yes"?>
    • <?rfc strict="yes"?>
    • <?rfc toc="yes"?>
    • <front>
      • <title abbrev="TRILL Address Flush Message">
        • Transparent Interconnection of Lots of Links (TRILL): Address Flush Message
        • </title>
      • <author fullname="Weiguo Hao" initials="W." surname="Hao">
        • <organization abbrev="Huawei">
          • Huawei Technologies
          • </organization>
        • <address>
          • <postal>
            • <street>
              • 101 Software Avenue,
              • </street>
            • <street>
              • Nanjing 210012
              • </street>
            • <street>
              • China
              • </street>
            • </postal>
          • <phone>
            • +86-25-56623144
            • </phone>
          • <email>
            • haoweiguo@huawei.com
            • </email>
          • </address>
        • </author>
      • <author fullname="Donald Easlake 3rd" initials="D." surname="Eastlake, 3rd">
        • <organization abbrev="Huawei">
          • Huawei Technologies
          • </organization>
        • <address>
          • <postal>
            • <street>
              • 155 Beaver Street
              • </street>
            • <street>
              • Milford, MA 01757
              • </street>
            • <street>
              • United States of America
              • </street>
            • </postal>
          • <phone>
            • +1-508-333-2270
            • </phone>
          • <email>
            • d3e3e3@gmail.com
            • </email>
          • </address>
        • </author>
      • <author fullname="Yizhou Li" initials="Y." surname="Li">
        • <organization abbrev="Huawei">
          • Huawei Technologies
          • </organization>
        • <address>
          • <postal>
            • <street>
              • 101 Software Avenue,
              • </street>
            • <street>
              • Nanjing 210012
              • </street>
            • <street>
              • China
              • </street>
            • </postal>
          • <phone>
            • +86-25-56624629
            • </phone>
          • <email>
            • liyizhou@huawei.com
            • </email>
          • </address>
        • </author>
      • <author fullname="Mohammed Umair" initials="M." surname="Umair">
        • <organization>
          • Cisco
          • </organization>
        • <address>
          • <postal>
            • <street>
              • Cessna Business Park, Kadubeesanahalli Village, Hobli,
              • </street>
            • <street>
              • Sarjapur, Varthur Main Road, Marathahalli,
              • </street>
            • <street>
              • Bengaluru, Karnataka 560087
              • </street>
            • <street>
              • India
              • </street>
            • </postal>
          • <email>
            • mohammed.umair2@gmail.com
            • </email>
          • </address>
        • </author>
      • <date month="May" year="2018"/>
      • <workgroup>
        • TRILL Working Group
        • </workgroup>
      • <-- [rfced] Please insert any keywords (beyond those that appear in the title) for use on https://www.rfc-editor.org/search.   -->
      • <keyword>
        • example
        • </keyword>
      • <abstract>
        • <t>
          • The TRILL (Transparent Interconnection of Lots of Links) protocol, by default, learns end station addresses from observing the data plane. In particular, it learns local Media Access Control (MAC) addresses and the edge switch port of attachment from the receipt of local data frames and learns remote MAC addresses and the edge switch port of attachment from the decapsulation of remotely sourced TRILL Data packets.
          • </t>
        • <t>
          • This document specifies a message by which a TRILL switch can explicitly request other TRILL switches to flush certain MAC reachability learned through the decapsulation of TRILL Data packets.
          • <-- [rfced] To what does "the TRILL automatic address forgetting" refer?  Will the reader understand this phrase? Original: This is a supplement to the TRILL automatic address forgetting and can assist in achieving more rapid convergence in case of topology or configuration change.   -->
          • This is a supplement to the TRILL automatic address forgetting and can assist in achieving more rapid convergence in case of topology or configuration change.
          • This document specifies a message by which a TRILL switch can explicitly request other TRILL switches to flush certain MAC reachability learned through the decapsulation of TRILL Data packets. This is a supplement to the TRILL automatic address forgetting (see Section 4.8.3 of <xref target="RFC6325" format="default" pageno="false"/>) and can assist in achieving more rapid convergence in case of topology or configuration change.) and can assist in achieving more rapid convergence in case of topology or configuration change.
          • </t>
        • </abstract>
      • </front>
    • <middle>
      • <section title="Introduction" anchor="section-1" numbered="true" toc="default">
        • <t>
          • By default, edge TRILL (Transparent Interconnection of Lots of Links) switches <xref target="RFC6325" format="default" pageno="false"/> <xref target="RFC7780" format="default" pageno="false"/>, also called edge Routing Bridges (RBridges), learn end station MAC address reachability from observing the data plane. On receipt of a native frame from an end station, they would learn the local MAC address attachment of the source end station. And on egressing (decapsulating) a remotely originated TRILL Data packet, they learn the remote MAC address and remote attachment TRILL switch. Such learning is all scoped by data label (VLAN or Fine-Grained Label (FGL) , also called edge Routing Bridges (RBridges), learn end station MAC address reachability from observing the data plane. On receipt of a native frame from an end station, they would learn the local MAC address attachment of the source end station. And on egressing (decapsulating) a remotely originated TRILL Data packet, they learn the remote MAC address and remote attachment TRILL switch. Such learning is all scoped by data label (VLAN or Fine-Grained Label (FGL) <xref target="RFC7172" format="default" pageno="false"/>).).
          • </t>
        • <t>
          • TRILL has mechanisms for timing out such learning and appropriately clearing it based on some network connectivity and configuration changes; however, there are circumstances under which it would be helpful for a TRILL switch to be able to explicitly flush (purge) certain learned end station reachability information in remote RBridges to achieve more-rapid convergence. Section 6.2 of <xref target="RFC4762" format="default" pageno="false"/> is an example of the use of such a mechanism. is an example of the use of such a mechanism.
          • </t>
        • <t>
          • Another example, based on Appendix A.3 of <xref target="RFC6325" format="default" pageno="false"/> ("Wiring Closet Topology"), presents a bridged LAN connected to a TRILL network via multiple RBridge ports. For optimum paths, Appendix A.3.3 suggests configuring the RBridge ports to be like one Spanning Tree Protocol (STP) tree root in the bridged LAN. The address fAddress Flush message in this document could also be triggered in this case when one of the edge RBridges receives Topology Change (TC) information (e.g., TC in STP, Topology Change Notification (TCN) in Multiple Spanning Tree Protocol (MSTP) in order to rapidly flush the MAC addresses for specific VLANs learned at the other edge RBridge ports. ("Wiring Closet Topology"), presents a bridged LAN connected to a TRILL network via multiple RBridge ports. For optimum paths, Appendix A.3.3 suggests configuring the RBridge ports to be like one Spanning Tree Protocol (STP) tree root in the bridged LAN. The address fAddress Flush message in this document could also be triggered in this case when one of the edge RBridges receives Topology Change (TC) information (e.g., TC in STP, Topology Change Notification (TCN) in Multiple Spanning Tree Protocol (MSTP) in order to rapidly flush the MAC addresses for specific VLANs learned at the other edge RBridge ports.
          • </t>
        • <t>
          • A TRILL switch can easily flush any locally learned addresses it wants. This document specifies an RBridge Channel Support protocol <xref target="RFC7178" format="default" pageno="false"/> message to request flushing address information for specific VLANs or FGLs ( message to request flushing address information for specific VLANs or FGLs (<xref target="RFC7172" format="default" pageno="false"/>) learned from decapsulating TRILL Data packets.) learned from decapsulating TRILL Data packets.
          • </t>
        • <section title="Terminology and Abbreviations" anchor="section-1.1" numbered="true" toc="default">
          • <t>
            • The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in <xref target="RFC2119" format="default" pageno="false"/> <xref target="RFC8174" format="default" pageno="false"/> when, and only when, they appear in all capitals, as shown here. when, and only when, they appear in all capitals, as shown here.
            • </t>
          • <t>
            • This document uses the terms and abbreviations defined in <xref target="RFC6325" format="default" pageno="false"/> and and <xref target="RFC7978" format="default" pageno="false"/> as well as the following: as well as the following:
            • </t>
          • <t>
            • <list hangIndent="3" style="hanging">
              • <t hangText="Data Label:">
                • A VLAN or FGL
                • </t>
              • <t hangText="Edge TRILL Switch:">
                • A TRILL switch attached to one or more links that provide end station service
                • </t>
              • <t hangText="FCS:">
                • Frame Check Sequence
                • </t>
              • <t hangText="FGL:">
                • Fine-Grained Label <xref target="RFC7172" format="default" pageno="false"/>
                • </t>
              • <t hangText="Management VLAN:">
                • A VLAN in which all TRILL switches in a campus indicate interest so that multi-destination TRILL Data packets, including RBridge Channel protocol messages <xref target="RFC7978" format="default" pageno="false"/>, sent with that VLAN as the Inner.VLAN will be delivered to all TRILL switches in the campus. Usually, no end station service is offered in the Management VLAN. , sent with that VLAN as the Inner.VLAN will be delivered to all TRILL switches in the campus. Usually, no end station service is offered in the Management VLAN.
                • </t>
              • <t hangText="MAC:">
                • Media Access Control
                • </t>
              • <t hangText="RBridge:">
                • An alternative name for a TRILL switch
                • </t>
              • <t hangText="STP:">
                • Spanning Tree Protocol
                • </t>
              • <t hangText="TC:">
                • Topology Change message
                • </t>
              • <t hangText="TCN:">
                • Topology Change Notification message
                • </t>
              • <t hangText="TRILL switch:">
                • A device implementing the TRILL protocol RFC 6235 <xref target="RFC7780" format="default" pageno="false"/>
                • </t>
              • </list>
            • </t>
          • </section>
        • </section>
      • <section title="Address Flush Message Details" anchor="section-2" numbered="true" toc="default">
        • <t>
          • The Address Flush message is an RBridge Channel protocol message <xref target="RFC7178" format="default" pageno="false"/>..
          • </t>
        • <t>
          • The general structure of an RBridge Channel packet on a link between TRILL switches is shown in <xref target="ref-rbridge-channel-protocol-message-structure" format="default" pageno="false"/>. The Protocol field in the RBridge Channel Header gives the type of RBridge Channel packet and indicates how to interpret the Channel -Protocol -Specific Payload . The Protocol field in the RBridge Channel Header gives the type of RBridge Channel packet and indicates how to interpret the Channel -Protocol -Specific Payload <xref target="RFC7178" format="default" pageno="false"/>. .
          • <-- [rfced] RFC 7178 does not use the specific term "Channel Protocol Specific Payload".  We note that RFC-to-be 8381 updated to use "Channel-Protocol-Specific Payload".  Please review the use of this term in this document and the other two and let us know if updates should be made.   -->
          • <xref target="RFC7178" format="default" pageno="false"/>. .
          • </t>
        • <-- [rfced] We note that the content of Figure 1 is an exact replica of Figure 1 in RFC-to-be 8381.  Only the titles are different.  Please confirm that this is intentional and no updates should be made.  RFC 8381: RBridge Channel Packet Structure This document: RBridge Channel Protocol Message Structure  -->
        • <figure title="RBridge Channel Protocol Message Structure" anchor="ref-rbridge-channel-protocol-message-structure" suppress-title="false" align="left" alt="" width="" height="">
          • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">


