rfc8856xml2.original.xml   rfc8856.xml 
<?xml version="1.0" encoding="UTF-8"?> <?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE rfc SYSTEM "rfc2629-xhtml.ent">
<!DOCTYPE rfc SYSTEM "rfc2629.dtd">
<?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?>
<rfc category="std" ipr="trust200902" docName="draft-ietf-bfcpbis-rfc4583bis-27"
obsoletes="4583">
<?rfc strict="yes"?>
<?rfc toc="yes"?>
<?rfc tocdepth="4"?>
<?rfc symrefs="no"?>
<?rfc sortrefs="yes" ?>
<?rfc compact="yes" ?>
<?rfc subcompact="no" ?>
<?rfc symrefs="yes" ?>
<front>
<title abbrev="BFCP">Session Description Protocol (SDP) Format for Binary Floo
r Control Protocol (BFCP) Streams</title>
<author initials="G." surname="Camarillo" fullname="Gonzalo Camarillo">
<organization>Ericsson</organization>
<address>
<postal>
<street>Hirsalantie 11</street>
<city>FI-02420 Jorvas</city>
<country>Finland</country>
</postal>
<email>Gonzalo.Camarillo@ericsson.com</email>
</address>
</author>
<author fullname="Tom Kristensen" initials="T." surname="Kristensen">
<organization>Cisco</organization>
<address>
<postal>
<street>Philip Pedersens vei 1</street>
<city>NO-1366 Lysaker</city>
<country>Norway</country>
</postal>
<email>tomkrist@cisco.com, tomkri@ifi.uio.no</email>
</address>
</author>
<author initials="C.H." surname="Holmberg" fullname="Christer Holmberg"> <rfc xmlns:xi="http://www.w3.org/2001/XInclude" category="std"
<organization>Ericsson</organization> ipr="trust200902" docName="draft-ietf-bfcpbis-rfc4583bis-27"
<address> number="8856" obsoletes="4583" updates="" submissionType="IETF"
<postal> consensus="true" xml:lang="en" tocInclude="true" tocDepth="4" symRefs="true
<street>Hirsalantie 11</street> " sortRefs="true" version="3">
<!-- xml2rfc v2v3 conversion 2.37.3 -->
<front>
<title abbrev="SDP Format for BFCP Streams">Session Description Protocol (SD
P) Format for Binary
Floor Control Protocol (BFCP) Streams</title>
<seriesInfo name="RFC" value="8856"/>
<author initials="G." surname="Camarillo" fullname="Gonzalo Camarillo">
<organization>Ericsson</organization>
<address>
<postal>
<street>Hirsalantie 11</street>
<code>02420</code> <code>02420</code>
<city>Jorvas</city> <city>Jorvas</city>
<country>Finland</country> <country>Finland</country>
</postal> </postal>
<email>christer.holmberg@ericsson.com</email> <email>Gonzalo.Camarillo@ericsson.com</email>
</address> </address>
</author> </author>
<author fullname="Tom Kristensen" initials="T." surname="Kristensen">
<date year="2018"/> <organization abbrev="Jotron">Jotron AS</organization>
<address>
<area>Real-time Applications and Infrastructure</area> <postal>
<workgroup>BFCPbis Working Group</workgroup> <street>Ringdalskogen 8</street>
<code>3270</code>
<city>Larvik</city>
<country>Norway</country>
</postal>
<email>tom.kristensen@jotron.com, tomkri@ifi.uio.no</email>
</address>
</author>
<author initials="C." surname="Holmberg" fullname="Christer Holmberg">
<organization>Ericsson</organization>
<address>
<postal>
<street>Hirsalantie 11</street>
<code>02420</code>
<city>Jorvas</city>
<country>Finland</country>
</postal>
<email>christer.holmberg@ericsson.com</email>
</address>
</author>
<date month="May" year="2020"/>
<keyword>floor control</keyword> <keyword>floor control</keyword>
<keyword>BFCP</keyword> <keyword>BFCP</keyword>
<keyword>SDP</keyword> <keyword>SDP</keyword>
<abstract> <abstract>
<t>This document defines the Session Description Protocol (SDP) offer/answer <t>This document defines the Session Description Protocol (SDP)
procedures for negotiating and establishing Binary Floor Control Protocol (BFCP) offer/answer procedures for negotiating and establishing Binary Floor
streams.</t> Control Protocol (BFCP) streams.</t>
<t>This document obsoletes RFC 4583. Changes from RFC 4583 are summarized in
Section 14.</t>
<!-- Ensure correct section #, as xref is no
t allowed in abstract -->
</abstract>
</front>
<middle> <t>This document obsoletes RFC 4583.</t>
<section title="Introduction"> </abstract>
<t>As discussed in the BFCP (Binary Floor Control Protocol) specification <x </front>
ref target="I-D.ietf-bfcpbis-rfc4582bis"/>, a <middle>
<section numbered="true" toc="default">
<name>Introduction</name>
<t>As discussed in the BFCP (Binary Floor Control Protocol) specification
<xref target="RFC8855" format="default"/>, a
given BFCP client needs a set of data in order to establish a BFCP connectio n to a floor control server. This data includes given BFCP client needs a set of data in order to establish a BFCP connectio n to a floor control server. This data includes
the transport address of the server, the conference identifier, and the user identifier.</t> the transport address of the server, the conference identifier, and the user identifier.</t>
<t>One way for clients to obtain this information is to use an SDP offer/ans <t>One way for clients to obtain this information is to use a Session
wer <xref target="RFC3264"/> exchange. Description Protocol (SDP) offer/answer exchange <xref target="RFC3264" fo
rmat="default"/>.
This document specifies how to encode this information in the SDP session de scriptions that are part of such an offer/answer This document specifies how to encode this information in the SDP session de scriptions that are part of such an offer/answer
exchange.</t> exchange.</t>
<t>User agents typically use the offer/answer model to establish a number of <t>User agents typically use the offer/answer model to establish a number
media streams of different types. of media streams of different types.
Following this model, a BFCP connection is described as any other media stre Following this model, a BFCP connection is described as any other media stre
am by using an SDP 'm' line, possibly am by using an SDP "m=" line, possibly
followed by a number of SDP lines that also apply to the BFCP connection.</t > followed by a number of SDP lines that also apply to the BFCP connection.</t >
<t><xref target="sec:m-line"/> defines how the field values in 'm' line repr <t><xref target="sec_m-line" format="default"/> defines how the field
esenting a BFCP connection are set.</t> values in an "m=" line representing a BFCP connection are set.</t>
<t><xref target="sec:attributes"/> defines SDP attributes that are used when <t><xref target="sec_attributes" format="default"/> defines SDP attributes
negotiating a BFCP connection.</t> that are used when negotiating a BFCP connection.</t>
<t><xref target="sec:mux-cons"/> defines multiplexing considerations for a B <t><xref target="sec_mux-cons" format="default"/> defines multiplexing con
FCP connection.</t> siderations for a BFCP connection.</t>
<t><xref target="sec:bfcp-connection"/> defines procedures for managing a BF <t><xref target="sec_bfcp-connection" format="default"/> defines procedure
CP connection.</t> s for managing a BFCP connection.</t>
<t><xref target="sec:authentication"/> defines TLS and DTLS considerations w <t><xref target="sec_authentication" format="default"/> defines TLS and DT
hen negotiating a BFCP connection.</t> LS considerations when negotiating a BFCP connection.</t>
<t><xref target="sec:ice-considerations"/> defines the Interactive Connectiv <t><xref target="sec_ice-considerations" format="default"/> defines
ity Establishment (ICE) considerations regarding Interactive Connectivity Establishment (ICE)
<xref target="RFC8445"/> considerations when negotiating a BFCP connection.< <xref target="RFC8445" format="default"/> when negotiating a BFCP connection
/t> .</t>
<t><xref target="sec:oa-offer-answer-proc"/> defines the SDP offer/answer pr <t><xref target="sec_oa-offer-answer-proc" format="default"/> defines
ocedures for negotiating a BFCP connection.</t> the SDP offer/answer procedures for negotiating a BFCP connection.</t>
</section>
<section title="Conventions">
<t>
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOUL
D", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED",
"MAY", and "OPTIONAL" in this document are to be interpreted as described
in BCP 14 <xref target="RFC2119"></xref> <xref target="RFC8174"></xref>
when, and only when, they appear in all capitals, as shown here.
</t>
</section>
<section title="Floor Control Roles" anchor="sec:server-determination"> <t>This document obsoletes RFC 4583 <xref target="RFC4583"/>. <xref
<t> target="sec_changes"/> summarizes the changes
from RFC 4583.</t>
</section>
<section numbered="true" toc="default">
<name>Conventions</name>
<t>The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>",
"<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>",
"<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>",
"<bcp14>SHOULD NOT</bcp14>",
"<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
"<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are
to be interpreted as described in BCP&nbsp;14 <xref target="RFC2119"/>
<xref target="RFC8174"/> when, and only when, they appear in all capitals,
as shown here.</t>
</section>
<section anchor="sec_server-determination" numbered="true" toc="default">
<name>Floor Control Roles</name>
<t>
When two endpoints establish a BFCP stream, they need to determine which of them acts as a floor control client and which acts as a floor control server. When two endpoints establish a BFCP stream, they need to determine which of them acts as a floor control client and which acts as a floor control server.
</t> </t>
<t>
Once the roles have been determined, the roles will apply to all BFCP-con
trolled streams associated with the BFCP stream.
</t>
</section>
<section title="Fields in the 'm' Line" anchor="sec:m-line">
<t>According to the SDP specification <xref target="RFC4566"/>, the 'm' line
format is the following:</t>
<t><list style="hanging">
<t><![CDATA[m=<media> <port> <proto> <fmt> ...]]></t>
</list></t>
<t>This section describes how to generate an 'm' line of an SDP Media Descri
ption ('m' section) describing a BFCP stream.</t>
<t>The media field MUST have a value of "application".</t>
<t>The port field is set depending on the value of the proto field, as expla
ined below. A port field value of zero has the standard SDP meaning (i.e., reje
ction of the media stream) regardless of the proto field.</t>
<t><list style="hanging">
<t>When TCP is used as the transport, the port field is set following th
e rules in <xref target="RFC4145"/>. Depending on the value of the 'setup' attri
bute (discussed in <xref target="sec:tcp-connection"/>), the port field contains
the port to which the remote endpoint will direct BFCP messages, or in the case
where the endpoint will initiate the connection towards the remote endpoint, sh
ould be set to a value of 9.</t>
<t>When UDP is used as the transport, the port field contains the port t
o which the remote endpoint will direct BFCP messages regardless of the value of
the 'setup' attribute.</t>
</list></t>
<t>This document defines five values for the proto field: TCP/BFCP, TCP/DTLS
/BFCP, TCP/TLS/BFCP, UDP/BFCP, and UDP/TLS/BFCP.</t>
<t>The proto value are used as described below:</t>
<t><list style="hanging">
<t>'TCP/BFCP' is used for TCP transport of BFCP without TLS encryption, an
d is backward compatible with RFC 4583 compliant endpoints.</t>
<t>'TCP/TLS/BFCP' is used for TCP transport of BFCP with TLS encryption, a
nd is backward compatible with RFC 4583 compliant endpoints that support TLS.</t
>
<t>'UDP/BFCP' is used for UDP transport of BFCP without DTLS encryption <x
ref target="RFC6347"/>.</t>
<t>'UDP/TLS/BFCP' is used for UDP transport of BFCP with DTLS encryption.
