| Internet-Draft | IOAM-DEX Over MNA | September 2022 |
| Mirsky & Boucadair | Expires 26 March 2023 | [Page] |
In-Situ Operations, Administration, and Maintanence (IOAM), defined in RFC 9197, is an on-path telemetry method to collect and transport the operational state and telemetry information that can be used in calculating various performance metrics. IOAM Direct Export (IOAM-DEX) is one of IOAM Trace-Option types, in which generated telemetry information is exported according to a local policy. MPLS Network Actions (MNA) techniques are meant to indicate actions to be performed on any combination of Label Switched Paths (LSPs), MPLS packets, and the node itself, and also to transfer data needed for these actions. This document explores how MNA can be used for collecting on-path operational state and telemetry information using IOAM-DEX Trace-Option.¶
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.¶
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.¶
Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."¶
This Internet-Draft will expire on 26 March 2023.¶
Copyright (c) 2022 IETF Trust and the persons identified as the document authors. All rights reserved.¶
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.¶
In-Situ OAM (IOAM) [RFC9197] is an on-path telemetry method to collect and transport the operational state and telemetry information that can be used in calculating various performance metrics. Several IOAM Trace-Option types (e.g., Pre-allocated and Incremental) use the user packet themselves to collect the operational state and telemetry information. Such a mechanism transports the collected information to an IOAM decapsulating node (typically, located at the edge of the IOAM domain within the data packet). IOAM Direct Export (IOAM-DEX) [I-D.ietf-ippm-ioam-direct-export] is an IOAM Trace-Option type in which the operational state and telemetry information are exported according to a local policy. MPLS Network Actions (MNA) techniques [I-D.ietf-mpls-mna-fwk] indicate actions to be performed on any combination of Label Switched Paths (LSPs), MPLS packets, the node itself, and also allow for the transfer of data needed for these actions.¶
This document describes how MNA can be used for collecting on-path operational state and telemetry information using IOAM-DEX Trace-Option. Specifying the mechanism of exporting collected information is outside the scope of this document.¶
IOAM: In-Situ OAM¶
IOAM-DEX: IOAM Direct Export¶
ISD: In-Stack Data¶
LSP: Label Switched Path¶
MPLS: Multiprotocol Label Switching¶
MNA: MPLS Network Actions¶
PSD: Post-Stack Data¶
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶
Pre-allocated, Incremental, and Edge-to-Edge IOAM Trace-Option types [RFC9197] use user packets to collect and transport the operational state and telemetry information. In some environments, for example, data center networks, this technique is useful as the available bandwidth, and the use of jumbo frames can accommodate the increase of the packet payload. But for other use cases in which network resources are closely controlled, the use of in-band channels for collecting and transporting the telemetry information may noticeably decrease the cost-efficiency of network operations. Although the operational state and telemetry information are essential for network automation (Section 4 of [RFC8969]), its delivery is not as critical as user packets. As such, collecting and transporting the operational state and telemetry information out-of-band using the management plane is a viable option for some environments. IOAM-DEX [I-D.ietf-ippm-ioam-direct-export] is used to collect IOAM data defined in [RFC9197]. The processing and transport of the collected information are controlled by a local policy which is outside the scope of this specification.¶
[I-D.ietf-ippm-ioam-direct-export] defines the IOAM-DEX Option-Type format as shown in Figure 1.¶
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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID | Flags |Extension-Flags| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM-Trace-Type | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flow ID (Optional) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number (Optional) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2 displays the detailed format of the Extension-Flags field that indicates presence of the optional Flow ID and/or Sequence Number fields in the IOAM-DEX header.¶
0 1 2 3 4 5 6 7 +-+-+-+-+-+-+-+-+ |F|S|U|U|U|U|U|U| +-+-+-+-+-+-+-+-+
Where elements are defined as follows:¶
[I-D.ietf-mpls-mna-usecases] recognizes the importance of IOAM in MPLS networks and lists it as one of the use cases that might be supported using MNA techniques. [I-D.ietf-mpls-mna-fwk] defines the architectural elements that compose MNA. Figure 3 displays an example of MNA elements encapsulated in an MPLS packet. The exact format will be defined in future MNA solution document(s).¶
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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ --- | Network Action Sub-Stack Indicator | U |S| U | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ NAS ~ MNA Indicators |S| ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ --- ~ In-Stack Data Block |S| | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ --- | |1| | BoS +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ --- ~ Post-Stack Data Block ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Packet Payload ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Where the enclosed elements are defined as follows:¶
In order to support direct export of the operational state and telemetry information, the IOAM-DEX blob (binary large object) Figure 1 can be placed as part of the ISD block in an MPLS label stack. In doing so, the IOAM-DEX can be used for hop-by-hop and edge-to-edge collection of the operational state and telemetry information. The length of the enclosed IOAM-DEX is determined as a function of the flag setting (Figure 2). Policies controlling the processing of the collected information and its transport are outside the scope of this document.¶
The performance considerations discussed in Section of 5 of [I-D.ietf-ippm-ioam-direct-export] are applicable here.¶
IANA is requested to assign an IOAM-DEX Network Action Indicator from its X registry.¶
Security considerations discussed in [RFC9197], [I-D.ietf-ippm-ioam-direct-export], and [I-D.ietf-mpls-mna-fwk] apply to this document.¶
TBD¶