            •                    +-----------------------------------+
                                 |            Link Header            |
                                 +-----------------------------------+
                                 |            TRILL Header           |
                                 +-----------------------------------+
                                 |      Inner Ethernet Addresses     |
                                 +-----------------------------------+
                                 |      Data Label (VLAN or FGL)     |
                                 +-----------------------------------+
                                 |       RBridge Channel Header      |
                                 +-----------------------------------+
                                 | Channel
               -Protocol -Specific Payload |
                                 +-----------------------------------+
                                 |   Link Trailer (FCS if Ethernet)  |
                                 +-----------------------------------+
            • </artwork>
          • </figure>
        • <t>
          • By default, an Address Flush RBridge Channel protocol message applies to addresses within the Data Label that appear right after the Inner Ethernet Addresses. Address Flush protocol messages are usually sent as multi-destination packets (TRILL Header M bit equal to one) so as to reach all TRILL switches offering end station service in the VLAN or FGL specified by that Data Label. Both multi-destination and unicast Address Flush messages SHOULD be sent at priority 6 since they are important control messages but are lower priority than control messages that establish or maintain adjacency.
          • </t>
        • <t>
          • Nevertheless:
          • </t>
        • <t>
          • <list style="symbols">
            • <t>
              • There are provisions for optionally indicating the Data Label(s) to be flushed for cases where the Address Flush message is sent over a Management VLAN or the like.
              • </t>
            • <t>
              • An Address Flush message can be sent unicast, if it is desired to clear addresses at one TRILL switch only.
              • </t>
            • <t>
              • An Address Flush message can be sent selectively to the RBridges that have at least one access port configured as one of the VLANs or FGLs specified in the Address Flush message payload.
              • </t>
            • </list>
          • </t>
        • <t>
          • Implementations should consider logging aAddress fFlush messages received with appropriate protections against packet storms.
          • </t>
        • <section title="VLAN Block Only Case" anchor="section-2.1" numbered="true" toc="default">
          • <t>
            • <xref target="ref-address-flush-message-vlan-block-case" format="default" pageno="false"/> expands the RBridge Channel Header and Channel -Protocol -Specific Payload from expands the RBridge Channel Header and Channel -Protocol -Specific Payload from <xref target="ref-rbridge-channel-protocol-message-structure" format="default" pageno="false"/> for the case of the VLAN-only-based Address Flush message. This form of the Address Flush message is optimized for flushing MAC addresses based on nickname and blocks of VLANs. 0x8946 is the Ethertype assigned by IEEE for the RBridge Channel protocol. for the case of the VLAN-only-based Address Flush message. This form of the Address Flush message is optimized for flushing MAC addresses based on nickname and blocks of VLANs. 0x8946 is the Ethertype assigned by IEEE for the RBridge Channel protocol.
            • </t>
          • <-- [rfced] Would a pointer to an IEEE registry be needed/wanted by the reader or others?  If so, please let us know how to update.  Original: 0x8946 is the Ethertype assigned by IEEE for the RBridge Channel protocol  -->
          • <figure title="Address Flush Message - VLAN Block Case" anchor="ref-address-flush-message-vlan-block-case" suppress-title="false" align="left" alt="" width="" height="">
            • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">

              •     0                   1                   2                   3
                    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
                RBridge Channel Header:
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   |    RBridge-Channel (0x8946)   |  0x0  |Channel Protocol= 0x009|
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   |          Flags        |  ERR  |
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                Address Flush Protocol Specific:
                   +-+-+-+-+-+-+-+-+
                   | K-nicks       |
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   | Nickname 1                    | Nickname 2                    |
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   | Nickname ...                  | Nickname K-nicks              |
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   | K-VLBs        |
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   | RESV  | Start.VLAN 1          | RESV  | End.VLAN 1            |
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   | RESV  | Start.VLAN 2          | RESV  | End.VLAN 2            |
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   | RESV  | Start.VLAN ...        | RESV  | End.VLAN ...          |
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   | RESV  | Start.VLAN K-VLBs     | RESV  | End.VLAN K-VLBs       |
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              • </artwork>
            • </figure>
          • <t>
            • The fields in <xref target="ref-address-flush-message-vlan-block-case" format="default" pageno="false"/> related to the Address Flush message are as follows: related to the Address Flush message are as follows:
            • </t>
          • <t>
            • <list style="hanging" hangIndent="3">
              • <t hangText="Channel Protocol:">
                • The RBridge Channel Protocol value allocated for Address Flush (see <xref target="section-3" format="default" pageno="false"/>). ).
                • </t>
              • <t hangText="K-nicks:">
                • The number of nicknames listed as an unsigned integer. If this is zero, the ingress nickname in the TRILL Header <xref target="RFC6325" format="default" pageno="false"/> is considered to be the only nickname to which the message applies. If non-zero, it gives the number of nicknames listed right after K-nicks to which the message applies, and, in this non-zero case, the flush does not apply to the ingress nickname in the TRILL Header unless it is also listed. The message flushes address learning due to egressing TRILL Data packets that had an ingress nickname to which the message applies. is considered to be the only nickname to which the message applies. If non-zero, it gives the number of nicknames listed right after K-nicks to which the message applies, and, in this non-zero case, the flush does not apply to the ingress nickname in the TRILL Header unless it is also listed. The message flushes address learning due to egressing TRILL Data packets that had an ingress nickname to which the message applies.
                • </t>
              • <t hangText="Nickname:">
                • A listed nickname to which it is intended that the Address Flush message apply. If an unknown or reserved nickname occurs in the list, it is ignored, but the address flush operation is still executed with the other nicknames. If an incorrect nickname occurs in the list, so that some address learning is flushed that should not have been flushed, the network will still operate correctly; however, it will be less efficient as the incorrectly flushed learning is relearned.
                • </t>
              • <t hangText="K-VLBs:">
                • The number of VLAN blocks present as an unsigned integer. If this byte is zero, the message is the more general format specified in <xref target="section-2.2" format="default" pageno="false"/>. If it is non-zero, it gives the number of blocks of VLANs present. Thus, in the VLAN Block address flush case, K-VLBs will be at least one. . If it is non-zero, it gives the number of blocks of VLANs present. Thus, in the VLAN Block address flush case, K-VLBs will be at least one.
                • </t>
              • <t hangText="RESV:">
                • 4 reserved bits. MUST be sent as zero and ignored on receipt.
                • </t>
              • <t hangText="Start.VLAN, End.VLAN:">
                • These 12-bit fields give the beginning and ending VLAN IDs of a block of VLANs. The block includes both the starting and ending values; so, a block of size one is indicated by setting End.VLAN equal to Start.VLAN. If Start.VLAN is 0x000, it is treated as if it was 0x001. If End.VLAN is 0xFFF, it is treated as if it was 0xFFE. If End.VLAN is smaller than Start.VLAN, considering both as unsigned integers, that VLAN block is ignored, but the address flush operation is still executed with other VLAN blocks in the message. VLAN blocks may overlap, in which case, the address flush operation is applicable to a VLAN covered by any one or more of the blocks in the message.
                • </t>
              • </list>
            • </t>
          • <t>
            • This message flushes all addresses in an applicable VLAN learned from egressing TRILL Data packets with an applicable nickname as ingress. To flush addresses for all VLANs, it is easy to specify a block covering all valid VLAN IDs (i.e., from 0x001 to 0xFFE).
            • </t>
          • </section>
        • <section title="Extensible Case" anchor="section-2.2" numbered="true" toc="default">
          • <t>
            • A more general form of the Address Flush message is provided to support flushing by FGL and more efficient encodings of VLANs and FGLs where using a set of contiguous blocks is cumbersome. It also supports optionally specifying the MAC addresses to clear. This form is extensible.
            • </t>
          • <t>
            • The extensible case is indicated by a zero in the byte shown in <xref target="ref-address-flush-message-vlan-block-case" format="default" pageno="false"/> as "K-VLBs" followed by other information encoded as TLVs. as "K-VLBs" followed by other information encoded as TLVs.
            • </t>
          • <figure title="Address Flush Message - Extensible Case" anchor="ref-address-flush-message-extensible-case" suppress-title="false" align="left" alt="" width="" height="">
            • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">

              •     0                   1                   2                   3
                    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
                RBridge Channel Header:
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   |    RBridge-Channel (0x8946)   |  0x0  |Channel Protocol=0x009 |
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   |          Flags        |  ERR  |
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                Address Flush Protocol Specific:
                   +-+-+-+-+-+-+-+-+
                   | K-nicks       |
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   | Nickname 1                    | Nickname 2                    |
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   | Nickname ...                  | Nickname K-nicks              |
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   | 0             |  TLVs ...
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...
              • </artwork>
            • </figure>
          • <t>
            • <list style="hanging" hangIndent="3">
              • <t hangText="Channel Protocol, K-nicks, Nickname:">
                • These fields are as specified in <xref target="section-2.1" format="default" pageno="false"/>. .
                • </t>
              • <t hangText="TLVs:">
                • If the byte immediately before the TLVs field, which is the byte labeled "K-VLBs" in <xref target="ref-address-flush-message-vlan-block-case" format="default" pageno="false"/>, is zero, as shown in , is zero, as shown in <xref target="ref-address-flush-message-extensible-case" format="default" pageno="false"/>, the remainder of the message consists of TLVs encoded as shown in , the remainder of the message consists of TLVs encoded as shown in <xref target="ref-type-length-value" format="default" pageno="false"/>. .
                • </t>
              • </list>
            • </t>
          • <figure title="Type, Length, Value" anchor="ref-type-length-value" suppress-title="false" align="left" alt="" width="" height="">
            • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">

              •           0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
                         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
                         |  Type         |  Length       |  Value
                         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
              • </artwork>
            • </figure>
          • <t>
            • <list style="hanging" hangIndent="3">
              • <t hangText="Type:">
                • The 8-bit TLV type as shown in the table below. See subsections of <xref target="section-2.2" format="default" pageno="false"/> for details on each type assigned below. If the type is reserved or not known by a receiving RBridge, that receiving RBridge ignores the value and skips to the next TLV by use of the Length byte. There is no provision for a list of VLAN ID TLVs as there are few enough of them that an arbitrary subset of VLAN IDs can be represented as a bit map. for details on each type assigned below. If the type is reserved or not known by a receiving RBridge, that receiving RBridge ignores the value and skips to the next TLV by use of the Length byte. There is no provision for a list of VLAN ID TLVs as there are few enough of them that an arbitrary subset of VLAN IDs can be represented as a bit map.
                • </t>
              • </list>
            • </t>
          • <figure title="" suppress-title="false" align="left" alt="" width="" height="">
            • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">