This is one of the options when ICE is used (<xref target="sec:ice-consideration
s"/>). It can also be used without ICE
when backward compatibility with RFC 4583 compliant endpoints is not r
equired.</t>
<t>'TCP/DTLS/BFCP' is used for TCP transport of BFCP with DTLS encryption,
running on top of TCP using the framing method defined in <xref target="RFC4571
"/>, with DTLS packets being
sent and received instead of RTP/RTCP packets using the shim defined i
n RFC 4571 such that the length field defined in RFC 4571 precedes each DTLS mes
sage. This is one of the options when
ICE is used (<xref target="sec:ice-considerations"/>). It can also be
used without ICE when backward compatibility with RFC 4583 compliant endpoints i
s not required.</t>
</list></t>
<t>The fmt (format) list is not applicable to BFCP. The fmt list of 'm' line
s in the case of any proto field value related to BFCP MUST contain a single "*"
character. If the the fmt list contains any other value it MUST be ignored.</t>
<t>The following is an example of an 'm' line for a BFCP connection:</t>
<figure>
<artwork>
m=application 50000 TCP/TLS/BFCP *
</artwork>
</figure>
</section>
<section title="SDP Attributes" anchor="sec:attributes">
<section title="SDP 'floorctrl' Attribute" anchor="sec:floorctrl-attr">
<t> <t>
Once the roles have been determined, the roles will apply to all BFCP-con
trolled streams associated with the BFCP stream.
</t>
</section>
<section anchor="sec_m-line" numbered="true" toc="default">
<name>Fields in the "m=" Line</name>
<t>According to the SDP specification <xref target="RFC4566" format="defau
lt"/>, the "m=" line format is as follows:</t>
<sourcecode name="" type="sdp"><![CDATA[
m=<media> <port> <proto> <fmt> ... ]]></sourcecode>
<t>This section describes how to generate an "m=" line of an SDP Media Des
cription ("m=" section) describing a BFCP stream.</t>
<t>The media field <bcp14>MUST</bcp14> have a value of "application".</t>
<t>Depending on the value of the proto field, the port field is set as exp
lained below. A port field value of zero has the standard SDP meaning (i.e., re
jection of the media stream), regardless of the proto field.</t>
<ul spacing="normal">
<li>When TCP is used as the transport, the port field is set following
the rules in <xref target="RFC4145" format="default"/>. Depending on
the value of the 'setup' attribute (defined in <xref
target="RFC4145"/> and discussed in <xref target="sec_tcp-connection" for
mat="default"/>), the port field contains the port to which the remote endpoint
will direct BFCP messages, or in the case where the endpoint will initiate the c
onnection towards the remote endpoint, should be set to a value of 9.</li>
<li>When UDP is used as the transport, the port field contains the port
to which the remote endpoint will direct BFCP messages, regardless of the value
of the 'setup' attribute.</li>
</ul>
<t>This document defines five values for the proto field: 'TCP/BFCP', 'TCP
/DTLS/BFCP', 'TCP/TLS/BFCP', 'UDP/BFCP', and 'UDP/TLS/BFCP'.</t>
<t>The proto values are used as described below:</t>
<ul spacing="normal">
<li>'TCP/BFCP' is used for TCP transport of BFCP without TLS
encryption and is backward compatible with endpoints that are compliant w
ith RFC 4583.</li>
<li>'TCP/TLS/BFCP' is used for TCP transport of BFCP with TLS
encryption and is backward compatible with endpoints that are
compliant with RFC 4583 and support TLS.</li>
<li>'UDP/BFCP' is used for UDP transport of BFCP without DTLS encryption
<xref target="RFC6347" format="default"/>.</li>
<li>'UDP/TLS/BFCP' is used for UDP transport of BFCP with DTLS
encryption. This is one of the options when ICE is used (<xref target="se
c_ice-considerations" format="default"/>). It can also be used without ICE
when backward compatibility with endpoints compliant with RFC 4583 is
not required.</li>
<li>'TCP/DTLS/BFCP' is used for TCP transport of BFCP with DTLS encrypti
on, running on top of TCP using the framing method defined in <xref target="RFC4
571" format="default"/>, with DTLS packets being
sent and received instead of RTP / RTP Control Protocol (RTCP)
packets, such that the LENGTH field defined in RFC 4571 precedes
each DTLS message. This is one of the options when
ICE is used (<xref target="sec_ice-considerations"
format="default"/>). It can also be used without ICE when backward
compatibility with endpoints compliant with RFC 4583 is not required.</li
>
</ul>
<t>The fmt (format) list is not applicable to BFCP. The fmt list of "m=" l
ines in the case of any proto field value related to BFCP <bcp14>MUST</bcp14> co
ntain a single "*" character. If the fmt list contains any other value, it <bcp1
4>MUST</bcp14> be ignored.</t>
<t>The following is an example of an "m=" line for a BFCP connection:</t>
<sourcecode name="" type="sdp"><![CDATA[
m=application 50000 TCP/TLS/BFCP * ]]></sourcecode>
</section>
<section anchor="sec_attributes" numbered="true" toc="default">
<name>SDP Attributes</name>
<section anchor="sec_floorctrl-attr" numbered="true" toc="default">
<name>SDP 'floorctrl' Attribute</name>
<t>
This section defines the SDP 'floorctrl' media-level attribute. The att ribute is used to determine the floor control roles (client and server) for the endpoints associated with This section defines the SDP 'floorctrl' media-level attribute. The att ribute is used to determine the floor control roles (client and server) for the endpoints associated with
the BFCP stream. the BFCP stream.
</t> </t>
<figure>
<artwork type='abnf'>
Attribute Name: floorctrl
Attribute Value: floor-control
Usage Level: media
Charset Dependent: No
Mux Category: TBD <ul empty="true"><li>
<dl>
<dt>Attribute Name:</dt><dd>floorctrl</dd>
<dt>Attribute Value:</dt><dd>floor-control</dd>
<dt>Usage Level:</dt><dd>media</dd>
<dt>Charset Dependent:</dt><dd>No</dd>
<dt>Mux Category:</dt><dd>TBD</dd>
</dl>
</li></ul>
The Augmented BNF syntax [RFC5234] for the attribute is: <t>The Augmented BNF syntax <xref target="RFC5234"/> for the attribute is:</
t>
<sourcecode name="" type="abnf"><![CDATA[
floor-control = role *(SP role)
role = "c-only" / "s-only" / "c-s" ]]></sourcecode>
floor-control = role *(SP role) <t>An endpoint includes the attribute to indicate the role(s) it would be w
role = "c-only" / "s-only" / "c-s" illing to perform for the BFCP-controlled media streams:</t>
</artwork> <ul empty="true"><li>
</figure> <dl newline="false" spacing="normal">
<t>An endpoint includes the attribute to indicate the role(s) it would be <dt>c-only:</dt>
willing to perform for the BFCP-controlled media streams:</t> <dd>The endpoint is willing to act as a floor control client.</dd>
<t><list style="hanging"> <dt>s-only:</dt>
<t hangText="c-only:">The endpoint is willing to act as floor control <dd>The endpoint is willing to act as a floor control server only.</dd
client.</t> >
<t hangText="s-only:">The endpoint is willing to act as floor control </dl></li></ul>
server only.</t> <t>
</list></t> When inserted in an offer, the offerer <bcp14>MAY</bcp14> indicate multi
<t> ple attribute values ("c-only" and "s-only"). When inserted in an answer, the an
When inserted in an offer, the offerer MAY indicate multiple attribute v swerer <bcp14>MUST</bcp14>
alues ("c-only" and "s-only"). When inserted in an answer, the answerer MUST
indicate only one attribute value: "c-only" or "s-only". The answerer in dicates the role taken by the answerer. The offerer will then take the indicate only one attribute value: "c-only" or "s-only". The answerer in dicates the role taken by the answerer. The offerer will then take the
opposite role. opposite role.
</t> </t>
<t> <t>
In <xref target="RFC4583"/>, there was a third attribute specified, "c-s In <xref target="RFC4583" format="default"/>, there was a third
", which meant that an endpoint was willing to act as both floor control client attribute specified, "c-s", which meant that an endpoint was willing
and to act as both a floor control client and a
floor control server at the same time for the BFCP stream, taking differ ent roles for different BFCP-controlled media streams. The feature was underspec ified floor control server at the same time for the BFCP stream, taking differ ent roles for different BFCP-controlled media streams. The feature was underspec ified
and implemented in different ways, in particular many implementations in and implemented in different ways; in particular, many implementations
terpreted "c-s” to mean that the endpoint is willing to act as either client or interpreted "c-s" to mean that the endpoint is willing to act as
server either a client or a server
(equivalent to “c-only s-only”). An implementation compliant to this spe (equivalent to "c-only s-only"). An implementation compliant with this s
cification MUST NOT include the "c-s" floorctl attribute value in an offer or in pecification <bcp14>MUST NOT</bcp14> include the "c-s" 'floorctrl' attribute val
an answer, ue in an offer or in an answer
but MUST accept the attribute value in an offer and process it as equiva but <bcp14>MUST</bcp14> accept the attribute value in an offer and
lent to "c-only s-only" (or "s-only c-only"). Also, as an implementation complia process it as equivalent to "c-only s-only" (or "s-only c-only"). Also, a
nt to s an implementation compliant with
this specification is only allowed to include one role, either 'c-only' this specification is only allowed to include one role -- either
or 's-conly', in an answer, each endpoint will only take one role, and as a resu "c-only" or "s-only" -- in an answer, each endpoint will only take one ro
lt le, and as a result
the endpoint will take the same role for each BFCP-controlled media stre am associated with the BFCP stream. the endpoint will take the same role for each BFCP-controlled media stre am associated with the BFCP stream.
</t> </t>
<t> <t>
<xref target="tab-roles"/> shows the roles that the answerer is allowed <xref target="tab-roles" format="default"/> shows the roles that the ans
to take, based on what roles the offerer has werer is allowed to take, based on what roles the offerer has
indicated that it is willing to take. indicated that it is willing to take.
</t> </t>
<texttable title="Roles" anchor="tab-roles"> <table anchor="tab-roles" align="center">
<ttcol align="center">Offerer</ttcol> <name>Roles</name>
<ttcol align="center">Answerer</ttcol> <thead>
<tr>
<c>c-only</c> <th align="center">Offerer</th>
<c>s-only</c> <th align="center">Answerer</th>
</tr>
<c>s-only</c> </thead>
<c>c-only</c> <tbody>
<tr>
<td align="center">c-only</td>
<td align="center">s-only</td>
</tr>
<tr>
<td align="center">s-only</td>
<td align="center">c-only</td>
</tr>
<tr>
<td align="center">c-s</td>
<td align="center">c-only</td>
</tr>
<tr>
<td align="center">c-s</td>
<td align="center">s-only</td>
</tr>
</tbody>
</table>
<t>
Endpoints compliant with <xref target="RFC4583" format="default"/> might
not include the 'floorctrl' attribute in offers and answers.
If the 'floorctrl' attribute is not present, in order to be
interoperable with such endpoints, the offerer will act as a floor contro
l client
and the answerer will act as a floor control server.
</t>
<t>
The SDP Offer/Answer procedures for the 'floorctrl' attribute are define
d in <xref target="sec_oa-offer-answer-proc" format="default"/>.
</t>
<t>The following is an example of a 'floorctrl' attribute in an offer:</
t>
<c>c-s</c> <sourcecode name="" type="sdp"><![CDATA[
<c>c-only</c> a=floorctrl:c-only s-only ]]></sourcecode>
<c>c-s</c> </section>
<c>s-only</c> <section anchor="sec_confid-attr" numbered="true" toc="default">
</texttable> <name>SDP 'confid' Attribute</name>
<t>
Endpoints compliant with <xref target="RFC4583"/> might not include the
'floorctrl' attribute in offers and answerer.
If the 'floorctrl' attribute is not present, in order to be interoperabl
e with such endpoints, the offerer will act as floor control client
and the answerer will act as floor control server.
</t>
<t>
The SDP Offer/Answer procedures for the 'floorctrl' attribute are define
d in <xref target="sec:oa-offer-answer-proc"/>.
</t>
<t>The following is an example of a 'floorctrl' attribute in an offer:</t>
<figure>
<artwork>
a=floorctrl:c-only s-only
</artwork>
</figure>
</section>
<section title="SDP 'confid' Attribute" anchor="sec:confid-attr"> <t>
<t>
This section defines the SDP 'confid' media-level attribute. The attribute is used by a floor control server This section defines the SDP 'confid' media-level attribute. The attribute is used by a floor control server
to convey the conference ID value to the floor control client, using decim al integer representation. to convey the conference ID value to the floor control client, using decim al integer representation.
</t> </t>
<figure>
<artwork type='abnf'><![CDATA[
Attribute Name: confid
Attribute Value: conference-id
Usage Level: media
Charset Dependent: No
Mux Category: TBD
The Augmented BNF syntax [RFC5234] for the attribute is:
conference-id = 1*DIGIT <ul empty="true"><li>
<dl>
<dt>Attribute Name:</dt><dd>confid</dd>
<dt>Attribute Value:</dt><dd>conference-id</dd>
<dt>Usage Level:</dt><dd>media</dd>
<dt>Charset Dependent:</dt><dd>No</dd>
<dt>Mux Category:</dt><dd>NORMAL</dd>
</dl>
</li></ul>
DIGIT = <DIGIT defined in [RFC5234]> <t>The Augmented BNF syntax <xref target="RFC5234"/> for the attribute is:</
t>
<sourcecode name="" type="abnf"><![CDATA[
conference-id = 1*DIGIT
The maximum value of the attribute is determined by the DIGIT = <DIGIT as defined in [RFC5234]> ]]></sourcecode>
COMMON-HEADER format [I-D.ietf-bfcpbis-rfc4582bis].
]]></artwork> <t>The maximum value of the attribute is determined by the
</figure> COMMON-HEADER format <xref target="RFC8855"/>.</t>
<t>
The SDP Offer/Answer procedures for the 'confid' attribute are defined in
<xref target="sec:oa-offer-answer-proc"/>.
</t>
</section>
<section title="SDP 'userid' Attribute" anchor="sec:userid-attr"> <t>
<t> The SDP Offer/Answer procedures for the 'confid' attribute are defined in
This section defines the SDP userid' media-level attribute. The attribute <xref target="sec_oa-offer-answer-proc" format="default"/>.
is used by a floor control server </t>
</section>
<section anchor="sec_userid-attr" numbered="true" toc="default">
<name>SDP 'userid' Attribute</name>
<t>
This section defines the SDP 'userid' media-level attribute. The attribute
is used by a floor control server
to convey the user ID value to the floor control client, using decimal int eger representation. to convey the user ID value to the floor control client, using decimal int eger representation.
</t> </t>
<figure>
<artwork type='abnf'><![CDATA[
Attribute Name: userid
Attribute Value: user-id
Usage Level: media
Charset Dependent: No
Mux Category: TBD
The Augmented BNF syntax [RFC5234] for the attribute is:
user-id = 1*DIGIT
DIGIT = <DIGIT defined in [RFC5234]>
The maximum value of the attribute is determined by the
COMMON-HEADER format [I-D.ietf-bfcpbis-rfc4582bis].
]]></artwork>
</figure>
<t>
The SDP Offer/Answer procedures for the 'userid' attribute are defined in
<xref target="sec:oa-offer-answer-proc"/>.
</t>
</section>
<section title="SDP 'floorid' Attribute" anchor="sec:floorid-attr">
<t>
This section defines the SDP 'floorid' media-level attribute. The attribut
e conveys a floor identifier, using decimal integer
representation, and optionally pointers to one or more BFCP-controlled med
ia streams.
</t>
<figure>
<artwork type='abnf'><![CDATA[
Attribute Name: floorid
Attribute Value: floor-id
Usage Level: media
Charset Dependent: No
Mux Category: TBD
The Augmented BNF syntax [RFC5234] for the attribute is: <ul empty="true"><li>
<dl>
<dt>Attribute Name:</dt><dd>userid</dd>
<dt>Attribute Value:</dt><dd>user-id</dd>
<dt>Usage Level:</dt><dd>media</dd>
<dt>Charset Dependent:</dt><dd>No</dd>
<dt>Mux Category:</dt><dd>NORMAL</dd>
</dl>
</li></ul>
floor-id = 1*DIGIT SP "mstrm:" token *(SP token) <t>The Augmented BNF syntax <xref target="RFC5234"/> for the attribute is:</
t>
<sourcecode name="" type="abnf"><![CDATA[
user-id = 1*DIGIT
DIGIT = <DIGIT defined in [RFC5234]> DIGIT = <DIGIT as defined in [RFC5234]> ]]></sourcecode>
token = <token defined in [RFC4566]>
The maximum value of the attribute is determined by the <t>The maximum value of the attribute is determined by the
FLOOR-ID format [I-D.ietf-bfcpbis-rfc4582bis]. COMMON-HEADER format <xref target="RFC8855"/>.</t>
]]></artwork> <t>
</figure> The SDP Offer/Answer procedures for the 'userid' attribute are defined in
<t> <xref target="sec_oa-offer-answer-proc" format="default"/>.
The floor identifier value is the integer representation of the Floor ID t </t>
o be used in BFCP. Each media stream </section>
pointer value is associated with an SDP 'label' attribute <xref target="RF <section anchor="sec_floorid-attr" numbered="true" toc="default">
C4574"/> of a media stream. <name>SDP 'floorid' Attribute</name>
</t> <t>
<t> This section defines the SDP 'floorid' media-level attribute. The
The SDP Offer/Answer procedures for the 'floorid' attribute are defined in attribute is used to convey a floor identifier, using decimal integer
<xref target="sec:oa-offer-answer-proc"/>. representation, and, optionally, pointers to one or more BFCP-controlled
</t> media streams.</t>
<t><list style="empty">
<t>
Note: In <xref target="RFC4583"/> 'm-stream' was erroneously used in <xref
target="sec:example"/>. Although the example was non-normative, it is
implemented by some vendors and occurs in cases where the endpoint is will
ing to act as a server. Therefore, it is RECOMMENDED to support parsing and
interpreting 'm-stream' the same way as 'mstrm' when receiving.
</t>
</list></t>
</section>
<section title="SDP 'bfcpver' Attribute" anchor="sec:bfcp-version-attr"> <ul empty="true"><li>
<t> <dl>
This section defines the SDP 'bfcpver' media-level attribute. The attribut <dt>Attribute Name:</dt><dd>floorid</dd>
e is used to negotiate the <dt>Attribute Value:</dt><dd>floor-id</dd>
BFCP version, using decimal integer representation. <dt>Usage Level:</dt><dd>media</dd>
</t> <dt>Charset Dependent:</dt><dd>No</dd>
<t> <dt>Mux Category:</dt><dd>NORMAL</dd>
The Augmented BNF syntax <xref target="RFC5234"/> for the attributes is: </dl>
</t> </li></ul>
<figure>
<artwork type='abnf'><![CDATA[
Attribute Name: bfcpver
Attribute Value: bfcp-version <t>The Augmented BNF syntax <xref target="RFC5234"/> for the attribute is:</
t>
<sourcecode name="" type="abnf"><![CDATA[
floor-id = 1*DIGIT SP "mstrm:" token *(SP token)
Usage Level: media DIGIT = <DIGIT as defined in [RFC5234]>
token = <token as defined in [RFC4566]> ]]></sourcecode>
Charset Dependent: No <t>The maximum value of the attribute is determined by the
FLOOR-ID format <xref target="RFC8855"/>.</t>
Mux Category: TBD <t>The floor identifier value is the integer representation of the
Floor&nbsp;ID field value <xref target="RFC8855"/> to be used in BFCP. E
ach media stream
pointer value is associated with an SDP 'label' attribute <xref target="RF
C4574" format="default"/> of a media stream.
</t>
<t>
The SDP Offer/Answer procedures for the 'floorid' attribute are defined in
<xref target="sec_oa-offer-answer-proc" format="default"/>.
</t>
<aside><t>Note: In the first SDP example in
<xref target="RFC4583" sectionFormat="of" section="9"/>, 'm-stream'
was erroneously listed. Although the example was non&nbhy;normative, it is
implemented by some vendors and occurs in cases where the endpoint is will
ing to act as a server. Therefore, it is <bcp14>RECOMMENDED</bcp14> to support p
arsing and
interpreting 'm-stream' the same way as 'mstrm' when receiving.</t></aside
>
</section>
<section anchor="sec_bfcp-version-attr" numbered="true" toc="default">
<name>SDP 'bfcpver' Attribute</name>
<t>
This section defines the SDP 'bfcpver' media-level attribute. The
attribute is used to negotiate the BFCP version, using decimal integer
representation.
</t>
The Augmented BNF syntax [RFC5234] for the attribute is: <ul empty="true"><li>
<dl>
<dt>Attribute Name:</dt><dd>bfcpver</dd>
<dt>Attribute Value:</dt><dd>bfcp-version</dd>
<dt>Usage Level:</dt><dd>media</dd>
<dt>Charset Dependent:</dt><dd>No</dd>
<dt>Mux Category:</dt><dd>TBD</dd>
</dl>
</li></ul>
bfcp-version = version *(SP version) <t>The Augmented BNF syntax <xref target="RFC5234"/> for the attribute is:</
version = 1*DIGIT t>
<sourcecode name="" type="abnf"><![CDATA[
bfcp-version = version *(SP version)
version = 1*DIGIT
DIGIT = <DIGIT defined in [RFC5234]> DIGIT = <DIGIT as defined in [RFC5234]> ]]></sourcecode>
The maximum value of the attribute is determined by the <t>The maximum value of the attribute is determined by the
COMMON-HEADER format [I-D.ietf-bfcpbis-rfc4582bis]. COMMON-HEADER format <xref target="RFC8855"/>.</t>
]]></artwork> <t>
</figure>
<t>
An endpoint uses the 'bfcpver' attribute to convey the version(s) of BFCP supported by the endpoint, using integer values. For a given version, the attrib ute An endpoint uses the 'bfcpver' attribute to convey the version(s) of BFCP supported by the endpoint, using integer values. For a given version, the attrib ute
value representing the version MUST match the "Version" field that would b e presented in the BFCP COMMON-HEADER <xref target="I-D.ietf-bfcpbis-rfc4582bis" />. value representing the version <bcp14>MUST</bcp14> match the version ("Ver ") field that would be presented in the BFCP COMMON&nbhy;HEADER <xref target="RF C8855" format="default"/>.
The BFCP version that will eventually be used will be conveyed with a BFCP -level Hello/HelloAck. The BFCP version that will eventually be used will be conveyed with a BFCP -level Hello/HelloAck.