              •              Type       Description       Reference
                            ------   ------------------  -----------------
                                0     Reserved            [RFC8383]
                                1     Blocks of VLANs     [RFC8383]
                                2     Bit Map of VLANs    [RFC8383]
                                3     Blocks of FGLs      [RFC8383]
                                4     List of FGLs        [RFC8383]
                                5     Bit Map of FGLs     [RFC8383]
                                6     All Data Labels     [RFC8383]
                                7     MAC Address List    [RFC8383]
                                8     MAC Address Blocks  [RFC8383]
                            9-254     Unassigned
                              255     Reserved            [RFC8383]
              • </artwork>
            • </figure>
          • <t>
            • <list style="hanging" hangIndent="3">
              • <t hangText="Length:">
                • The 8-bit unsigned integer length in bytes of the remaining information in the TLV after the lLength byte. The lLength MUST NOT imply that the value extends beyond the end of the RBridge Channel -Protocol -Specific Payload area. If it does, the Address Flush message is corrupt and MUST be ignored.
                • </t>
              • </list>
            • </t>
          • <t>
            • <list hangIndent="3" style="hanging">
              • <t hangText="Value:">
                • Depends on the TLV type.
                • </t>
              • </list>
            • </t>
          • <t>
            • In an extensible Address Flush message, when the TLVs are parsed, those TLVs having unknown types are ignored by the receiving RBridge. There may be multiple instances of TLVs with the same Type in the same address fAddress Flush message, and TLVs are not required to be in any particular order.
            • </t>
          • <t>
            • <list style="symbols">
              • <t>
                • All RBridges implementing the Address Flush RBridge Channel protocol message MUST implement types 1 and 2, the VLAN types, and tType 6, which indicates addresses are to be flushed for all Data Labels.
                • </t>
              • <t>
                • RBridges that implement the Address Flush message and implement FGL ingress/egress MUST implement types 3, 4, and 5, the FGL types. (An RBridge that is merely FGL safe <xref target="RFC7172" format="default" pageno="false"/>, but cannot egress FGL TRILL Data packets, SHOULD ignore the FGL types, as it will not learn any FGL-scoped MAC addresses from the data plane.), but cannot egress FGL TRILL Data packets, SHOULD ignore the FGL types, as it will not learn any FGL-scoped MAC addresses from the data plane.)
                • </t>
              • <t>
                • RBridges that implement the Address Flush message SHOULD implement types 7 and 8 so that specific MAC addresses can be flushed. If they do not, the effect will be to flush all MAC addresses for the indicated Data Labels, which may be inefficient as any MAC addresses not intended to be flushed will have to be relearned.
                • </t>
              • </list>
            • </t>
          • <t>
            • The parsing of the TLVs by a receiving RBridge results in three pieces of information:
            • </t>
          • <t>
            • <list style="empty" hangIndent="3">
              • <t>
                • <list style="numbers">
                  • <t>
                    • a flag indicating whether one or more Type 6 TLVs (All Data Labels) were encountered;
                    • </t>
                  • <t>
                    • a set of Data Labels accumulated from VLAN and/or FGL specifying TLVs in the message; and,
                    • </t>
                  • <-- [rfced] This sentence does not seem to parse.  Please rephrase.  Original: if the MAC address TLV types are implemented, and a set of MAC addresses accumulated from MAC address specifying TLVs in the message.   -->
                  • <t>
                    • if the MAC address TLV types are implemented, and a set of MAC addresses accumulated from MAC -address -specifying TLVs in the message.
                    • </t>
                  • </list>
                • </t>
              • </list>
            • </t>
          • <t>
            • VLANs/FGLs might be indicated more than once due to overlapping blocks or the like, and a VLAN/FGL is included in the above set of VLANs/FGLs if it occurs in any TLV in the address fAddress Flush message. A MAC address might be indicated more than once due to overlapping blocks or the like, and a particular MAC address is included in the above set of MAC addresses if it occurs in any TLV in the address fAddress Flush message.
            • </t>
          • <t>
            • After the above information has been accumulated by parsing the TLVs, three sets are derived as described below: a set of nicknames, a set of Data Labels, and a set of MAC addresses. The address flush operation at the receiver applies to the cross product of these derived sets. That is, a { Data Label, MAC address, nickname } triple is flushed if and only if the Data Label matches an element in the derived set of Data Labels, the MAC address matches an element in the derived set of MAC address, and the nickname matches an element in the derived set of nicknames. In the case of Data Labels and MAC addresses, a special value of the set, {ALL}, is permitted, which matches all values.
            • </t>
          • <figure title="" suppress-title="false" align="left" alt="" width="" height="">
            • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">

              •    The sets are derived as follows:
                   
                      Data Labels set:
                         If the Type 6 TLV has been encountered, the set is {ALL}, else,
                         if any Data Labels have been accumulated by processing Data
                            Label TLVs (Types 1, 2, 3, 4, and 5), the set is those
                            accumulated Data Labels, else,
                         the Data Labels set is null and the 
                address fAddress Flush message does
                            nothing.

                      MAC Addresses set:
                         In the receiver does not implement the MAC address types (Types
                            7 and 8) or it does implement those types but no MAC
                            addresses are accumulated in parsing the TLVs, then the MAC
                            Address set is {ALL},
                         else, the MAC Addresses set is the set of MAC addresses
                            accumulated in processing the TLVs.

                      Nicknames set:
                         If the K-nicks field in the Address Flush message was zero,
                            then the ingress nickname in the TRILL Header of the message
                            is the sole nickname set member, else,
                         the nicknames set members are the K-nicks nicknames listed in
                            the Address Flush message.
              • </artwork>
            • </figure>
          • <t>
            • The various formats below are provided for encoding efficiency. A block of values is most efficient when there are a number of consecutive values. A bit map is most efficient if there are scattered values within a limited range. And a list of single values is most efficient if there are widely scattered values.
            • </t>
          • <section title="Blocks of VLANs" anchor="section-2.2.1" numbered="true" toc="default">
            • <t>
              • If the TLV Type is 1, the value is a list of blocks of VLANs as follows:
              • </t>
            • <figure title="" suppress-title="false" align="left" alt="" width="" height="">
              • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">

                •    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | Type = 1      | Length        |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | RESV  | Start.VLAN 1          | RESV  | End.VLAN 1            |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | RESV  | Start.VLAN 2          | RESV  | End.VLAN 2            |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | RESV  | Start.VLAN ...        | RESV  | End.VLAN ...          |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                • </artwork>
              • </figure>
            • <t>
              • The meaning of Start.VLAN and End.VLAN is as specified in <xref target="section-2.1" format="default" pageno="false"/>. Length MUST be a multiple of 4. If Length is not a multiple of 4, the TLV is corrupt and the Address Flush message MUST be discarded.. Length MUST be a multiple of 4. If Length is not a multiple of 4, the TLV is corrupt and the Address Flush message MUST be discarded.
              • </t>
            • </section>
          • <section title="Bit Map of VLANs" anchor="section-2.2.2" numbered="true" toc="default">
            • <t>
              • If the TLV Type is 2, the value is a bit map of VLANs as follows:
              • </t>
            • <figure title="" suppress-title="false" align="left" alt="" width="" height="">
              • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">

                •    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | Type = 2      | Length        |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
                     | RESV  | Start.VLAN            | Bits...
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
                • </artwork>
              • </figure>
            • <t>
              • The value portion of the TLV begins with two bytes having the 12-bit starting VLAN ID right justified (the top 4 bits are as specified in <xref target="section-2.1" format="default" pageno="false"/> RESV). This is followed by bytes with one bit per VLAN ID. The high order bit of the first byte is for VLAN N. The next-to-the-highest order bit is for VLAN N+1. The low order bit of the first byte is for VLAN N+7. The high order bit of the second byte, if there is a second byte, is for VLAN N+8, and so on. If that bit is a one, the Address Flush message applies to that VLAN. If that bit is a zero, then addresses that have been learned in that VLAN are not flushed. Note that Length MUST be at least 2. If Length is 0 or 1, the TLV is corrupt and the Address Flush message MUST be discarded. VLAN IDs do not wrap around. If there are enough bytes so that some bits correspond to VLAN ID 0xFFF or higher, those bits are ignored, but the message is still processed for bits corresponding to valid VLAN IDs. RESV). This is followed by bytes with one bit per VLAN ID. The high order bit of the first byte is for VLAN N. The next-to-the-highest order bit is for VLAN N+1. The low order bit of the first byte is for VLAN N+7. The high order bit of the second byte, if there is a second byte, is for VLAN N+8, and so on. If that bit is a one, the Address Flush message applies to that VLAN. If that bit is a zero, then addresses that have been learned in that VLAN are not flushed. Note that Length MUST be at least 2. If Length is 0 or 1, the TLV is corrupt and the Address Flush message MUST be discarded. VLAN IDs do not wrap around. If there are enough bytes so that some bits correspond to VLAN ID 0xFFF or higher, those bits are ignored, but the message is still processed for bits corresponding to valid VLAN IDs.
              • </t>
            • </section>
          • <section title="Blocks of FGLs" anchor="section-2.2.3" numbered="true" toc="default">
            • <t>
              • If the TLV Type is 3, the value is a list of blocks of FGLs as follows:
              • </t>
            • <figure title="" suppress-title="false" align="left" alt="" width="" height="">
              • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">

                •    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | Type = 3      | Length        |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | Start.FGL 1                                   |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | End.FGL 1                                     |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | Start.FGL 2                                   |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | End.FGL 2                                     |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | Start.FGL ...                                 |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | End.FGL ...                                   |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                • </artwork>
              • </figure>
            • <t>
              • The TLV value consists of sets of Start.FGL and End.FGL numbers. The Address Flush information applies to the FGLs in that range, inclusive. A single FGL is indicated by setting both Start.FGL and End.FGL to the same value. If End.FGL is less than Start.FGL, considering them as unsigned integers, that block is ignored, but the Address Flush message is still processed for any other blocks present. For this Type, Length MUST be a multiple of 6; if it is not, the TLV is corrupt and the Address Flush message MUST be discarded if the receiving RBridge implements Type 3.
              • </t>
            • </section>
          • <section title="list of FGLs" anchor="section-2.2.4" numbered="true" toc="default">
            • <t>
              • If the TLV Type is 4, the value is a list of FGLs as follows:
              • </t>
            • <figure title="" suppress-title="false" align="left" alt="" width="" height="">
              • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">

                •    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | Type = 4      | Length        |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | FGL 1                                         |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | FGL 2                                         |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | FGL ...                                       |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                • </artwork>
              • </figure>
            • <t>
              • The TLV value consists of FGL numbers each in 3 bytes. The Address Flush message applies to those FGLs. For this Type, Length MUST be a multiple of 3; if it is not, the TLV is corrupt and the address flush MAddress Flush message MUST be discarded if the receiving RBridge implements Type 4.
              • </t>
            • </section>
          • <section title="Big Map of FGLs" anchor="section-2.2.5" numbered="true" toc="default">
            • <t>
              • If the TLV Type is 5, the value is a bit map of FGLs as follows:
              • </t>
            • <figure title="" suppress-title="false" align="left" alt="" width="" height="">
              • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">

                •    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | Type = 5      | Length        |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | Start.FGL                                     |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | Bits...
                     +-+-+-+-+-+-+-+-
                • </artwork>
              • </figure>
            • <t>
              • The TLV value consists of three bytes with the 24-bit starting FGL value N. This is followed by bytes with one bit per FGL. The high order bit of the first byte is for FGL N. The next-to-the-highest order bit is for FGL N+1. The low order bit of the first byte is for FGL N+7. The high order bit of the second byte, if there is a second byte, is for FGL N+8, and so on. If that bit is a one, the Address Flush message applies to that FGL. If that bit is a zero, then addresses that have been learned in that FGL are not flushed. Note that Length MUST be at least 3. If Length is 0, 1, or 2 for a Type 5 TLV, the TLV is corrupt and the Address Flush message MUST be discarded if tType 5 is implemented. FGLs do not wrap around. If there are enough bytes so that some bits correspond to an FGL higher than 0xFFFFFF, those bits are ignored, but the message is still processed for bits corresponding to valid FGLs.
              • </t>
            • </section>
          • <section title="All Data Labels" anchor="section-2.2.6" numbered="true" toc="default">
            • <t>
              • If the TLV Type is 6, the value is null as follows:
              • </t>
            • <figure title="" suppress-title="false" align="left" alt="" width="" height="">
              • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">

                •    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | Type = 6      | Length = 0    |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                • </artwork>
              • </figure>
            • <t>
              • This type is used when an RBridge wants to withdraw all addresses for all the Data Labels (all VLANs and FGLs). Length MUST be zero. If Length is any other value, the TLV is corrupt and the Address Flush message MUST be discarded.
              • </t>
            • </section>
          • <section title="MAC Address List" anchor="section-2.2.7" numbered="true" toc="default">
            • <t>
              • If the TLV Type is 7, the value is a list of MAC addresses as follows:
              • </t>
            • <figure title="" suppress-title="false" align="left" alt="" width="" height="">
              • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">

                •    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | Type = 7      | Length        |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC 1 upper half                              |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC 1 lower half                              |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC 2 upper half                              |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC 2 lower half                              |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC ... upper half                            |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC ... lower half                            |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                • </artwork>
              • </figure>
            • <t>
              • The TLV value consists of a list of 48-bit MAC addresses. Length MUST be a multiple of 6. If it is not, the TLV is corrupt, and the Address Flush message MUST be discarded if the receiving RBridge implements Type 7.
              • </t>
            • </section>
          • <section title="MAC Address Blocks" anchor="section-2.2.8" numbered="true" toc="default">
            • <t>
              • If the TLV Type is 8, the value is a list of blocks of MAC addresses as follows:
              • </t>
            • <figure title="" suppress-title="false" align="left" alt="" width="" height="">
              • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">

                •    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | Type = 8      | Length        |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC.start 1 upper half                        |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC.start 1 lower half                        |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC.end 1 upper half                          |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC.end 1 lower half                          |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC.start 2 upper half                        |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC.start 2 lower half                        |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC.end 2 upper half                          |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC.end 2 lower half                          |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC.start ... upper half                      |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC.start ... lower half                      |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC.end ... upper half                        |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     | MAC.end ... lower half                        |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                • </artwork>
              • </figure>
            • <t>
              • The TLV value consists of sets of Start.MAC and End.MAC numbers. The Address Flush information applies to the 48-bit MAC Addresses in that range, inclusive. A single MAC address is indicated by setting both Start.MAC and End.MAC to the same value. If End.MAC is less than Start.MAC, considering them as unsigned integers, that block is ignored but the Address Flush message is still processed for any other blocks present. For this Type, Length MUST be a multiple of 12; if it is not, the TLV is corrupt and the Address Flush message MUST be discarded if the receiving RBridge implements Type 7.
              • </t>
            • </section>
          • </section>
        • </section>
      • <section title="IANA Considerations" anchor="section-3" numbered="true" toc="default">
        • <section title="Address Flush RBridge Channel Protocol Number" anchor="section-3.1" numbered="true" toc="default">
          • <t>
            • IANA has assigned 0x009 as the Address Flush RBridge Channel Protocol number from the range of RBridge Channel protocols allocated by Standards Action <xref target="RFC7178" format="default" pageno="false"/> <xref target="RFC8126" format="default" pageno="false"/>..
            • </t>
          • <t>
            • The added entry to the "RBridge Channel Protocols" registry at <https://www.iana.org/assignments/trill-parameters/> is as follows:
            • </t>
          • <figure title="" suppress-title="false" align="left" alt="" width="" height="">
            • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">

              •       Protocol  Description       Reference
                      --------  --------------    ------------------
                        0x009    Address Flush     [RFC8383]
              • </artwork>
            • </figure>
          • </section>
        • <section title="TRILL Address Flush TLV Types" anchor="section-3.2" numbered="true" toc="default">
          • <t>
            • IANA has created the "TRILL Address Flush TLV Types" registry at <https://www.iana.org/assignments/trill-parameters/> as a subregistry of the "RBridge Channel Protocols" registry.
            • <-- [rfced] Please review our update to the description of the relationship between the "RBridge Channel Protocols" registry and the "TRILL Address Flush TLV Types" registry (i.e., please confirm that the latter is a subregistry).   -->
            • Registry headers are as below. The initial entries are as in the table in <xref target="section-2.2" format="default" pageno="false"/>..
            • IANA has created the "TRILL Address Flush TLV Types" registry at <https://www.iana.org/assignments/trill-parameters/> as a subregistry of the "RBridge Channel Protocols" registry. Registry headers are as below. The initial entries are as in the table in <xref target="section-2.2" format="default" pageno="false"/>..
            • </t>
          • <figure title="" suppress-title="false" align="left" alt="" width="" height="">
            • <artwork {http://www.w3.org/XML/1998/namespace}space="preserve" name="" type="" align="left" alt="" width="" height="">