</t> </t>
<t> <t>
Endpoints compliant with <xref target="RFC4583"/> might not always include Endpoints compliant with <xref target="RFC4583" format="default"/> might n
the 'bfcpver' ot always include the 'bfcpver'
attribute in offers and answers. The attribute value, if present, MUST be attribute in offers and answers. The attribute value, if present, <bcp14>M
in accordance with UST</bcp14> be in accordance with
the definition of the Version field in <xref target="I-D.ietf-bfcpbis-rfc4 the definition of the version ("Ver") field in <xref target="RFC8855" form
582bis"/>. If the at="default"/>. If the
attribute is not present, endpoints MUST assume a default value in accorda attribute is not present, endpoints <bcp14>MUST</bcp14> assume a default v
nce with alue in accordance with
<xref target="I-D.ietf-bfcpbis-rfc4582bis"/>: when used over a reliable tr <xref target="RFC8855" format="default"/>: when used over a reliable trans
ansport the default port, the default
attribute value is "1", and when used over an unreliable transport the def attribute value is "1", and when used over an unreliable transport, the de
ault attribute value fault attribute value
is "2". The value is inferred from the transport specified in the 'm' line is "2". The value is inferred from the transport specified in the "m=" lin
(<xref target="sec:m-line"/>) e (<xref target="sec_m-line" format="default"/>)
of the 'm' section associated with the stream. of the "m=" section associated with the stream.
</t> </t>
<t> <t>
The SDP Offer/Answer procedures for the 'bfcpver' attribute are defined in The SDP Offer/Answer procedures for the 'bfcpver' attribute are defined in
<xref target="sec:oa-offer-answer-proc"/>. <xref target="sec_oa-offer-answer-proc" format="default"/>.
</t> </t>
</section> </section>
</section> </section>
<section title="Multiplexing Considerations" anchor="sec:mux-cons"> <section anchor="sec_mux-cons" numbered="true" toc="default">
<t> <name>Multiplexing Considerations</name>
<xref target="I-D.ietf-mmusic-sdp-bundle-negotiation"/> defines how multip
lexing of multiple media streams can be negotiated. This specification does not
define
how BFCP streams can be multiplexed with other media streams. Therefore, a
BFCP stream MUST NOT be associated with a BUNDLE group <xref target="I-D.ietf-m
music-sdp-bundle-negotiation"/>.
Note that BFCP-controlled media streams might be multiplexed with other me
dia streams.
</t>
<t>
<xref target="I-D.ietf-mmusic-sdp-mux-attributes"/> defines the mux catego
ries for the SDP
attributes defined in this specification, except for the 'bfcpver' attribu
te. <xref target="tab:mux-tbd"/> defines the mux category
for the 'bfcpver' attribute:
</t>
<texttable title="Multiplexing Attribute Analysis" anchor="tab:mux-tbd">
<ttcol>Name</ttcol>
<ttcol>Notes</ttcol>
<ttcol>Level</ttcol>
<ttcol>Mux Category</ttcol>
<c>bfcpver</c>
<c>Needs further analysis in a separate specification</c>
<c>M</c>
<c>TBD</c>
</texttable>
</section>
<section title="BFCP Connection Management" anchor="sec:bfcp-connection">
<t>
BFCP streams can use TCP or UDP as the underlying transport. Endpoints exc
hanging BFCP messages over UDP send the BFCP messages towards the peer
using the connection address and port provided in the SDP 'c' and 'm' line
s. TCP connection management is more complicated and is described in
the following Section.
</t>
<t><list style="empty">
<t>Note: When using Interactive Connectivity Establishment (ICE) <xref tar
get="RFC8445"/>, TCP/DTLS/BFCP, or UDP/TLS/BFCP, the straight-forward procedures
for connection management as UDP/BFCP described above apply.
TCP/TLS/BFCP follows the same procedures as TCP/BFCP and is described belo
w.</t>
</list></t>
<section title="TCP Connection Management" anchor="sec:tcp-connection">
<t> <t>
The management of the TCP connection used to transport BFCP messages is <xref target="RFC8843" format="default"/> defines how multiplexing of mult
performed using the SDP 'setup' and 'connection' attributes <xref target="RFC414 iple media streams can be negotiated. This specification does not define
5"/>. how BFCP streams can be multiplexed with other media streams. Therefore, a
The 'setup' attribute indicates which of the endpoints initiates the TCP BFCP stream <bcp14>MUST NOT</bcp14> be associated with a BUNDLE group <xref tar
connection. The 'connection' attribute handles TCP connection re-establishment. get="RFC8843" format="default"/>.
Note that BFCP-controlled media streams might be multiplexed with other me
dia streams.
</t> </t>
<t> <t>
The BFCP specification <xref target="I-D.ietf-bfcpbis-rfc4582bis"/> desc <xref target="RFC8859" format="default"/> defines the mux categories for t
ribes a number of situations when the TCP connection between a floor control cli he SDP
ent attributes defined in this specification, except for the 'bfcpver' attribu
and the floor control server needs to be re-established. However, that s te. <xref target="tab_mux-tbd" format="default"/> defines the mux category
pecification does not describe the re-establishment process because this process for the 'bfcpver' attribute:
depends on how the connection was established in the first place. Endpoi
nts using the offer/answer mechanism follow the following rules.
</t> </t>
<table anchor="tab_mux-tbd" align="center">
<name>Multiplexing Attribute Analysis</name>
<thead>
<tr>
<th align="left">Name</th>
<th align="left">Notes</th>
<th align="left">Level</th>
<th align="left">Mux Category</th>
</tr>
</thead>
<tbody>
<tr>
<td align="left">bfcpver</td>
<td align="left">Needs further analysis in a separate specification<
/td>
<td align="left">M</td>
<td align="left">TBD</td>
</tr>
</tbody>
</table>
</section>
<section anchor="sec_bfcp-connection" numbered="true" toc="default">
<name>BFCP Connection Management</name>
<t> <t>
When the existing TCP connection is closed and re-established following BFCP streams can use TCP or UDP as the underlying transport. Endpoints exc
the rules in <xref target="I-D.ietf-bfcpbis-rfc4582bis"/>, the floor control cli hanging BFCP messages over UDP send the BFCP messages towards the peer
ent using the connection address and port provided in the SDP "c=" and "m=" li
MUST send an offer towards the floor control server in order to re-estab nes. TCP connection management is more complicated and is described in
lish the connection. If a TCP connection cannot deliver a BFCP message and times the following section.
out,
the endpoint that attempted to send the message (i.e., the one that dete
cted the TCP timeout) MUST send an offer in order to re-establish the TCP connec
tion.
</t> </t>
<aside><t>Note: When using Interactive Connectivity Establishment
(ICE) <xref target="RFC8445" format="default"/>, TCP/DTLS/BFCP, or
UDP/TLS/BFCP, the straightforward procedures for connection management
via UDP/BFCP, as described above, apply.
TCP/TLS/BFCP follows the same procedures as TCP&wj;/BFCP and is described
below.</t></aside>
<section anchor="sec_tcp-connection" numbered="true" toc="default">
<name>TCP Connection Management</name>
<t>
The management of the TCP connection used to transport BFCP messages is
performed using the SDP 'setup' and 'connection' attributes <xref target="RFC414
5" format="default"/>.
The 'setup' attribute indicates which of the endpoints initiates the TCP
connection. The 'connection' attribute handles TCP connection re-establishment.
</t>
<t>
The BFCP specification <xref target="RFC8855" format="default"/> describ
es a number of situations when the TCP connection between a floor control client
and the floor control server needs to be re-established. However,
<xref target="RFC8855"/> does not describe the re-establishment
process, because this process
depends on how the connection was established in the first
place. Endpoints using the offer/answer mechanism follow the following
rules.</t>
<t>
When the existing TCP connection is closed and re-established following
the rules in <xref target="RFC8855" format="default"/>, the floor control client
<bcp14>MUST</bcp14> send an offer towards the floor control server in or
der to re-establish the connection. If a TCP connection cannot deliver a BFCP me
ssage and times out,
the endpoint that attempted to send the message (i.e., the one that dete
cted the TCP timeout) <bcp14>MUST</bcp14> send an offer in order to re-establish
the TCP connection.
</t>
<t>
Endpoints that use the offer/answer mechanism to negotiate TCP connectio
ns <bcp14>MUST</bcp14> support the 'setup' and 'connection' attributes.
</t>
</section>
</section>
<section anchor="sec_authentication" numbered="true" toc="default">
<name>TLS/DTLS Considerations</name>
<t> <t>
Endpoints that use the offer/answer mechanism to negotiate TCP connectio When DTLS is used with UDP, the generic procedures defined in <xref targe
ns MUST support the 'setup' and 'connection' attributes. t="RFC8842" sectionFormat="of" section="5"/>
<bcp14>MUST</bcp14> be followed.
</t> </t>
</section> <t>
</section>
<section title="TLS/DTLS Considerations" anchor="sec:authentication">
<t>
When DTLS is used with UDP, the generic procedures defined in Section 5 o
f <xref target="I-D.ietf-mmusic-dtls-sdp"/>
MUST be followed.
</t>
<t>
When TLS is used with TCP, once the underlying connection is established, the answerer always acts as the TLS server. When TLS is used with TCP, once the underlying connection is established, the answerer always acts as the TLS server.
If the TCP connection is lost, the active endpoint <xref target="RFC4583" /> is responsible for re-establishing the TCP connection. Unless a new If the TCP connection is lost, the active endpoint <xref target="RFC4583" format="default"/> is responsible for re-establishing the TCP connection. Unles s a new
TLS connection is negotiated, subsequent SDP offers and answers will not impact the previously negotiated TLS roles. TLS connection is negotiated, subsequent SDP offers and answers will not impact the previously negotiated TLS roles.
</t> </t>
<t><list style="empty"> <aside><t>Note: For TLS, it was decided to keep the original procedures in
<t> <xref target="RFC4583" format="default"/> to determine which endpoint
Note: For TLS, it was decided to keep the original procedures in <xref acts as the TLS server, in order to retain backward compatibility.</t>
target="RFC4583"/> to determine which endpoint </aside>
acts as the TLS server in order to retain backwards compatibility. </section>
</t> <section anchor="sec_ice-considerations" numbered="true" toc="default">
</list></t> <name>ICE Considerations</name>
</section>
<section title="ICE Considerations" anchor="sec:ice-considerations">
<t>
Generic SDP offer/answer procedures for Interactive Connectivity Establish
ment (ICE) are defined in <xref target="I-D.ietf-mmusic-ice-sip-sdp"/>.
</t>
<t>
When BFCP is used with UDP based ICE candidates <xref target="RFC8445"/> t
hen the procedures for UDP/TLS/BFCP are used.
</t>
<t>
When BFCP is used with TCP based ICE candidates <xref target="RFC6544"/> t
hen the procedures for TCP/DTLS/BFCP are used.
</t>
<t>
Based on the procedures defined in <xref target="I-D.ietf-mmusic-dtls-sdp"
/>, endpoints treat all ICE candidate pairs associated with a BFCP stream on top
of a DTLS association
as part of the same DTLS association. Thus, there will only be one BFCP ha
ndshake and one DTLS handshake even if there are multiple valid candidate pairs,
and if BFCP media is shifted between candidate pairs (including switching
between UDP to TCP candidate pairs) prior to nomination. If new candidates are a
dded,
they will also be part of the same DTLS association.
</t>
<t>
In order to maximize the likelihood of interoperability between the endpoi
nts, all ICE enabled BFCP-over-DTLS endpoints SHOULD
implement support for UDP/TLS/BFCP.
</t>
<t>
When an SDP offer or answer conveys multiple ICE candidates for a BFCP str
eam, UDP based candidates SHOULD be included and
the default candidate SHOULD be chosen from one of those UDP candidates. I
f UDP transport is used for the default candidate,
then the 'm' line proto value MUST be 'UDP/TLS/BFCP'. If TCP transport is
used for the default candidate, the 'm' line proto
value MUST be 'TCP/DTLS/BFCP'.