              •       Registry:  TRILL Address Flush TLV Types
                      Registration Procedures: IETF Review
                      Reference:  [RFC8383]
              • </artwork>
            • </figure>
          • </section>
        • </section>
      • <section title="Security Considerations" anchor="section-4" numbered="true" toc="default">
        • <t>
          • The Address Flush RBridge Channel Protocol itself provides no security assurances or features. However, Address Flush protocol messages can be secured by use of the RBridge Channel Header Extension <xref target="RFC7978" format="default" pageno="false"/>. It is RECOMMENDED that all RBridges that implement the address fAddress Flush message be configured to ignore such messages unless they have been secured with an RBridge Channel Header Extension that meets local security policy.. It is RECOMMENDED that all RBridges that implement the address fAddress Flush message be configured to ignore such messages unless they have been secured with an RBridge Channel Header Extension that meets local security policy.
          • </t>
        • <t>
          • If RBridges receiving Address Flush messages do not require them to be at least authenticated, they are relatively easy to forge. In that case, such forged Address Flush messages can reduce network efficiency, by purging useful learned information that will have to be relearned. This provides a denial-of-service attack, but cannot cause incorrect operation in the sense that it cannot cause a frame to be improperly delivered.
          • </t>
        • <t>
          • See <xref target="RFC7178" format="default" pageno="false"/> for general RBridge Channel Security Considerations. for general RBridge Channel Security Considerations.
          • </t>
        • <t>
          • See <xref target="RFC6325" format="default" pageno="false"/> for general TRILL Security Considerations. for general TRILL Security Considerations.
          • </t>
        • </section>
      • </middle>
    • <back>
      • <references title="Normative References">
        • <reference anchor="RFC2119" target="https://www.rfc-editor.org/info/rfc2119">
          • <front>
            • <title>
              • Key words for use in RFCs to Indicate Requirement Levels
              • </title>
            • <author initials="S." surname="Bradner" fullname="S. Bradner">
              • <organization/>
              • </author>
            • <date year="1997" month="March"/>
            • <abstract>
              • <t>
                • In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.
                • </t>
              • </abstract>
            • </front>
          • <seriesInfo name="BCP" value="14"/>
          • <seriesInfo name="RFC" value="2119"/>
          • <seriesInfo name="DOI" value="10.17487/RFC2119"/>
          • </reference>
        • <reference anchor="RFC6325" target="https://www.rfc-editor.org/info/rfc6325">
          • <front>
            • <title>
              • Routing Bridges (RBridges): Base Protocol Specification
              • </title>
            • <author initials="R." surname="Perlman" fullname="R. Perlman">
              • <organization/>
              • </author>
            • <author initials="D." surname="Eastlake 3rd" fullname="D. Eastlake 3rd">
              • <organization/>
              • </author>
            • <author initials="D." surname="Dutt" fullname="D. Dutt">
              • <organization/>
              • </author>
            • <author initials="S." surname="Gai" fullname="S. Gai">
              • <organization/>
              • </author>
            • <author initials="A." surname="Ghanwani" fullname="A. Ghanwani">
              • <organization/>
              • </author>
            • <date year="2011" month="July"/>
            • <abstract>
              • <t>
                • Routing Bridges (RBridges) provide optimal pair-wise forwarding without configuration, safe forwarding even during periods of temporary loops, and support for multipathing of both unicast and multicast traffic. They achieve these goals using IS-IS routing and encapsulation of traffic with a header that includes a hop count.
                • </t>
              • <t>
                • RBridges are compatible with previous IEEE 802.1 customer bridges as well as IPv4 and IPv6 routers and end nodes. They are as invisible to current IP routers as bridges are and, like routers, they terminate the bridge spanning tree protocol.
                • </t>
              • <t>
                • The design supports VLANs and the optimization of the distribution of multi-destination frames based on VLAN ID and based on IP-derived multicast groups. It also allows unicast forwarding tables at transit RBridges to be sized according to the number of RBridges (rather than the number of end nodes), which allows their forwarding tables to be substantially smaller than in conventional customer bridges. [STANDARDS-TRACK]
                • </t>
              • </abstract>
            • </front>
          • <seriesInfo name="RFC" value="6325"/>
          • <seriesInfo name="DOI" value="10.17487/RFC6325"/>
          • </reference>
        • <reference anchor="RFC7172" target="https://www.rfc-editor.org/info/rfc7172">
          • <front>
            • <title>
              • Transparent Interconnection of Lots of Links (TRILL): Fine-Grained Labeling
              • </title>
            • <author initials="D." surname="Eastlake 3rd" fullname="D. Eastlake 3rd">
              • <organization/>
              • </author>
            • <author initials="M." surname="Zhang" fullname="M. Zhang">
              • <organization/>
              • </author>
            • <author initials="P." surname="Agarwal" fullname="P. Agarwal">
              • <organization/>
              • </author>
            • <author initials="R." surname="Perlman" fullname="R. Perlman">
              • <organization/>
              • </author>
            • <author initials="D." surname="Dutt" fullname="D. Dutt">
              • <organization/>
              • </author>
            • <date year="2014" month="May"/>
            • <abstract>
              • <t>
                • The IETF has standardized Transparent Interconnection of Lots of Links (TRILL), a protocol for least-cost transparent frame routing in multi-hop networks with arbitrary topologies and link technologies, using link-state routing and a hop count. The TRILL base protocol standard supports the labeling of TRILL Data packets with up to 4K IDs. However, there are applications that require a larger number of labels providing configurable isolation of data. This document updates RFC 6325 by specifying optional extensions to the TRILL base protocol to safely accomplish this. These extensions, called fine-grained labeling, are primarily intended for use in large data centers, that is, those with more than 4K users requiring configurable data isolation from each other.
                • </t>
              • </abstract>
            • </front>
          • <seriesInfo name="RFC" value="7172"/>
          • <seriesInfo name="DOI" value="10.17487/RFC7172"/>
          • </reference>
        • <reference anchor="RFC7178" target="https://www.rfc-editor.org/info/rfc7178">
          • <front>
            • <title>
              • Transparent Interconnection of Lots of Links (TRILL): RBridge Channel Support
              • </title>
            • <author initials="D." surname="Eastlake 3rd" fullname="D. Eastlake 3rd">
              • <organization/>
              • </author>
            • <author initials="V." surname="Manral" fullname="V. Manral">
              • <organization/>
              • </author>
            • <author initials="Y." surname="Li" fullname="Y. Li">
              • <organization/>
              • </author>
            • <author initials="S." surname="Aldrin" fullname="S. Aldrin">
              • <organization/>
              • </author>
            • <author initials="D." surname="Ward" fullname="D. Ward">
              • <organization/>
              • </author>
            • <date year="2014" month="May"/>
            • <abstract>
              • <t>
                • This document specifies a general channel mechanism for sending messages, such as Bidirectional Forwarding Detection (BFD) messages, between Routing Bridges (RBridges) and between RBridges and end stations in an RBridge campus through extensions to the Transparent Interconnection of Lots of Links (TRILL) protocol.
                • </t>
              • </abstract>
            • </front>
          • <seriesInfo name="RFC" value="7178"/>
          • <seriesInfo name="DOI" value="10.17487/RFC7178"/>
          • </reference>
        • <reference anchor="RFC7780" target="https://www.rfc-editor.org/info/rfc7780">
          • <front>
            • <title>
              • Transparent Interconnection of Lots of Links (TRILL): Clarifications, Corrections, and Updates
              • </title>
            • <author initials="D." surname="Eastlake 3rd" fullname="D. Eastlake 3rd">
              • <organization/>
              • </author>
            • <author initials="M." surname="Zhang" fullname="M. Zhang">
              • <organization/>
              • </author>
            • <author initials="R." surname="Perlman" fullname="R. Perlman">
              • <organization/>
              • </author>
            • <author initials="A." surname="Banerjee" fullname="A. Banerjee">
              • <organization/>
              • </author>
            • <author initials="A." surname="Ghanwani" fullname="A. Ghanwani">
              • <organization/>
              • </author>
            • <author initials="S." surname="Gupta" fullname="S. Gupta">
              • <organization/>
              • </author>
            • <date year="2016" month="February"/>
            • <abstract>
              • <t>
                • Since the publication of the TRILL (Transparent Interconnection of Lots of Links) base protocol in 2011, active development and deployment of TRILL have revealed errata in RFC 6325 and areas that could use clarifications or updates. RFC 7177, RFC 7357, and an intended replacement of RFC 6439 provide clarifications and updates with respect to adjacency, the TRILL ESADI (End Station Address Distribution Information) protocol, and Appointed Forwarders, respectively. This document provides other known clarifications, corrections, and updates. It obsoletes RFC 7180 (the previous "TRILL clarifications, corrections, and updates" RFC), and it updates RFCs 6325, 7177, and 7179.
                • </t>
              • </abstract>
            • </front>
          • <seriesInfo name="RFC" value="7780"/>
          • <seriesInfo name="DOI" value="10.17487/RFC7780"/>
          • </reference>
        • <reference anchor="RFC7978" target="https://www.rfc-editor.org/info/rfc7978">
          • <front>
            • <title>
              • Transparent Interconnection of Lots of Links (TRILL): RBridge Channel Header Extension
              • </title>
            • <author initials="D." surname="Eastlake 3rd" fullname="D. Eastlake 3rd">
              • <organization/>
              • </author>
            • <author initials="M." surname="Umair" fullname="M. Umair">
              • <organization/>
              • </author>
            • <author initials="Y." surname="Li" fullname="Y. Li">
              • <organization/>
              • </author>
            • <date year="2016" month="September"/>
            • <abstract>
              • <t>
                • The IETF TRILL (Transparent Interconnection of Lots of Links) protocol includes an optional mechanism (specified in RFC 7178) called RBridge Channel for the transmission of typed messages between TRILL switches in the same campus and the transmission of such messages between TRILL switches and end stations on the same link. This document specifies extensions to the RBridge Channel protocol header to support two features as follows: (1) a standard method to tunnel payloads whose type can be indicated by Ethertype through encapsulation in RBridge Channel messages; and (2) a method to support security facilities for RBridge Channel messages. This document updates RFC 7178.
                • </t>
              • </abstract>
            • </front>
          • <seriesInfo name="RFC" value="7978"/>
          • <seriesInfo name="DOI" value="10.17487/RFC7978"/>
          • </reference>
        • <reference anchor="RFC8174" target="https://www.rfc-editor.org/info/rfc8174">
          • <front>
            • <title>
              • Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words
              • </title>
            • <author initials="B." surname="Leiba" fullname="B. Leiba">
              • <organization/>
              • </author>
            • <date year="2017" month="May"/>
            • <abstract>
              • <t>
                • RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings.
                • </t>
              • </abstract>
            • </front>
          • <seriesInfo name="BCP" value="14"/>
          • <seriesInfo name="RFC" value="8174"/>
          • <seriesInfo name="DOI" value="10.17487/RFC8174"/>
          • </reference>
        • </references>
      • <references title="Informative References">
        • <reference anchor="RFC4762" target="https://www.rfc-editor.org/info/rfc4762">
          • <front>
            • <title>
              • Virtual Private LAN Service (VPLS) Using Label Distribution Protocol (LDP) Signaling
              • </title>
            • <author initials="M." surname="Lasserre" fullname="M. Lasserre" role="editor">
              • <organization/>
              • </author>
            • <author initials="V." surname="Kompella" fullname="V. Kompella" role="editor">
              • <organization/>
              • </author>
            • <date year="2007" month="January"/>
            • <abstract>
              • <t>
                • This document describes a Virtual Private LAN Service (VPLS) solution using pseudowires, a service previously implemented over other tunneling technologies and known as Transparent LAN Services (TLS). A VPLS creates an emulated LAN segment for a given set of users; i.e., it creates a Layer 2 broadcast domain that is fully capable of learning and forwarding on Ethernet MAC addresses and that is closed to a given set of users. Multiple VPLS services can be supported from a single Provider Edge (PE) node.
                • </t>
              • <t>