</t>
<t><list style="empty">
<t>Note: Usage of ICE with protocols other than UDP/TLS/BFCP and TCP/DTLS/
BFCP is outside of scope for this specification.</t>
</list></t>
</section>
<section title="SDP Offer/Answer Procedures" anchor="sec:oa-offer-answer-proc"
>
<t>
This section defines the SDP offer/answer <xref target="RFC3264"/> procedu
res for negotiating and establishing a BFCP stream.
Generic procedures for DTLS are defined in <xref target="I-D.ietf-mmusic-d
tls-sdp"/>. Generic procedures for TLS are defined
in <xref target="RFC8122"/>.
</t>
<t>
This section only defines the BFCP-specific procedures. Unless explicitly
stated otherwise, the procedures apply to an 'm' section describing a BFCP strea
m.
If an offer or answer contains multiple 'm' sections describing BFCP strea
ms, the procedures are applied independently to each stream.
</t>
<t>
Within this document, 'initial offer' refers to the first offer, within an
SDP session (e.g. a SIP
dialog when the Session Initiation Protocol (SIP) <xref target="RFC3261"/>
is used to carry SDP) in which the offerer
indicates that it wants to negotiate the establishment of a BFCP stream.
</t>
<t>
If the 'm' line 'proto' value is 'TCP/TLS/BFCP', 'TCP/DTLS/BFCP' or 'UDP/T
LS/BFCP', the offerer and answerer follow the generic procedures
defined in <xref target="RFC8122"/>.
</t>
<t>
If the 'm' line proto value is 'TCP/BFCP', 'TCP/TLS/BFCP', 'TCP/DTLS/TCP'
or 'UDP/TLS/BFCP', the offerer and answerer
use the SDP 'setup' attribute according to the procedures in <xref target=
"RFC4145"/>.
</t>
<t>
If the 'm' line proto value is 'TCP/BFCP', 'TCP/TLS/BFCP' or 'TCP/DTLS/BFC
P', the offerer and anwerer use
the SDP 'connection' attribute according to the procedures in <xref target
="RFC4145"/>.
</t>
<t><list style="empty">
<t>Note: The use of source-specific SDP parameters <xref target="RFC5576"/
> is not defined for BFCP streams.</t>
</list></t>
<section title="Generating the Initial SDP Offer" anchor="oa-gen-initial-off
er">
<t> <t>
When the offerer creates an initial offer, the offerer MUST include an S Generic SDP offer/answer procedures for ICE are defined in <xref target="R
DP 'floorctrl' attribute (<xref target="sec:floorctrl-attr"/>) FC8839" format="default"/>.
and an SDP 'bfcpver' attribute (<xref target="sec:bfcp-version-attr"/>)
in the 'm' section.
</t> </t>
<t> <t>
In addition, if the offerer includes an SDP 'floorctrl' attribute with ' s-only' or 'c-s' attribute values in the offer, the offerer: When BFCP is used with UDP-based ICE candidates <xref target="RFC8445" for mat="default"/>, the procedures for UDP/TLS/BFCP are used.
</t> </t>
<t><list style="symbols">
<t>MUST include an SDP 'confid' attribute (<xref target="sec:confid-at
tr"/>) in the 'm' section; and</t>
<t>MUST include an SDP 'userid' attribute (<xref target="sec:userid-at
tr"/>) in the 'm' section; and</t>
<t>MUST include an SDP 'floorid' attribute (<xref target="sec:floorid-
attr"/>) in the 'm' section; and</t>
<t>MUST include an SDP 'label' attribute (<xref target="RFC4574"/>) wi
th the 'm' section of each BFCP-controlled media stream.</t>
</list></t>
<t><list style="empty">
<t>
Note: If the offerer includes an SDP 'floorctrl' attribute with a 'c-s
' attribute value, or both a 'c-only' and a 's-only' attribute value in the offe
r,
the attribute values above will only be used if it is determined (<xre
f target="sec:floorctrl-attr"/>) that the offerer will act as floor control serv
er.
</t>
</list></t>
</section>
<section title="Generating the SDP Answer" anchor="oa-gen-answer">
<t> <t>
When the answerer receives an offer that contains an 'm' section describ When BFCP is used with TCP-based ICE candidates <xref target="RFC6544" for
ing a BFCP stream, the answerer MUST check whether it supports mat="default"/>, the procedures for TCP/DTLS/BFCP are used.
one or more of the BFCP versions supported by the offerer (<xref target=
"sec:bfcp-version-attr"/>). If the answerer does not support
any of the BFCP versions, it MUST NOT accept the 'm' section. Otherwise,
if the answerer accepts the 'm' section, it:
</t> </t>
<t><list style="symbols">
<t>MUST insert a corresponding 'm' section in the answer, with an iden
tical 'm' line proto value <xref target="RFC3264"/>; and</t>
<t>MUST include a 'bfcpver' attribute in the 'm' section. The versions
indicated by the answer MUST be the same or a subset of the versions indicated
by the offerer in the corresponding offer; and</t>
<t>MUST, if the offer contained an SDP 'floorctrl' attribute, include
a 'floorctrl' attribute in the 'm' section.</t>
</list></t>
<t> <t>
In addition, if the answerer includes an SDP 'floorctrl' attribute with Based on the procedures defined in <xref target="RFC8842" format="default"
an 's-only' attribute value in the answer, the answerer: />, endpoints treat all ICE candidate pairs associated with a BFCP stream on top
of a DTLS association
as part of the same DTLS association. Thus, there will only be one BFCP ha
ndshake and one DTLS handshake
even if there are multiple valid candidate pairs, and even if BFCP media
is shifted between candidate pairs (including switching between UDP
candidate pairs and TCP candidate pairs) prior to nomination. If new
candidates are added, they will also be part of the same DTLS association.
</t> </t>
<t><list style="symbols">
<t>MUST include an SDP 'confid' attribute in the 'm' section; and</t>
<t>MUST include an SDP 'userid' attribute in the 'm' section; and</t>
<t>MUST include an SDP 'floorid' attribute in the 'm' section; and</t>
<t>MUST include an SDP 'label' attribute in the 'm' section of each BF
CP-controlled media stream.</t>
</list></t>
<t><list style="empty">
<t>
Note: An offerer compliant with <xref target="RFC4583"/> might not inc
lude 'floorctrl' and 'bfcpver' attributes in offers, in which cases
the default values apply.
</t>
</list></t>
<t> <t>
Once the answerer has sent the answer, the answerer: In order to maximize the likelihood of interoperability between the endpoi
nts, all ICE-enabled BFCP-over-DTLS endpoints <bcp14>SHOULD</bcp14>
implement support for UDP/TLS/BFCP.
</t> </t>
<t><list style="symbols">
<t>MUST, if the answerer is the active endpoint, and if a TCP connecti
on associated with the 'm' section is to be established (or re-established),
initiate the establishing of the TCP connection; and</t>
<t>MUST, if the answerer is the active endpoint, and if an TLS/DTLS co
nnection associated with the 'm' section is to be established (or re-established
),
initiate the establishing of the TLS/DTLS connection (by sending a
ClientHello message).</t>
</list></t>
<t> <t>
If the answerer does not accept the 'm' section in the offer, it MUST as When an SDP offer or answer conveys multiple ICE candidates for a BFCP str
sign a zero port value to the 'm' line of the corresponding 'm' section in the a eam, UDP-based candidates <bcp14>SHOULD</bcp14> be included and
nswer. the default candidate <bcp14>SHOULD</bcp14> be chosen from one of those UD
In addition, the answerer MUST NOT establish a TCP connection or a TLS/D P candidates. If UDP transport is used for the default candidate,
TLS connection associated with the 'm' section. then the "m=" line proto value <bcp14>MUST</bcp14> be 'UDP/TLS/BFCP'. If T
CP transport is used for the default candidate, the "m=" line proto
value <bcp14>MUST</bcp14> be 'TCP/DTLS/BFCP'.
</t> </t>
<aside><t>Note: Usage of ICE with protocols other than UDP/TLS/BFCP and TCP/DTLS/BFCP is out of scope for this specification.</t></aside>
</section> </section>
<section anchor="sec_oa-offer-answer-proc" numbered="true" toc="default">
<section title="Offerer Processing of the SDP Answer" anchor="oa-offerer-pro <name>SDP Offer/Answer Procedures</name>
cessing-answer">
<t> <t>
When the offerer receives an answer that contains an 'm' section with a This section defines the SDP offer/answer <xref target="RFC3264" format="d
non-zero port value, describing a BFCP stream, the offerer: efault"/> procedures for negotiating and establishing a BFCP stream.
Generic procedures for DTLS are defined in <xref target="RFC8842" format="
default"/>. Generic procedures for TLS are defined
in <xref target="RFC8122" format="default"/>.
</t> </t>
<t><list style="symbols">
<t>MUST, if the offerer is the active endpoint, and if a TCP connectio
n associated with the 'm' section is to be established (or re-established),
initiate the establishing of the TCP connection; and</t>
<t>MUST, if the offerer is the active endpoint, and if an TLS/DTLS con
nection associated with the 'm' section is to be established (or re-established)
,
initiate the establishing of the TLS/DTLS connection (by sending a
ClientHello message).</t>
</list></t>
<t> <t>
Note: An answerer compliant with <xref target="RFC4583"/> might not incl This section only defines the BFCP-specific procedures. Unless explicitly
ude 'floorctrl' and 'bfcpver' attributes in answers, stated otherwise, the procedures apply to an "m=" section describing a BFCP stre
in which cases the default values apply. am.
If an offer or answer contains multiple "m=" sections describing BFCP stre
ams, the procedures are applied independently to each stream.
</t> </t>
<t> <t>
If the 'm' line in the answer contains a zero port value, or if the offe Within this document, 'initial offer' refers to the first offer within
rer for some other reason does not accept the answer (e.g., if the answerer only an SDP session (e.g., a Session Initiation Protocol (SIP)
indicates support of BFCP versions not supported by the offerer), the of dialog when SIP <xref target="RFC3261" format="default"/> is used to carry
ferer MUST NOT establish a TCP connection or a TLS/DTLS connection associated wi SDP) in which the offerer
th the 'm' section. indicates that it wants to negotiate the establishment of a BFCP stream.
</t> </t>
</section>
<section title="Modifying the Session" anchor="oa-mod-session">
<t> <t>
When an offerer sends an updated offer, in order to modify a previously If the "m=" line 'proto' value is 'TCP/TLS/BFCP', 'TCP/DTLS/BFCP', or 'UDP
established BFCP stream, it follows the procedures /TLS/BFCP', the offerer and answerer follow the generic procedures
in <xref target="oa-gen-initial-offer"/>, with the following exceptions: defined in <xref target="RFC8122" format="default"/>.
</t> </t>
<t><list style="symbols"> <t>
<t>If the BFCP stream is carried on top of TCP, and if the offerer doe If the "m=" line proto value is 'TCP/BFCP', 'TCP/TLS/BFCP', 'TCP&wj;/DTLS&
s not want to re-establish an existing TCP connection, the offerer MUST include wj;/TCP', or 'UDP/TLS/BFCP', the offerer and answerer
an SDP 'connection' attribute with a value of "existing", in the 'm use the SDP 'setup' attribute according to the procedures in <xref target=
' section; and</t> "RFC4145" format="default"/>.
<t>If the offerer wants to disable a previously established BFCP strea </t>
m, it MUST assign a zero port value to the 'm' line associated with the <t>
BFCP connection, following the procedures in <xref target="RFC3264" If the "m=" line proto value is 'TCP/BFCP', 'TCP/TLS/BFCP', or 'TCP/DTLS/B
/>.</t> FCP', the offerer and answerer use
</list></t> the SDP 'connection' attribute according to the procedures in <xref target
="RFC4145" format="default"/>.