                • This document describes the control plane functions of signaling pseudowire labels using Label Distribution Protocol (LDP), extending RFC 4447. It is agnostic to discovery protocols. The data plane functions of forwarding are also described, focusing in particular on the learning of MAC addresses. The encapsulation of VPLS packets is described by RFC 4448. [STANDARDS-TRACK]
                • </t>
              • </abstract>
            • </front>
          • <seriesInfo name="RFC" value="4762"/>
          • <seriesInfo name="DOI" value="10.17487/RFC4762"/>
          • </reference>
        • <reference anchor="RFC8126" target="https://www.rfc-editor.org/info/rfc8126">
          • <front>
            • <title>
              • Guidelines for Writing an IANA Considerations Section in RFCs
              • </title>
            • <author initials="M." surname="Cotton" fullname="M. Cotton">
              • <organization/>
              • </author>
            • <author initials="B." surname="Leiba" fullname="B. Leiba">
              • <organization/>
              • </author>
            • <author initials="T." surname="Narten" fullname="T. Narten">
              • <organization/>
              • </author>
            • <date year="2017" month="June"/>
            • <abstract>
              • <t>
                • Many protocols make use of points of extensibility that use constants to identify various protocol parameters. To ensure that the values in these fields do not have conflicting uses and to promote interoperability, their allocations are often coordinated by a central record keeper. For IETF protocols, that role is filled by the Internet Assigned Numbers Authority (IANA).
                • </t>
              • <t>
                • To make assignments in a given registry prudently, guidance describing the conditions under which new values should be assigned, as well as when and how modifications to existing values can be made, is needed. This document defines a framework for the documentation of these guidelines by specification authors, in order to assure that the provided guidance for the IANA Considerations is clear and addresses the various issues that are likely in the operation of a registry.
                • </t>
              • <t>
                • This is the third edition of this document; it obsoletes RFC 5226.
                • </t>
              • </abstract>
            • </front>
          • <seriesInfo name="BCP" value="26"/>
          • <seriesInfo name="RFC" value="8126"/>
          • <seriesInfo name="DOI" value="10.17487/RFC8126"/>
          • </reference>
        • </references>
      • <section title="Acknowledgements" numbered="no" anchor="acknowledgements" toc="default">
        • <t>
          • <list style="hanging" hangIndent="3">
            • <t hangText="The following are thanked for their contributions:">
              • <vspace blankLines="1"/> Ramkumar Parameswaran, Henning Rogge Ramkumar Parameswaran, Henning Rogge
              • </t>
            • </list>
          • </t>
        • <-- [rfced] Throughout the text, the following terminology appears to be used inconsistently.  Please review these occurrences and let us know if/how they may be made consistent.  RBridge Channel messages vs. RBridge Channel protocol message Address Flush message vs. address flush messages vs. address flush Message type # vs. Type # (e.g., type 6 vs. Type 6) length bypte vs. Length byte  -->
        • </section>
      • </back>
    • </rfc>
1<?xml version='1.0' encoding='us-ascii'?>
2<!DOCTYPE rfc SYSTEM "rfc2629.dtd">
3
4<rfc submissionType="IETF" category="std" consensus="yes" number='8383'>
5  <?rfc compact="yes"?>
6 <?rfc text-list-symbols="-o*+"?>
7 <?rfc subcompact="no"?>
8 <?rfc sortrefs="yes"?>
9 <?rfc symrefs="yes"?>
10 <?rfc strict="yes"?>
11 <?rfc toc="yes"?>
12 <front>
13   <title abbrev="TRILL Address Flush Message">Transparent Interconnection of Lots of Links (TRILL): Address&nbsp;Flush&nbsp;Message</title>
14   
15   <author fullname="Weiguo Hao" initials="W." surname="Hao">
16     
17 <organization abbrev="Huawei">Huawei Technologies</organization>
18 <address><postal><street>101 Software Avenue,</street>
19 <street>Nanjing 210012</street>
20 <street>China</street>
21 </postal>
22 <phone>+86-25-56623144</phone>
23 <email>haoweiguo@huawei.com</email>
24 </address>
25   </author>
26   <author fullname="Donald Easlake 3rd" initials="D." surname="Eastlake, 3rd">
27     <organization abbrev="Huawei">Huawei Technologies</organization>
28     <address><postal><street>155 Beaver Street</street><street>Milford, MA 01757</street>
29     <street>United States of America</street></postal>
30     <phone>+1-508-333-2270</phone>
31     <email>d3e3e3@gmail.com</email>
32     </address>
33   </author>
34
35 <author fullname="Yizhou Li" initials="Y." surname="Li">
36 <organization abbrev="Huawei">Huawei Technologies</organization>
37 <address><postal><street>101 Software Avenue,</street>
38 <street>Nanjing 210012</street>
39 <street>China</street>
40 </postal>
41 <phone>+86-25-56624629</phone>
42 <email>liyizhou@huawei.com</email>
43 </address>
44 </author>
45
46 <author fullname="Mohammed Umair" initials="M." surname="Umair">
47 <organization>Cisco</organization>
48 <address><postal><street>Cessna Business Park, Kadubeesanahalli Village, Hobli,</street>
49 <street>Sarjapur, Varthur Main Road, Marathahalli,</street>
50 <street>Bengaluru, Karnataka 560087</street>
51 <street>India</street>
52 </postal>
53 <email>mohammed.umair2@gmail.com</email>
54 </address>
55 </author>
56
57 <date month="May" year="2018"/>
58 <workgroup>TRILL Working Group</workgroup>
59
60
61<abstract>
62  <t> The TRILL (Transparent Interconnection of Lots
63 of Links) protocol, by default, learns end station addresses
64 from observing the data plane.  In particular, it learns local
65 Media Access Control (MAC) addresses and the edge switch port of
66 attachment from the receipt of local data frames and learns
67 remote MAC addresses and the edge switch port of attachment from the
68 decapsulation of remotely sourced TRILL Data packets.</t>
69
70 <t>
71   This document specifies a message by which a TRILL switch can
72   explicitly request other TRILL switches to flush certain MAC
73   reachability learned through the decapsulation of TRILL Data packets.
74   This is a supplement to the TRILL automatic address forgetting (see Section 4.8.3 of <xref target="RFC6325"/>) and
75   can assist in achieving more rapid convergence in case of topology or
76   configuration change.</t>
77
78 </abstract>
79 </front>
80
81 <middle>
82 <section title="Introduction" anchor="section-1"><t>
83   By default, edge TRILL (Transparent Interconnection of Lots of Links) switches
84   <xref target="RFC6325"/> <xref target="RFC7780"/>, also called edge Routing Bridges (RBridges), learn end
85   station MAC address reachability from observing the data plane. On
86   receipt of a native frame from an end station, they would learn the
87   local MAC address attachment of the source end station. And on
88   egressing (decapsulating) a remotely originated TRILL Data packet,
89   they learn the remote MAC address and remote attachment TRILL switch.
90   Such learning is all scoped by data label (VLAN or Fine-Grained Label (FGL)
91   <xref target="RFC7172"/>).</t>
92
93 <t>
94   TRILL has mechanisms for timing out such learning and appropriately
95   clearing it based on some network connectivity and configuration
96   changes; however, there are circumstances under which it would be
97   helpful for a TRILL switch to be able to explicitly flush (purge)
98   certain learned end station reachability information in remote
99   RBridges to achieve more-rapid convergence.  Section 6.2 of <xref target="RFC4762"/>
100   is an example of the use of such a mechanism.</t>
101
102 <t>
103   Another example, based on Appendix A.3 of <xref target="RFC6325"/> ("Wiring Closet Topology"), presents a bridged LAN connected to a TRILL network via
104   multiple RBridge ports. For optimum paths, Appendix A.3.3 suggests
105   configuring the RBridge ports to be like one Spanning Tree Protocol
106   (STP) tree root in the bridged LAN. The Address Flush message in this
107   document could also be triggered in this case when one of the edge
108   RBridges receives Topology Change (TC) information (e.g., TC 
109   in STP, Topology Change Notification (TCN) in Multiple
110   Spanning Tree Protocol (MSTP) in order to rapidly flush the MAC addresses
111   for specific VLANs learned at the other edge RBridge ports.</t>
112
113 <t>
114   A TRILL switch can easily flush any locally learned addresses it
115   wants. This document specifies an RBridge Channel Support protocol <xref
116   target="RFC7178"/> message to request flushing address information
117   for specific VLANs or FGLs (<xref target="RFC7172"/>) learned from decapsulating TRILL Data
118   packets.</t>
119
120   <section title="Terminology and Abbreviations" anchor="section-1.1">
121
122     <t> The key words "MUST", "MUST NOT",
123 "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT",
124 "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to
125 be interpreted as described in <xref target="RFC2119"/> <xref
126 target="RFC8174"/> when, and only when, they appear in all
127 capitals, as shown here.</t>
128
129 <t>
130   This document uses the terms and abbreviations defined in <xref
131   target="RFC6325"/> and <xref target="RFC7978"/> as well as the
132   following:</t>
133
134 <t><list hangIndent="3" style="hanging"><t hangText="Data Label:">A VLAN or FGL</t>
135
136         <t hangText="Edge TRILL Switch:">A TRILL switch attached to one or more links that provide end station service
137 </t>
138
139      <t hangText="FCS:">Frame Check Sequence</t>
140
141      <t hangText="FGL:">Fine-Grained Label <xref target="RFC7172"/></t>
142
143<t hangText="Management VLAN:"> A VLAN in which all TRILL switches in a campus
144 indicate interest so that multi-destination TRILL Data packets,
145         including RBridge Channel protocol messages <xref target="RFC7978"/>, sent with that
146         VLAN as the Inner.VLAN will be delivered to all TRILL switches
147         in the campus. Usually, no end station service is offered in the
148         Management VLAN.
149 </t>
150
151
152
153      <t hangText="MAC:">Media Access Control</t>
154
155      <t hangText="RBridge:">An alternative name for a TRILL switch</t>
156
157      <t hangText="STP:">Spanning Tree Protocol</t>
158
159      <t hangText="TC:">Topology Change message</t>
160
161      <t hangText="TCN:">Topology Change Notification message</t>
162
163<t hangText="TRILL switch:">A device implementing the TRILL protocol RFC 6235
164 <xref target="RFC7780"/>
165 </t>
166
167 </list>
168 </t>
169
170 </section>
171
172 </section>
173
174 <section title="Address Flush Message Details" anchor="section-2"><t>
175   The Address Flush message is an RBridge Channel protocol message
176   <xref target="RFC7178"/>.</t>
177
178 <t>
179   The general structure of an RBridge Channel packet on a link between
180   TRILL switches is shown in <xref target="ref-rbridge-channel-protocol-message-structure"/>. The Protocol field in the
181   RBridge Channel Header gives the type of RBridge Channel packet and
182   indicates how to interpret the Channel-Protocol-Specific Payload
183   <xref target="RFC7178"/>.
184 </t>
185
186<figure title="RBridge Channel Protocol Message Structure" anchor="ref-rbridge-channel-protocol-message-structure"><artwork><![CDATA[
187
188                   +-----------------------------------+
189                   |            Link Header            |
190                   +-----------------------------------+
191                   |            TRILL Header           |
192                   +-----------------------------------+
193                   |      Inner Ethernet Addresses     |
194                   +-----------------------------------+
195                   |      Data Label (VLAN or FGL)     |
196                   +-----------------------------------+
197                   |       RBridge Channel Header      |
198                   +-----------------------------------+
199                   | Channel-Protocol-Specific Payload |
200                   +-----------------------------------+
201                   |   Link Trailer (FCS if Ethernet)  |
202                   +-----------------------------------+
203]]></artwork>
204 </figure>
205
206 <t>
207   By default, an Address Flush RBridge Channel protocol message applies to
208   addresses within the Data Label that appear right after the Inner
209   Ethernet Addresses.  Address Flush protocol messages are usually sent
210   as multi-destination packets (TRILL Header M bit equal to one) so as
211   to reach all TRILL switches offering end station service in the VLAN
212   or FGL specified by that Data Label. Both multi-destination and
213   unicast Address Flush messages SHOULD be sent at priority 6 since
214   they are important control messages but are lower priority than
215   control messages that establish or maintain adjacency.</t>
216
217 <t>
218   Nevertheless:</t>
219
220   <t><list style="symbols">
221
222     <t>There are provisions for optionally indicating the Data Label(s)
223      to be flushed for cases where the Address Flush message is sent
224      over a Management VLAN or the like.</t>
225
226 <t>An Address Flush message can be sent unicast, if it is desired to
227      clear addresses at one TRILL switch only.</t>
228
229 <t>An Address Flush message can be sent selectively to the RBridges
230      that have at least one access port configured as one of the VLANs or
231      FGLs specified in the Address Flush message payload.</t>
232
233 </list>
234 </t>
235
236 <t>
237   Implementations should consider logging Address Flush messages
238   received with appropriate protections against packet storms.</t>
239
240   <section title="VLAN Block Only Case" anchor="section-2.1">
241
242     <t>
243   <xref target="ref-address-flush-message-vlan-block-case"/> expands
244   the RBridge Channel Header and Channel-Protocol-Specific Payload
245   from <xref
246   target="ref-rbridge-channel-protocol-message-structure"/> for the
247   case of the VLAN-only-based Address Flush message. This form of the
248   Address Flush message is optimized for flushing MAC addresses based
249   on nickname and blocks of VLANs. 0x8946 is the Ethertype assigned
250     by IEEE for the RBridge Channel protocol.</t>
251
252<!--[rfced] Would a pointer to an IEEE registry be needed/wanted by the reader or others?  If so, please let us know how to update.
253
254Original:
255 0x8946 is the Ethertype assigned by IEEE for the RBridge Channel protocol
256
257-->
258