</t>
<aside><t>Note: The use of source-specific SDP parameters <xref target="
RFC5576" format="default"/> is not defined for BFCP streams.</t></aside>
<section anchor="oa-gen-initial-offer" numbered="true" toc="default">
<name>Generating the Initial SDP Offer</name>
<t>
When the offerer creates an initial offer, the offerer <bcp14>MUST</bcp1
4> include an SDP 'floorctrl' attribute (<xref target="sec_floorctrl-attr" forma
t="default"/>)
and an SDP 'bfcpver' attribute (<xref target="sec_bfcp-version-attr" for
mat="default"/>) in the "m=" section.
</t>
<t>
In addition, if the offerer includes an SDP 'floorctrl' attribute with "
s-only" or "c-s" attribute values in the offer, the offerer
</t>
<ul spacing="normal">
<li><bcp14>MUST</bcp14> include an SDP 'confid' attribute (<xref targe
t="sec_confid-attr" format="default"/>) in the "m=" section,</li>
<li><bcp14>MUST</bcp14> include an SDP 'userid' attribute (<xref targe
t="sec_userid-attr" format="default"/>) in the "m=" section,</li>
<li><bcp14>MUST</bcp14> include an SDP 'floorid' attribute (<xref targ
et="sec_floorid-attr" format="default"/>) in the "m=" section, and</li>
<li><bcp14>MUST</bcp14> include an SDP 'label' attribute <xref target=
"RFC4574" format="default"/> with the "m=" section of each BFCP-controlled media
stream.</li>
</ul>
<aside><t>Note: If the offerer includes an SDP 'floorctrl' attribute wit
h a "c-s" attribute value, or both a "c-only" and an "s-only" attribute value in
the offer,
the attribute values above will only be used if it is determined
(<xref target="sec_floorctrl-attr" format="default"/>) that the
offerer will act as a floor control server.</t></aside>
</section>
<section anchor="oa-gen-answer" numbered="true" toc="default">
<name>Generating the SDP Answer</name>
<t>
When the answerer receives an offer that contains an "m=" section descri
bing a BFCP stream, the answerer <bcp14>MUST</bcp14> check whether it supports
one or more of the BFCP versions supported by the offerer (<xref target=
"sec_bfcp-version-attr" format="default"/>). If the answerer does not support
any of the BFCP versions, it <bcp14>MUST NOT</bcp14> accept the "m="
section. Otherwise, if the answerer accepts the "m=" section, the answere
r
</t>
<ul spacing="normal">
<li><bcp14>MUST</bcp14> insert a corresponding "m=" section in the
answer, with an identical "m=" line proto value <xref
target="RFC4566" format="default"/>,</li>
<li><bcp14>MUST</bcp14> include a 'bfcpver' attribute in the "m=" sect
ion; the versions indicated by the answer <bcp14>MUST</bcp14> be the same or a s
ubset of the versions indicated by the offerer in the corresponding offer, and</
li>
<li><bcp14>MUST</bcp14>, if the offer contained an SDP 'floorctrl' att
ribute, include a 'floorctrl' attribute in the "m=" section.</li>
</ul>
<t>
In addition, if the answerer includes an SDP 'floorctrl' attribute with
an "s-only" attribute value in the answer, the answerer
</t>
<ul spacing="normal">
<li><bcp14>MUST</bcp14> include an SDP 'confid' attribute in the "m="
section,</li>
<li><bcp14>MUST</bcp14> include an SDP 'userid' attribute in the "m="
section,</li>
<li><bcp14>MUST</bcp14> include an SDP 'floorid' attribute in the "m="
section, and</li>
<li><bcp14>MUST</bcp14> include an SDP 'label' attribute in the "m=" s
ection of each BFCP-controlled media stream.</li>
</ul>
<aside><t>Note: An offerer compliant with <xref target="RFC4583" format
="default"/> might not include 'floorctrl' and 'bfcpver' attributes in offers, i
n which case
the default values apply.</t></aside>
<t>
Once the answerer has sent the answer, the answerer
</t>
<ul spacing="normal">
<li><bcp14>MUST</bcp14>, if the answerer is the active endpoint and if
a TCP connection associated with the "m=" section is to be established (or re-e
stablished),
initiate the establishment of the TCP connection, and</li>
<li><bcp14>MUST</bcp14>, if the answerer is the active endpoint and if
a TLS/DTLS connection associated with the "m=" section is to be established (or
re-established),
initiate the establishment of the TLS/DTLS connection (by sending a
ClientHello message).</li>
</ul>
<t>
If the answerer does not accept the "m=" section in the offer, it <bcp14
>MUST</bcp14> assign a zero port value to the "m=" line of the corresponding "m=
" section in the answer.
In addition, the answerer <bcp14>MUST NOT</bcp14> establish a TCP connec
tion or a TLS/DTLS connection associated with the "m=" section.
</t>
</section>
<section anchor="oa-offerer-processing-answer" numbered="true" toc="defaul
t">
<name>Offerer Processing of the SDP Answer</name>
<t>
When the offerer receives an answer that contains an "m=" section
describing a BFCP stream and with a non-zero port value in the
"m=" line, the offerer</t>
<ul spacing="normal">
<li><bcp14>MUST</bcp14>, if the offerer is the active endpoint and if
a TCP connection associated with the "m=" section is to be established (or re-es
tablished),
initiate the establishment of the TCP connection, and</li>
<li><bcp14>MUST</bcp14>, if the offerer is the active endpoint and if
a TLS/DTLS connection associated with the "m=" section is to be established (or
re-established),
initiate the establishment of the TLS/DTLS connection (by sending a
ClientHello message).</li>
</ul>
<aside><t>Note: An answerer compliant with <xref target="RFC4583" format
="default"/> might not include 'floorctrl' and 'bfcpver' attributes in answers,
in which case the default values apply.</t></aside>
<t>
If the "m=" line in the answer contains a zero port value or if the offe
rer for some other reason does not accept the answer (e.g., if the answerer only
indicates support of BFCP versions not supported by the offerer), the of
ferer <bcp14>MUST NOT</bcp14> establish a TCP connection or a TLS/DTLS connectio
n associated with the "m=" section.
</t>
</section>
<section anchor="oa-mod-session" numbered="true" toc="default">
<name>Modifying the Session</name>
<t>
When an offerer sends an updated offer, in order to modify a previously
established BFCP stream, it follows the procedures
in <xref target="oa-gen-initial-offer" format="default"/>, with the foll
owing exceptions:
</t>
<ul spacing="normal">
<li>If the BFCP stream is carried on top of TCP and if the offerer
does not want to re-establish an existing TCP connection, the
offerer <bcp14>MUST</bcp14> include in the "m=" section
an SDP 'connection' attribute with a value of "existing", and</li>
<li>If the offerer wants to disable a previously established BFCP stre
am, it <bcp14>MUST</bcp14> assign a zero port value to the "m=" line associated
with the
BFCP connection, following the procedures in <xref target="RFC3264"
format="default"/>.</li>
</ul>
</section>
</section> </section>
<section anchor="sec_example" numbered="true" toc="default">
</section> <name>Examples</name>
<t>For the purpose of brevity, the main portion of the session description
<section title="Examples" anchor="sec:example"> is omitted in the examples, which only show "m=" sections and their "m=" lines
<t>For the purpose of brevity, the main portion of the session description i and attributes.</t>
s omitted in the examples, which only show 'm' sections and their 'm' lines and <t>The following is an example of an offer sent by a conference server to
attributes.</t> a client.</t>
<t>The following is an example of an offer sent by a conference server to a <sourcecode name="" type="sdp"><![CDATA[
client.</t>
<figure>
<artwork>
m=application 50000 TCP/TLS/BFCP * m=application 50000 TCP/TLS/BFCP *
a=setup:actpass a=setup:actpass
a=connection:new a=connection:new
a=fingerprint:sha-256 \ a=fingerprint:sha-256 \
19:E2:1C:3B:4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73:04: \ 19:E2:1C:3B:4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73:04: \
BB:05:2F:70:9F:04:A9:0E:05:E9:26:33:E8:70:88:A2 BB:05:2F:70:9F:04:A9:0E:05:E9:26:33:E8:70:88:A2
a=floorctrl:c-only s-only a=floorctrl:c-only s-only
a=confid:4321 a=confid:4321
a=userid:1234 a=userid:1234
a=floorid:1 mstrm:10 a=floorid:1 mstrm:10
a=floorid:2 mstrm:11 a=floorid:2 mstrm:11
a=bfcpver:1 2 a=bfcpver:1 2
m=audio 50002 RTP/AVP 0 m=audio 50002 RTP/AVP 0
a=label:10 a=label:10
m=video 50004 RTP/AVP 31 m=video 50004 RTP/AVP 31
a=label:11 a=label:11 ]]></sourcecode>
</artwork> <t>Note that due to RFC formatting conventions, this document splits the
</figure> SDP entries across lines whose content would exceed the maximum line
<t>Note that due to RFC formatting conventions, this document splits SDP acr length. A backslash character ("\") marks where this line folding has take
oss lines whose content would exceed 72 characters. A backslash character marks n place. This backslash and its trailing CRLF and whitespace would not appear in
where this line folding has taken place. This backslash and its trailing CRLF an actual SDP content.</t>
d whitespace would not appear in actual SDP content.</t> <t>The following is the answer returned by the client.</t>
<t>The following is the answer returned by the client.</t> <sourcecode name="" type="sdp"><![CDATA[
<figure>
<artwork>
m=application 9 TCP/TLS/BFCP * m=application 9 TCP/TLS/BFCP *
a=setup:active a=setup:active
a=connection:new a=connection:new
a=fingerprint:sha-256 \ a=fingerprint:sha-256 \
6B:8B:F0:65:5F:78:E2:51:3B:AC:6F:F3:3F:46:1B:35: \ 6B:8B:F0:65:5F:78:E2:51:3B:AC:6F:F3:3F:46:1B:35: \
DC:B8:5F:64:1A:24:C2:43:F0:A1:58:D0:A1:2C:19:08 DC:B8:5F:64:1A:24:C2:43:F0:A1:58:D0:A1:2C:19:08
a=floorctrl:c-only a=floorctrl:c-only
a=bfcpver:1 a=bfcpver:1
m=audio 55000 RTP/AVP 0 m=audio 55000 RTP/AVP 0
m=video 55002 RTP/AVP 31 m=video 55002 RTP/AVP 31 ]]></sourcecode>
</artwork>
</figure>
<t>A similar example using unreliable transport and DTLS is shown below, where t <t>A similar example using an unreliable transport and DTLS is shown below
he offer is sent from a client.</t> , where the offer is sent from a client.</t>
<figure> <sourcecode name="" type="sdp"><![CDATA[
<artwork>
m=application 50000 UDP/TLS/BFCP * m=application 50000 UDP/TLS/BFCP *
a=setup:actpass a=setup:actpass
a=dtls-id:abc3dl a=dtls-id:abc3dl
a=fingerprint:sha-256 \ a=fingerprint:sha-256 \
19:E2:1C:3B:4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73:04: \ 19:E2:1C:3B:4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73:04: \
BB:05:2F:70:9F:04:A9:0E:05:E9:26:33:E8:70:88:A2 BB:05:2F:70:9F:04:A9:0E:05:E9:26:33:E8:70:88:A2
a=floorctrl:c-only s-only a=floorctrl:c-only s-only
a=confid:4321 a=confid:4321
a=userid:1234 a=userid:1234
a=floorid:1 mstrm:10 a=floorid:1 mstrm:10
a=floorid:2 mstrm:11 a=floorid:2 mstrm:11
a=bfcpver:1 2 a=bfcpver:1 2
m=audio 50002 RTP/AVP 0 m=audio 50002 RTP/AVP 0
a=label:10 a=label:10
m=video 50004 RTP/AVP 31 m=video 50004 RTP/AVP 31
a=label:11 a=label:11 ]]></sourcecode>
</artwork>
</figure> <t>The following is the answer returned by the server.</t>
<t>The following is the answer returned by the server.</t> <sourcecode name="" type="sdp"><![CDATA[
<figure>
<artwork>
m=application 55000 UDP/TLS/BFCP * m=application 55000 UDP/TLS/BFCP *
a=setup:active a=setup:active
a=dtls-id:abc3dl a=dtls-id:abc3dl
a=fingerprint:sha-256 \ a=fingerprint:sha-256 \
6B:8B:F0:65:5F:78:E2:51:3B:AC:6F:F3:3F:46:1B:35: \ 6B:8B:F0:65:5F:78:E2:51:3B:AC:6F:F3:3F:46:1B:35: \
DC:B8:5F:64:1A:24:C2:43:F0:A1:58:D0:A1:2C:19:08 DC:B8:5F:64:1A:24:C2:43:F0:A1:58:D0:A1:2C:19:08
a=floorctrl:s-only a=floorctrl:s-only
a=confid:4321 a=confid:4321
a=userid:1234 a=userid:1234
a=floorid:1 mstrm:10 a=floorid:1 mstrm:10
a=floorid:2 mstrm:11 a=floorid:2 mstrm:11
a=bfcpver:2 a=bfcpver:2
m=audio 55002 RTP/AVP 0 m=audio 55002 RTP/AVP 0
m=video 55004 RTP/AVP 31 m=video 55004 RTP/AVP 31 ]]></sourcecode>
</artwork> </section>
</figure> <section anchor="sec_security" numbered="true" toc="default">
</section> <name>Security Considerations</name>
<t>The BFCP specification <xref target="RFC8855" format="default"/>, SDP
<section title="Security Considerations" anchor="sec:security"> specification <xref target="RFC4566" format="default"/>, and
<t>The BFCP <xref target="I-D.ietf-bfcpbis-rfc4582bis"/>, SDP <xref target=" offer/answer specification <xref target="RFC3264" format="default"/> discu
RFC4566"/>, and offer/answer <xref target="RFC3264"/> ss security issues related to BFCP, SDP, and offer/answer, respectively. In addi
specifications discuss security issues related to BFCP, SDP, and offer/answe tion, <xref target="RFC4145" format="default"/>
r, respectively. In addition, <xref target="RFC4145"/> and <xref target="RFC8122" format="default"/> discuss security issues relate
and <xref target="RFC8122"/> discuss security issues related to the establis d to the establishment of TCP and TLS connections using an offer/answer
hment of TCP and TLS connections using an offer/answer
model. Furthermore, when using DTLS over UDP, the generic offer/answer consi derations defined in model. Furthermore, when using DTLS over UDP, the generic offer/answer consi derations defined in
<xref target="I-D.ietf-mmusic-dtls-sdp"/> MUST be followed.</t> <xref target="RFC8842" format="default"/> <bcp14>MUST</bcp14> be followed.</
<t>The usage of certain proto values in the SDP offer/answer negotiation wil t>
l result in a BFCP stream that is not protected by <t>The usage of certain proto values in the SDP offer/answer negotiation w
ill result in a BFCP stream that is not protected by
TLS or DTLS. Operators will need to provide integrity protection and confide ntiality protection of the BFCP stream using other means.</t> TLS or DTLS. Operators will need to provide integrity protection and confide ntiality protection of the BFCP stream using other means.</t>
<t>The generic security considerations associated with SDP attributes are de <t>The generic security considerations associated with SDP attributes are
fined in <xref target="RFC3264"/>. While the attributes defined in <xref target="RFC3264" format="default"/>. While the attributes
defined in this specification do not reveal information about the content of defined in this specification do not reveal information about the content of
individual BFCP controlled media streams, they do reveal individual BFCP-controlled media streams, they do reveal
which media streams will be BFCP controlled.</t> which media streams will be BFCP controlled.</t>
</section>
<section anchor="sec_iana" numbered="true" toc="default">
<name>IANA Considerations</name>
<t>This document registers three new values in the "proto"
subregistry within the "Session Description Protocol (SDP)
Parameters" registry: 'TCP/DTLS/BFCP', 'UDP/BFCP', and 'UDP/TLS/BFCP' (see <xref
target="sec_proto-reg"/>).</t>
<t>This document also registers a new SDP attribute in the "att-field"
subregistry within the "Session Description Protocol (SDP) Parameters"
registry: 'bfcpver' (see <xref target="sec_bfcp-version-attr"/>).</t>
<t>The remaining values are unchanged from <xref target="RFC4582"/>, except
that the references have been updated to refer to this document.</t>
</section> <section anchor="sec_proto-reg" numbered="true" toc="default">
<name>Registration of SDP 'proto' Values</name>
<section title="IANA Considerations" anchor="sec:iana"> <t>The IANA has registered three new values in the SDP
<t><list style="empty"> 'proto' field under the "Session Description Protocol (SDP)
<t>[Editorial note: The changes in <xref target="sec:proto-reg"/> instruct Parameters" registry.</t>
the IANA to register the three new values TCP/DTLS/BFCP, UDP/BFCP and UDP/TLS/B <table anchor="tab_proto-iana" align="center">
FCP for the SDP 'proto' field. The new section <xref target="sec:bfcp-version-at <name>Values for the SDP 'proto' Field</name>
tr"/> registers a new SDP "bfcpver" attribute. The rest is unchanged from <xref <thead>
target="RFC4582"/>.]</t> <tr>
</list></t> <th align="left">Value</th>
<th align="center">Reference</th>
</tr>
</thead>
<tbody>
<tr>
<td align="left">TCP/BFCP</td>
<td align="center">RFC 8856</td>
</tr>
<tr>
<td align="left">TCP/DTLS/BFCP</td>
<td align="center">RFC 8856</td>
</tr>
<tr>
<td align="left">TCP/TLS/BFCP</td>
<td align="center">RFC 8856</td>
</tr>
<tr>
<td align="left">UDP/BFCP</td>
<td align="center">RFC 8856</td>
</tr>
<tr>
<td align="left">UDP/TLS/BFCP</td>
<td align="center">RFC 8856</td>
</tr>
</tbody>
</table>
</section>
<section numbered="true" toc="default">
<name>Registration of the SDP 'floorctrl' Attribute</name>
<t>
This document defines the SDP 'floorctrl' attribute.
Details regarding this attribute are provided in <xref target="sec_floor
ctrl-attr" format="default"/>.
</t>
</section>
<section numbered="true" toc="default">
<name>Registration of the SDP 'confid' Attribute</name>
<t>
This document defines the SDP 'confid' attribute.
Details regarding this attribute are provided in <xref target="sec_confi
d-attr" format="default"/>.
</t>
</section>
<section numbered="true" toc="default">
<name>Registration of the SDP 'userid' Attribute</name>
<t>
This document defines the SDP 'userid' attribute.
Details regarding this attribute are provided in <xref target="sec_useri
d-attr" format="default"/>.
</t>
</section>
<section numbered="true" toc="default">
<name>Registration of the SDP 'floorid' Attribute</name>
<t>
This document defines the SDP 'floorid' attribute.
Details regarding this attribute are provided in <xref target="sec_floor
id-attr" format="default"/>.
</t>
</section>
<section numbered="true" toc="default">
<name>Registration of the SDP 'bfcpver' Attribute</name>
<t>
This document defines the SDP 'bfcpver' attribute.
Details regarding this attribute are provided in <xref target="sec_bfcp-
version-attr" format="default"/>.
</t>
</section>
</section>
<section anchor="sec_changes" numbered="true" toc="default">
<name>Changes from RFC 4583</name>
<t>The technical changes and other fixes from <xref
target="RFC4583" format="default"/> are listed below.</t>
<t>The main purpose of this work was to add signaling support necessary
to support BFCP over an unreliable transport, as described in <xref target
="RFC8855" format="default"/>, resulting in the following changes:</t>
<ul>
<li><t>Fields in the "m=" Line (<xref target="sec_m-line" format="default"/
>):</t>
<t>This section has been rewritten to remove reference to the exclusivi
ty
of TCP as a transport for BFCP streams. The proto field values
'TCP/DTLS/BFCP', 'UDP/BFCP', and 'UDP/TLS/BFCP' have been added.</t></li
>
<li><t>Security Considerations (<xref target="sec_security" format="default
"/>):</t>
<t>For the DTLS-over-UDP case, we direct the reader to existing conside
rations
and requirements for the offer&wj;/answer exchange as provided in <xref
target="RFC8842" format="default"/>.</t></li>
<li><t>Registration of SDP 'proto' Values (<xref target="sec_proto-reg" for
mat="default"/>):</t>
<t>This document registers the three new values 'TCP/DTLS/BFCP', 'UDP/B
FCP', and
'UDP/TLS/BFCP' in the "Session Description Protocol (SDP) Parameters" re
gistry.</t></li>
<li><t>SDP 'bfcpver' Attribute (<xref target="sec_bfcp-version-attr" format
="default"/>):</t>
<t>A new 'bfcpver' SDP media-level attribute has been added, in order t
o
signal the supported version number.</t></li>
</ul>
<section title="Registration of SDP 'proto' Values" anchor="sec:proto-reg"> <t>In addition to the changes associated with support of BFCP over an
<t>The IANA is requested to register the following values for the SDP 'pro unreliable transport, the possibility that an endpoint can act as both a
to' field under the Session Description Protocol (SDP) Parameters registry:</t> floor control client and a floor control server at the same time has
been removed. An endpoint will now take the same role for all BFCP-controlle
d streams associated with the BFCP stream.</t>
<t>Clarifications and bug fixes:</t>
<texttable title="Values for the SDP 'proto' field" anchor="tab:proto-iana <ul>
"> <li><t>Erratum ID 712 (Sections&nbsp;<xref target="RFC4583" section="3"
<ttcol>Value</ttcol> sectionFormat="bare"/> and <xref target="RFC4583" section="10"
<ttcol align="center">Reference</ttcol> sectionFormat="bare"/> of <xref target="RFC4583"/>; see <xref target="Err712"/>
for details):</t>
<c>TCP/BFCP</c> <t>Do not use language such as 'used in an "m=" line' when discussing a
<c>[RFC XXXX]</c> n SDP attribute; instead, make clear that the attribute is a
media-level attribute.</t></li>
<li><t>Spelling corrected in the first SDP example in <xref target="RFC
4583" sectionFormat="of" section="9"/>:</t>
<t>Do not use 'm-stream' as listed in the first SDP example in <xref
target="RFC4583"/>; instead, use the correct 'mstrm'
as specified in <xref target="sec_example" format="default"/> of this
document. However, we recommend continuing to interpret 'm-stream', if r
eceived,
because it is still present in some implementations.</t></li>
<li><t>Assorted clarifications (throughout the document):</t>
<t>Language clarifications were made as a result of reviews. Also,
normative language was "tightened" where appropriate, i.e., changed
from "<bcp14>SHOULD</bcp14>" strength to "<bcp14>MUST</bcp14>" in a
number of places.</t></li>
</ul>
</section>
</middle>
<back>
<references>
<name>References</name>
<references>
<name>Normative References</name>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.2119.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.5234.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.3261.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.3264.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4145.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4574.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8122.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4566.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.6347.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4571.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.6544.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4582.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4583.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8174.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8445.
xml"/>
<c>TCP/DTLS/BFCP</c> <!-- draft-ietf-mmusic-ice-sip-sdp-39 RFC-to-be 8839 -->
<c>[RFC XXXX]</c>
<c>TCP/TLS/BFCP</c> <reference anchor='RFC8839' target="https://www.rfc-editor.org/info/rfc8839">
<c>[RFC XXXX]</c> <front>
<title>Session Description Protocol (SDP) Offer/Answer Procedures for Interactiv
e Connectivity Establishment (ICE)</title>
<c>UDP/BFCP</c> <author initials='M' surname='Petit-Huguenin' fullname='Marc Petit-Huguenin'>
<c>[RFC XXXX]</c> <organization />
</author>
<c>UDP/TLS/BFCP</c> <author initials='S' surname='Nandakumar' fullname='Suhas Nandakumar'>
<c>[RFC XXXX]</c> <organization />
</texttable> </author>
</section>
<section title="Registration of the SDP 'floorctrl' Attribute"> <author initials='C' surname='Holmberg' fullname='Christer Holmberg'>
<t> <organization />
This document defines the SDP attribute,'floorctrl'. </author>
The details of the attribute are defined in <xref target="sec:floorctrl-
attr"/>.