259 <figure title="Address Flush Message - VLAN Block Case" anchor="ref-address-flush-message-vlan-block-case"><artwork><![CDATA[
260    0                   1                   2                   3
261    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
262RBridge Channel Header:
263   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
264   |    RBridge-Channel (0x8946)   |  0x0  |Channel Protocol= 0x009|
265   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
266   |          Flags        |  ERR  |
267   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
268Address Flush Protocol Specific:
269   +-+-+-+-+-+-+-+-+
270   | K-nicks       |
271   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
272   | Nickname 1                    | Nickname 2                    |
273   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
274   | Nickname ...                  | Nickname K-nicks              |
275   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
276   | K-VLBs        |
277   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
278   | RESV  | Start.VLAN 1          | RESV  | End.VLAN 1            |
279   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
280   | RESV  | Start.VLAN 2          | RESV  | End.VLAN 2            |
281   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
282   | RESV  | Start.VLAN ...        | RESV  | End.VLAN ...          |
283   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
284   | RESV  | Start.VLAN K-VLBs     | RESV  | End.VLAN K-VLBs       |
285   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
286]]></artwork>
287 </figure>
288 <t>
289   The fields in <xref target="ref-address-flush-message-vlan-block-case"/> related to the Address Flush message are as
290   follows:</t>
291
292 <t><list style="hanging" hangIndent="3">
293 <t hangText="Channel Protocol:">
294 The RBridge Channel Protocol value allocated
295 for Address Flush (see <xref target="section-3"/>).
296 </t>
297
298 <t hangText="K-nicks:">The number of nicknames listed as an unsigned
299 integer. If this is zero, the ingress nickname in the TRILL
300         Header <xref target="RFC6325"/> is considered to be the only nickname to which
301         the message applies. If non-zero, it gives the number of
302         nicknames listed right after K-nicks to which the message
303         applies, and, in this non-zero case, the flush does not apply to
304         the ingress nickname in the TRILL Header unless it is also
305         listed. The message flushes address learning due to egressing
306         TRILL Data packets that had an ingress nickname to which the
307         message applies.
308 </t>
309
310 <t hangText="Nickname:">A listed nickname to which it is intended that the Address Flush message apply.  If an unknown or reserved
311         nickname occurs in the list, it is ignored, but the address
312         flush operation is still executed with the other nicknames. If
313         an incorrect nickname occurs in the list, so that some address
314         learning is flushed that should not have been flushed, the
315         network will still operate correctly; however, it will be less efficient
316         as the incorrectly flushed learning is relearned.
317 </t>
318
319 <t hangText="K-VLBs:">The number of VLAN blocks present as an unsigned
320 integer. If this byte is zero, the message is the more general
321         format specified in <xref target="section-2.2"/>. If it is non-zero, it gives
322         the number of blocks of VLANs present. Thus, in the VLAN Block
323         address flush case, K-VLBs will be at least one.
324 </t>
325
326 <t hangText="RESV:">4 reserved bits. MUST be sent as zero and ignored on
327 receipt.
328 </t>
329
330 <t hangText="Start.VLAN, End.VLAN:">These 12-bit fields give the beginning and
331 ending VLAN IDs of a block of VLANs. The block includes both
332         the starting and ending values; so, a block of size one is
333         indicated by setting End.VLAN equal to Start.VLAN. If
334         Start.VLAN is 0x000, it is treated as if it was 0x001. If
335         End.VLAN is 0xFFF, it is treated as if it was 0xFFE. If
336         End.VLAN is smaller than Start.VLAN, considering both as
337         unsigned integers, that VLAN block is ignored, but the address
338         flush operation is still executed with other VLAN blocks in the
339         message.  VLAN blocks may overlap, in which case, the address
340         flush operation is applicable to a VLAN covered by any one or
341         more of the blocks in the message.
342 </t>
343
344 </list>
345 </t>
346
347
348 <t>
349   This message flushes all addresses in an applicable VLAN learned from
350   egressing TRILL Data packets with an applicable nickname as ingress.
351   To flush addresses for all VLANs, it is easy to specify a block
352   covering all valid VLAN IDs (i.e., from 0x001 to 0xFFE).</t>
353
354 </section>
355
356 <section title="Extensible Case" anchor="section-2.2"><t>
357   A more general form of the Address Flush message is provided to
358   support flushing by FGL and more efficient encodings of VLANs and
359   FGLs where using a set of contiguous blocks is cumbersome. It also
360   supports optionally specifying the MAC addresses to clear. This form
361   is extensible.</t>
362
363 <t>
364   The extensible case is indicated by a zero in the byte shown in
365   <xref target="ref-address-flush-message-vlan-block-case"/> as "K-VLBs" followed by other information encoded as TLVs.</t>
366
367 <figure title="Address Flush Message - Extensible Case" anchor="ref-address-flush-message-extensible-case"><artwork><![CDATA[
368    0                   1                   2                   3
369    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
370RBridge Channel Header:
371   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
372   |    RBridge-Channel (0x8946)   |  0x0  |Channel Protocol=0x009 |
373   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
374   |          Flags        |  ERR  |
375   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
376Address Flush Protocol Specific:
377   +-+-+-+-+-+-+-+-+
378   | K-nicks       |
379   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
380   | Nickname 1                    | Nickname 2                    |
381   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
382   | Nickname ...                  | Nickname K-nicks              |
383   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
384   | 0             |  TLVs ...
385   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...
386]]></artwork>
387 </figure>
388
389 <t><list style="hanging" hangIndent="3"><t hangText="Channel Protocol, K-nicks, Nickname:">These fields are as specified
390 in <xref target="section-2.1"/>.
391 </t>
392
393 <t hangText="TLVs:">If the byte immediately before the TLVs field, which is the byte labeled "K-VLBs" in <xref target="ref-address-flush-message-vlan-block-case"/>, is zero, as shown in <xref target="ref-address-flush-message-extensible-case"/>, the remainder of the message consists of TLVs encoded as
394         shown in <xref target="ref-type-length-value"/>.
395 </t>
396
397 </list>
398 </t>
399
400
401
402 <figure title="Type, Length, Value" anchor="ref-type-length-value"><artwork><![CDATA[
403          0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
404         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
405         |  Type         |  Length       |  Value
406         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
407]]></artwork>
408 </figure>
409
410 <t><list style="hanging" hangIndent="3"><t hangText="Type:">The 8-bit TLV type as shown in the table below. See
411 subsections of <xref target="section-2.2"/> for details on each type
412         assigned below. If the type is reserved or not known by a
413         receiving RBridge, that receiving RBridge ignores the value and
414         skips to the next TLV by use of the Length byte. There is no
415         provision for a list of VLAN ID TLVs as there are few enough of
416         them that an arbitrary subset of VLAN IDs can be represented as
417         a bit map.
418 </t>
419
420 </list>
421 </t>
422
423
424 <figure><artwork><![CDATA[
425             Type       Description       Reference
426            ------   ------------------  -----------------
427                0     Reserved            [RFC8383]
428                1     Blocks of VLANs     [RFC8383]
429                2     Bit Map of VLANs    [RFC8383]
430                3     Blocks of FGLs      [RFC8383]
431                4     List of FGLs        [RFC8383]
432                5     Bit Map of FGLs     [RFC8383]
433                6     All Data Labels     [RFC8383]
434                7     MAC Address List    [RFC8383]
435                8     MAC Address Blocks  [RFC8383]
436            9-254     Unassigned
437              255     Reserved            [RFC8383]
438]]></artwork>
439 </figure>
440
441 <t><list style="hanging" hangIndent="3"><t hangText="Length:">The 8-bit unsigned integer length in bytes of the
442 remaining information in the TLV after the Length byte. The
443         Length MUST NOT imply that the value extends beyond the end of the
444         RBridge Channel-Protocol-Specific Payload area. If it does, the
445         Address Flush message is corrupt and MUST be ignored.
446 </t>
447
448 </list>
449 </t>
450
451
452
453 <t><list hangIndent="3" style="hanging"><t hangText="Value:">Depends on the TLV type.</t>
454
455 </list>
456 </t>
457
458 <t>
459   In an extensible Address Flush message, when the TLVs are parsed,
460   those TLVs having unknown types are ignored by the receiving RBridge.
461   There may be multiple instances of TLVs with the same Type in the
462   same Address Flush message, and TLVs are not required to be in any
463   particular order.</t>
464
465 <t><list style="symbols"><t>All RBridges implementing the Address Flush RBridge Channel protocol
466      message MUST implement types 1 and 2, the VLAN types, and Type 6,
467      which indicates addresses are to be flushed for all Data Labels.</t>
468
469 <t>RBridges that implement the Address Flush message and implement
470      FGL ingress/egress MUST implement types 3, 4, and 5, the FGL
471      types. (An RBridge that is merely FGL safe <xref target="RFC7172"/>, but cannot
472      egress FGL TRILL Data packets, SHOULD ignore the FGL types, as it
473      will not learn any FGL-scoped MAC addresses from the data plane.)</t>
474
475 <t>RBridges that implement the Address Flush message SHOULD implement
476      types 7 and 8 so that specific MAC addresses can be flushed. If
477      they do not, the effect will be to flush all MAC addresses for the
478      indicated Data Labels, which may be inefficient as any MAC
479      addresses not intended to be flushed will have to be relearned.</t>
480
481 </list>
482 </t>
483
484 <t>
485   The parsing of the TLVs by a receiving RBridge results in three pieces
486   of information:</t>
487
488 <t><list style="empty" hangIndent="3">
489 <t><list style="numbers"><t>a flag indicating whether one or more Type 6 TLVs (All Data
490         Labels) were encountered;</t>
491
492 <t>a set of Data Labels accumulated from VLAN and/or FGL
493         specifying TLVs in the message; and,</t>
494
495 <t>if the MAC address TLV types are implemented, a set of MAC
496         addresses accumulated from MAC-address-specifying TLVs in the
497         message.</t>
498
499 </list>
500 </t>
501
502 </list>
503 </t>
504
505 <t>
506   VLANs/FGLs might be indicated more than once due to overlapping
507   blocks or the like, and a VLAN/FGL is included in the above set of
508   VLANs/FGLs if it occurs in any TLV in the Address Flush message. A
509   MAC address might be indicated more than once due to overlapping
510   blocks or the like, and a particular MAC address is included in the above set of
511   MAC addresses if it occurs in any TLV in the Address Flush message.</t>
512
513 <t>
514   After the above information has been accumulated by parsing the TLVs,
515   three sets are derived as described below: a set of nicknames, a set
516   of Data Labels, and a set of MAC addresses. The address flush
517   operation at the receiver applies to the cross product of these
518   derived sets. That is, a { Data Label, MAC address, nickname } triple
519   is flushed if and only if the Data Label matches an element in the
520   derived set of Data Labels, the MAC address matches an element in the
521   derived set of MAC address, and the nickname matches an element in
522   the derived set of nicknames. In the case of Data Labels and MAC
523   addresses, a special value of the set, {ALL}, is permitted, which
524   matches all values.</t>
525
526   <figure><artwork><![CDATA[
527   The sets are derived as follows:
528   
529      Data Labels set:
530         If the Type 6 TLV has been encountered, the set is {ALL}, else,
531         if any Data Labels have been accumulated by processing Data
532            Label TLVs (Types 1, 2, 3, 4, and 5), the set is those
533            accumulated Data Labels, else,
534         the Data Labels set is null and the Address Flush message does
535            nothing.
536
537      MAC Addresses set:
538         In the receiver does not implement the MAC address types (Types
539            7 and 8) or it does implement those types but no MAC
540            addresses are accumulated in parsing the TLVs, then the MAC
541            Address set is {ALL},
542         else, the MAC Addresses set is the set of MAC addresses
543            accumulated in processing the TLVs.
544
545      Nicknames set:
546         If the K-nicks field in the Address Flush message was zero,
547            then the ingress nickname in the TRILL Header of the message
548            is the sole nickname set member, else,
549         the nicknames set members are the K-nicks nicknames listed in
550            the Address Flush message.
551]]></artwork>
552 </figure>
553
554 <t>
555   The various formats below are provided for encoding efficiency. A
556   block of values is most efficient when there are a number of
557   consecutive values. A bit map is most efficient if there are
558   scattered values within a limited range. And a list of single values
559   is most efficient if there are widely scattered values.</t>
560
561 <section title="Blocks of VLANs" anchor="section-2.2.1"><t>
562   If the TLV Type is 1, the value is a list of blocks of VLANs as
563   follows:</t>
564
565 <figure><artwork><![CDATA[
566   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
567   | Type = 1      | Length        |