</t>
</section>
<section title="Registration of the SDP 'confid' Attribute"> <author initials='A' surname='Keränen' fullname='Ari Keränen'>
<t> <organization />
This document defines the SDP attribute,'confid'. </author>
The details of the attribute are defined in <xref target="sec:confid-att
r"/>.
</t>
</section>
<section title="Registration of the SDP 'userid' Attribute"> <author initials='R' surname='Shpount' fullname='Roman Shpount'>
<t> <organization />
This document defines the SDP attribute,'userid'. </author>
The details of the attribute are defined in <xref target="sec:userid-att
r"/>.
</t>
</section>
<section title="Registration of the SDP 'floorid' Attribute"> <date month="May" year="2020"/>
<t>
This document defines the SDP attribute,'floorid'.
The details of the attribute are defined in <xref target="sec:floorid-at
tr"/>.
</t>
</section>
<section title="Registration of the SDP 'bfcpver' Attribute"> </front>
<t> <seriesInfo name="RFC" value="8839"/>
This document defines the SDP attribute,'bfcpver'. <seriesInfo name="DOI" value="10.17487/RFC8839"/>
The details of the attribute are defined in <xref target="sec:bfcp-versi
on-attr"/>.
</t>
</section>
</section>
<section title="Changes from RFC 4583" anchor="sec:changes"> </reference>
<t>Following is the list of technical changes and other fixes from <xref tar
get="RFC4583"/>.</t>
<t>Main purpose of this work was to add signaling support necessary to suppo
rt BFCP over unreliable transport, as described in <xref target="I-D.ietf-bfcpbi
s-rfc4582bis"/>, resulting in the following changes:</t>
<t><list style="numbers">
<t>Fields in the 'm' line (<xref target="sec:m-line"/>):<vspace/>
The section is re-written to remove reference to the exclusivity of TC
P as a transport for BFCP streams. The proto field values TCP/DTLS/BFCP, UDP/BFC
P and UDP/TLS/BFCP added.</t>
<t>Security Considerations (<xref target="sec:security"/>):<vspace/>
For the DTLS over UDP case, mention existing considerations and requir
ements for the offer/answer exchange in <xref target="I-D.ietf-mmusic-dtls-sdp"/
>.</t>
<t>Registration of SDP 'proto' Values (<xref target="sec:proto-reg"/>):<
vspace/>
Register the three new values TCP/DTLS/BFCP, UDP/BFCP and UDP/TLS/BFCP
in the SDP parameters registry.</t>
<t>BFCP Version Negotiation (<xref target="sec:bfcp-version-attr"/>):<vs
pace/>
A new 'bfcpver' SDP media-level attribute is added in order to signal
supported version number.</t>
</list></t>
<t>In addition to the changes associated with support of BFCP over unreliabl
e transport, the possibility for an endpoint to act as both floor control client
and floor control server at the same time has
been removed. An endpoint will now take the same role for all BFCP-controlle
d streams associated with the BFCP stream.</t>
<t>Clarification and bug fixes:</t>
<t><list style="numbers">
<t>Errata ID: 712 (<xref target="sec:server-determination"/> and <xref t
arget="sec:oa-offer-answer-proc"/>):<vspace/>
Language clarification. Don't use terms like an SDP attribute is "used
in an 'm' line", instead make clear that the attribute is a media-level attribu
te.</t>
<t>Fix typo in example (<xref target="sec:example"/>):<vspace/>
Do not use 'm-stream' in the SDP example, use the correct 'mstrm' as s
pecified in <xref target="sec:example"/>. Recommend interpreting 'm-stream' if i
t is received, since it is present in some implementations.</t>
<t>Assorted clarifications (Across the document):<vspace/>
Language clarifications as a result of reviews. Also, the normative la
nguage where tightened where appropriate, i.e. changed from SHOULD strength to M
UST in a number of places.</t>
</list></t>
</section>
<section title="Acknowledgements" anchor="sec:acks"> <!-- draft-ietf-bfcpbis-rfc4582bis RFC-to-be 8855 -->
<t>Joerg Ott, Keith Drage, Alan Johnston, Eric Rescorla, Roni Even, and Osca <reference anchor="RFC8855" target="https://www.rfc-editor.org/info/rfc8855">
r Novo provided useful ideas for the original <xref target="RFC4583"/>. The auth
ors also acknowledge contributions to the revision of BFCP for use over an unrel
iable transport from Geir Arne Sandbakken, Charles Eckel, Alan Ford, Eoin McLeod
and Mark Thompson. Useful and important final reviews were done by Ali C. Begen
, Mary Barnes and Charles Eckel. In the final stages, Roman Shpount made a consi
derable effort in adding proper ICE support and considerations.</t>
</section>
</middle>
<back> <front>
<references title="Normative References"> <title>The Binary Floor Control Protocol (BFCP)</title>
<?rfc include="reference.RFC.2119" ?>
<?rfc include="reference.RFC.5234" ?> <author initials="G." surname="Camarillo" fullname="">
<?rfc include="reference.RFC.3261" ?> <organization />
<?rfc include="reference.RFC.3264" ?> </author>
<?rfc include="reference.RFC.4145" ?>
<?rfc include="reference.RFC.4574" ?> <author initials="K." surname="Drage" fullname="Keith Drage">
<?rfc include="reference.RFC.8122" ?> <organization />
<?rfc include="reference.RFC.4566" ?> </author>
<?rfc include="reference.RFC.6347" ?>
<?rfc include="reference.RFC.4571" ?> <author initials="T." surname="Kristensen" fullname="Tom Kristensen">
<?rfc include="reference.RFC.6544" ?> <organization />
<?rfc include="reference.RFC.4582" ?> </author>
<?rfc include="reference.RFC.4583" ?>
<?rfc include="reference.RFC.8174" ?> <author initials="J." surname="Ott" fullname="Jörg Ott">
<?rfc include="reference.RFC.8445" ?> <organization />
<?rfc include="reference.I-D.draft-ietf-mmusic-ice-sip-sdp-24"?> </author>
<?rfc include="reference.I-D.draft-ietf-bfcpbis-rfc4582bis-16" ?>
<?rfc include="reference.I-D.draft-ietf-mmusic-dtls-sdp-32" ?> <author initials="C." surname="Eckel" fullname="Charles Eckel">
<?rfc include="reference.I-D.draft-ietf-mmusic-sdp-mux-attributes-17" ?> <organization />
</references> </author>
<references title="Informational References">
<?rfc include="reference.RFC.5576" ?> <date month="May" year="2020" />
<?rfc include="reference.I-D.draft-ietf-mmusic-sdp-bundle-negotiation-53" ?> </front>
</references> <seriesInfo name="RFC" value="8855" />
</back> <seriesInfo name="DOI" value="10.17487/RFC8855"/>
</reference>
<!-- draft-ietf-mmusic-dtls-sdp RFC-to-be 8842 -->
<reference anchor="RFC8842" target="https://www.rfc-editor.org/info/rfc8842">
<front>
<title>Session Description Protocol (SDP) Offer/Answer Considerations for
Datagram Transport Layer Security (DTLS) and Transport Layer Security (TLS)</tit
le>
<author initials="C." surname="Holmberg" fullname="Christer Holmberg">
<organization />
</author>
<author initials="R." surname="Shpount" fullname="Roman Shpount">
<organization />
</author>
<date month="May" year="2020" />
</front>
<seriesInfo name="RFC" value="8842" />
<seriesInfo name="DOI" value="10.17487/RFC8842"/>
</reference>
<!-- draft-ietf-mmusic-sdp-mux-attributes-17 (RFC 8859) -->
<reference anchor="RFC8859" target="https://www.rfc-editor.org/info/rfc8859">
<front>
<title>A Framework for SDP Attributes When Multiplexing</title>
<author initials="S" surname="Nandakumar" fullname="Suhas Nandakumar">
<organization/>
</author>
<date month="May" year="2020"/>
</front>
<seriesInfo name="DOI" value="10.17487/RFC8859"/>
<seriesInfo name="RFC" value="8859"/>
</reference>
</references>
<references>
<name>Informative References</name>
<reference anchor="Err712" quote-title="false"
target="https://www.rfc-editor.org/errata/eid712">
<front>
<title>Erratum ID 712</title>
<author><organization>RFC Errata</organization></author>
</front>
<refcontent>RFC 4583</refcontent>
</reference>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.5576.
xml"/>
<!-- draft-ietf-mmusic-sdp-bundle-negotiation (RFC 8843) -->
<reference anchor="RFC8843" target="https://www.rfc-editor.org/info/rfc8843">
<front>
<title>Negotiating Media Multiplexing Using the Session Description Protocol
(SDP)</title>
<author initials="C" surname="Holmberg" fullname="Christer Holmberg">
<organization/>
</author>
<author initials="H" surname="Alvestrand" fullname="Harald Alvestrand">
<organization/>
</author>
<author initials="C" surname="Jennings" fullname="Cullen Jennings">
<organization/>
</author>
<date month="May" year="2020"/>
</front>
<seriesInfo name="RFC" value="8843"/>
<seriesInfo name="DOI" value="10.17487/RFC8843"/>
</reference>
</references>
</references>
<section anchor="sec_acks" numbered="false" toc="default">
<name>Acknowledgements</name>
<t><contact fullname="Joerg Ott"/>, <contact fullname="Keith Drage"/>,
<contact fullname="Alan Johnston"/>, <contact fullname="Eric
Rescorla"/>, <contact fullname="Roni Even"/>, and <contact
fullname="Oscar Novo"/> provided useful ideas for the original <xref
target="RFC4583" format="default"/>. The authors also acknowledge
contributions to the revision of BFCP for use over an unreliable
transport from <contact fullname="Geir Arne Sandbakken"/>, <contact
fullname="Charles Eckel"/>, <contact fullname="Alan Ford"/>, <contact
fullname="Eoin McLeod"/>, and <contact fullname="Mark Thompson"/>. Useful
and important final reviews were done by <contact fullname="Ali
C.&nbsp;Begen"/>, <contact fullname="Mary Barnes"/>, and <contact
fullname="Charles Eckel"/>. In the final stages, <contact fullname="Roman
Shpount"/> made a considerable effort in adding proper ICE support and considera
tions.</t>
</section>
</back>
</rfc> </rfc>
 End of changes. 102 change blocks. 
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