568   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
569   | RESV  | Start.VLAN 1          | RESV  | End.VLAN 1            |
570   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
571   | RESV  | Start.VLAN 2          | RESV  | End.VLAN 2            |
572   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
573   | RESV  | Start.VLAN ...        | RESV  | End.VLAN ...          |
574   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
575]]></artwork>
576 </figure>
577 <t>
578   The meaning of Start.VLAN and End.VLAN is as specified in <xref target="section-2.1"/>. Length MUST be a multiple of 4. If Length is not a multiple of
579   4, the TLV is corrupt and the Address Flush message MUST be
580   discarded.</t>
581
582 </section>
583
584 <section title="Bit Map of VLANs" anchor="section-2.2.2"><t>If the TLV Type is 2, the value is a bit map of VLANs as follows:</t>
585
586 <figure><artwork><![CDATA[
587   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
588   | Type = 2      | Length        |
589   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
590   | RESV  | Start.VLAN            | Bits...
591   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
592]]></artwork>
593 </figure>
594 <t>
595   The value portion of the TLV begins with two bytes having the 12-bit
596   starting VLAN ID right justified (the top 4 bits are as specified in
597   <xref target="section-2.1"/> RESV). This is followed by bytes with one bit per VLAN
598   ID. The high order bit of the first byte is for VLAN N. The next-to-the-highest order bit is for VLAN N+1. The low order bit of the first
599   byte is for VLAN N+7.  The high order bit of the second byte, if there
600   is a second byte, is for VLAN N+8, and so on. If that bit is a one,
601   the Address Flush message applies to that VLAN. If that bit is a
602   zero, then addresses that have been learned in that VLAN are not
603   flushed.  Note that Length MUST be at least 2. If Length is 0 or 1,
604   the TLV is corrupt and the Address Flush message MUST be discarded.
605   VLAN IDs do not wrap around. If there are enough bytes so that some
606   bits correspond to VLAN ID 0xFFF or higher, those bits are ignored,
607   but the message is still processed for bits corresponding to valid
608   VLAN IDs.</t>
609
610 </section>
611
612 <section title="Blocks of FGLs" anchor="section-2.2.3"><t>
613   If the TLV Type is 3, the value is a list of blocks of FGLs as
614   follows:</t>
615
616 <figure><artwork><![CDATA[
617   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
618   | Type = 3      | Length        |
619   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
620   | Start.FGL 1                                   |
621   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
622   | End.FGL 1                                     |
623   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
624   | Start.FGL 2                                   |
625   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
626   | End.FGL 2                                     |
627   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
628   | Start.FGL ...                                 |
629   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
630   | End.FGL ...                                   |
631   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
632]]></artwork>
633 </figure>
634 <t>
635   The TLV value consists of sets of Start.FGL and End.FGL numbers. The
636   Address Flush information applies to the FGLs in that range,
637   inclusive. A single FGL is indicated by setting both Start.FGL and
638   End.FGL to the same value. If End.FGL is less than Start.FGL,
639   considering them as unsigned integers, that block is ignored, but the
640   Address Flush message is still processed for any other blocks
641   present. For this Type, Length MUST be a multiple of 6; if it is not,
642   the TLV is corrupt and the Address Flush message MUST be discarded if
643   the receiving RBridge implements Type 3.</t>
644
645 </section>
646
647 <section title="list of FGLs" anchor="section-2.2.4"><t>If the TLV Type is 4, the value is a list of FGLs as follows:</t>
648
649 <figure><artwork><![CDATA[
650   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
651   | Type = 4      | Length        |
652   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
653   | FGL 1                                         |
654   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
655   | FGL 2                                         |
656   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
657   | FGL ...                                       |
658   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
659]]></artwork>
660 </figure>
661 <t>
662   The TLV value consists of FGL numbers each in 3 bytes. The Address
663   Flush message applies to those FGLs. For this Type, Length MUST be a
664   multiple of 3; if it is not, the TLV is corrupt and the Address Flush
665   message MUST be discarded if the receiving RBridge implements Type 4.</t>
666
667 </section>
668
669 <section title="Big Map of FGLs" anchor="section-2.2.5"><t>If the TLV Type is 5, the value is a bit map of FGLs as follows:</t>
670
671
672 <figure><artwork><![CDATA[
673   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
674   | Type = 5      | Length        |
675   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
676   | Start.FGL                                     |
677   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
678   | Bits...
679   +-+-+-+-+-+-+-+-
680]]></artwork>
681 </figure>
682 <t>
683   The TLV value consists of three bytes with the 24-bit starting FGL
684   value N. This is followed by bytes with one bit per FGL. The high
685   order bit of the first byte is for FGL N. The next-to-the-highest
686   order bit is for FGL N+1.  The low order bit of the first byte is for
687   FGL N+7. The high order bit of the second byte, if there is a second
688   byte, is for FGL N+8, and so on. If that bit is a one, the Address
689   Flush message applies to that FGL. If that bit is a zero, then
690   addresses that have been learned in that FGL are not flushed. Note
691   that Length MUST be at least 3. If Length is 0, 1, or 2 for a Type 5
692   TLV, the TLV is corrupt and the Address Flush message MUST be
693   discarded if Type 5 is implemented.  FGLs do not wrap around. If
694   there are enough bytes so that some bits correspond to an FGL higher
695   than 0xFFFFFF, those bits are ignored, but the message is still
696   processed for bits corresponding to valid FGLs.</t>
697
698 </section>
699
700 <section title="All Data Labels" anchor="section-2.2.6"><t>If the TLV Type is 6, the value is null as follows:</t>
701
702 <figure><artwork><![CDATA[
703   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
704   | Type = 6      | Length = 0    |
705   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
706]]></artwork>
707 </figure>
708 <t>
709   This type is used when an RBridge wants to withdraw all addresses for
710   all the Data Labels (all VLANs and FGLs). Length MUST be zero. If
711   Length is any other value, the TLV is corrupt and the Address Flush
712   message MUST be discarded.</t>
713
714 </section>
715
716 <section title="MAC Address List" anchor="section-2.2.7"><t>
717   If the TLV Type is 7, the value is a list of MAC addresses as
718   follows:</t>
719
720 <figure><artwork><![CDATA[
721   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
722   | Type = 7      | Length        |
723   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
724   | MAC 1 upper half                              |
725   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
726   | MAC 1 lower half                              |
727   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
728   | MAC 2 upper half                              |
729   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
730   | MAC 2 lower half                              |
731   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
732   | MAC ... upper half                            |
733   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
734   | MAC ... lower half                            |
735   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
736]]></artwork>
737 </figure>
738 <t>
739   The TLV value consists of a list of 48-bit MAC addresses. Length MUST
740   be a multiple of 6. If it is not, the TLV is corrupt, and the Address
741   Flush message MUST be discarded if the receiving RBridge implements
742   Type 7.</t>
743
744 </section>
745
746 <section title="MAC Address Blocks" anchor="section-2.2.8"><t>
747   If the TLV Type is 8, the value is a list of blocks of MAC addresses
748   as follows:</t>
749
750 <figure><artwork><![CDATA[
751   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
752   | Type = 8      | Length        |
753   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
754   | MAC.start 1 upper half                        |
755   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
756   | MAC.start 1 lower half                        |
757   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
758   | MAC.end 1 upper half                          |
759   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
760   | MAC.end 1 lower half                          |
761   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
762   | MAC.start 2 upper half                        |
763   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
764   | MAC.start 2 lower half                        |
765   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
766   | MAC.end 2 upper half                          |
767   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
768   | MAC.end 2 lower half                          |
769   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
770   | MAC.start ... upper half                      |
771   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
772   | MAC.start ... lower half                      |
773   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
774   | MAC.end ... upper half                        |
775   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
776   | MAC.end ... lower half                        |
777   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
778]]></artwork>
779 </figure>
780 <t>
781   The TLV value consists of sets of Start.MAC and End.MAC numbers. The
782   Address Flush information applies to the 48-bit MAC Addresses in that
783   range, inclusive. A single MAC address is indicated by setting both
784   Start.MAC and End.MAC to the same value. If End.MAC is less than
785   Start.MAC, considering them as unsigned integers, that block is
786   ignored but the Address Flush message is still processed for any
787   other blocks present. For this Type, Length MUST be a multiple of 12;
788   if it is not, the TLV is corrupt and the Address Flush message MUST
789   be discarded if the receiving RBridge implements Type 7.</t>
790
791 </section>
792
793 </section>
794
795 </section>
796
797 <section title="IANA Considerations" anchor="section-3">
798
799 <section title="Address Flush RBridge Channel Protocol Number" anchor="section-3.1"><t>
800   IANA has assigned 0x009 as the Address Flush RBridge Channel
801   Protocol number from the range of RBridge Channel protocols allocated
802   by Standards Action <xref target="RFC7178"/> <xref target="RFC8126"/>.</t>
803
804 <t>
805   The added entry to the "RBridge Channel Protocols" registry at &lt;https://www.iana.org/assignments/trill-parameters/&gt; is as follows:</t>
806
807 <figure><artwork><![CDATA[
808      Protocol  Description       Reference
809      --------  --------------    ------------------
810        0x009    Address Flush     [RFC8383]
811]]></artwork>
812 </figure>
813 </section>
814
815 <section title="TRILL Address Flush TLV Types" anchor="section-3.2"><t>
816   IANA has created the "TRILL Address Flush TLV Types" registry
817   at  &lt;https://www.iana.org/assignments/trill-parameters/&gt; as a subregistry of the "RBridge Channel
818   Protocols" registry.
819   Registry headers are as below. The initial
820   entries are as in the table in <xref target="section-2.2"/>.</t>
821
822<figure><artwork><![CDATA[
823      Registry:  TRILL Address Flush TLV Types
824      Registration Procedures: IETF Review
825      Reference:  [RFC8383]
826]]></artwork>
827 </figure>   
828      
829 
830
831 </section>
832
833 </section>
834
835 <section title="Security Considerations" anchor="section-4"><t>
836   The Address Flush RBridge Channel Protocol itself provides no
837   security assurances or features. However, Address Flush protocol
838   messages can be secured by use of the RBridge Channel Header
839   Extension <xref target="RFC7978"/>. It is RECOMMENDED that all RBridges that
840   implement the Address Flush message be configured to ignore such
841   messages unless they have been secured with an RBridge Channel Header
842   Extension that meets local security policy.</t>
843
844 <t>
845   If RBridges receiving Address Flush messages do not require them to
846   be at least authenticated, they are relatively easy to forge. In that
847   case, such forged Address Flush messages can reduce network
848   efficiency, by purging useful learned information that will have to
849   be relearned. This provides a denial-of-service attack, but cannot
850   cause incorrect operation in the sense that it cannot cause a frame
851   to be improperly delivered.</t>
852
853 <t>
854   See <xref target="RFC7178"/> for general RBridge Channel Security Considerations.</t>
855
856 <t>
857   See <xref target="RFC6325"/> for general TRILL Security Considerations.</t>
858
859 </section>
860      </middle>
861      <back>
862
863
864
865   <references title="Normative References">
866
867   <?rfc include="reference.RFC.2119"?>
868   <?rfc include="reference.RFC.6325"?>
869   <?rfc include="reference.RFC.7172"?>
870   <?rfc include="reference.RFC.7178"?>
871   <?rfc include="reference.RFC.7780"?>
872   <?rfc include="reference.RFC.7978"?>
873   <?rfc include="reference.RFC.8174"?>
874
875
876 </references>
877
878 <references title="Informative References">
879
880   <?rfc include="reference.RFC.4762"?>
881    <?rfc include="reference.RFC.8126"?>
882   
883 </references>
884
885
886 <section title="Acknowledgements" numbered="no" anchor="acknowledgements"><t><list style="hanging" hangIndent="3"><t hangText="The following are thanked for their contributions:">
887 <vspace blankLines="1"/>
888 Ramkumar Parameswaran, Henning Rogge
889 </t>
890
891 </list>
892      </t>
893
894 </section>
895
896 </back>
897
898 </rfc>
899