In-situ OAM IPv6 Options
draft-ietf-ippm-ioam-ipv6-options-02

Abstract

In-situ Operations, Administration, and Maintenance (IOAM) records operational and telemetry information in the packet while the packet traverses a path between two points in the network. This document outlines how IOAM data fields are encapsulated in IPv6.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

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This Internet-Draft will expire on January 14, 2021.

Copyright Notice

Copyright (c) 2020 IETF Trust and the persons identified as the document authors. All rights reserved.

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Table of Contents

• 1. Introduction
• 2. Conventions
• 2.1. Requirements Language
• 2.2. Abbreviations
• 3. In-situ OAM Metadata Transport in IPv6
• 4. Security Considerations
• 5. IANA Considerations
• 6. Acknowledgements
• 7. References
• 7.1. Normative References
• 7.2. Informative References
• Authors' Addresses

1. Introduction

In-situ Operations, Administration, and Maintenance (IOAM) records operational and telemetry information in the packet while the packet traverses a path between two points in the network. This document outlines how IOAM data fields are encapsulated in the IPv6 [RFC8200].

2. Conventions

2.1. Requirements Language

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.

2.2. Abbreviations

Abbreviations used in this document:

OAM:

Operations, Administration, and Maintenance

IOAM:

In-situ OAM

POT:

Proof of Transit

E2E:

Edge-to-Edge

3. In-situ OAM Metadata Transport in IPv6

In-situ OAM in IPv6 is used to enhance diagnostics of IPv6 networks. It complements other mechanisms proposed to enhance diagnostics of IPv6 networks, such as the IPv6 Performance and Diagnostic Metrics Destination Option described in [RFC8250].

IOAM data fields are encapsulated in “option data” fields of two types of extension headers in IPv6 packets - either Hop-by-Hop Options header or Destination options header. The selection of a particular extension header type depends on IOAM usage, as described in section 4 of [I-D.ietf-ippm-ioam-data]. Multiple options with the same Option Type MAY appear in the same Hop-by-Hop Options or Destination Options header, with varying content.

In order for IOAM to work in IPv6 networks, IOAM MUST be explicitly enabled per interface on every node within the IOAM domain. Unless a particular interface is explicitly enabled (i.e. explicitly configured) for IOAM, a router MUST drop packets which contain extension headers carrying IOAM data-fields. This is the default behavior and is independent of whether the Hop-by-Hop options or Destination options are used to encode the IOAM data. This ensures that IOAM data does not unintentionally get forwarded outside the IOAM domain.

An IPv6 packet carrying IOAM data in an Extension header can have other extension headers, compliant with [RFC8200].

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  Option Type  |  Opt Data Len |   Reserved    |   IOAM Type   |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
|                                                               |  |
.                                                               .  I
.                                                               .  O
.                                                               .  A
.                                                               .  M
.                                                               .  .
.                          Option Data                          .  O
.                                                               .  P
.                                                               .  T
.                                                               .  I
.                                                               .  O
.                                                               .  N
|                                                               |  |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+

IPv6 Hop-by-Hop and Destination Option format for carrying in-situ OAM data fields:

Option Type:

8-bit option type identifier as defined inSection 5.

Opt Data Len:

8-bit unsigned integer. Length of this option, in octets, not including the first 2 octets.

Reserved:

8-bit field MUST be set to zero upon transmission and ignored upon reception.

IOAM Type:

8-bit field as defined in section 7.2 in [I-D.ietf-ippm-ioam-data].

Option Data:

Variable-length field. Option-Type-specific data.

In-situ OAM Options are inserted as Option data as follows:[I-D.ietf-ippm-ioam-data] are aligned at a multiple-of-4 offset from the start of the Hop-by-Hop and Destination Options header. In addition, to maintain IPv6 extension header 8-octet alignment and avoid the need to add or remove padding at every hop, the Trace-Type for Incremental Trace Option in IPv6 MUST be selected such that the IOAM node data length is a multiple of 8-octets.

1. Pre-allocated Trace Option: The in-situ OAM Preallocated Trace option defined in [I-D.ietf-ippm-ioam-data] is represented as an IPv6 option in Hop-by-Hop extension header:

   Option Type:

   001xxxxx 8-bit identifier of the IOAM type of option. xxxxx=TBD.

   IOAM Type:

   IOAM Pre-allocated Trace Option Type.

2. Incremental Trace Option: The in-situ OAM Incremental Trace option defined in [I-D.ietf-ippm-ioam-data] is represented as an IPv6 option in Hop-by-Hop extension header:

   Option Type:

   001xxxxx 8-bit identifier of the IOAM type of option. xxxxx=TBD.

   IOAM Type:

   IOAM Incremental Trace Option Type.

3. Proof of Transit Option: The in-situ OAM POT option defined in [I-D.ietf-ippm-ioam-data] is represented as an IPv6 option in Hop-by-Hop extension header:

   Option Type:

   001xxxxx 8-bit identifier of the IOAM type of option. xxxxx=TBD.

   IOAM Type:

   IOAM POT Option Type.

4. Edge to Edge Option: The in-situ OAM E2E option defined in [I-D.ietf-ippm-ioam-data] is represented as an IPv6 option in Destination extension header:

   Option Type:

   000xxxxx 8-bit identifier of the IOAM type of option. xxxxx=TBD.

   IOAM Type:

   IOAM E2E Option Type.

All the in-situ OAM IPv6 options defined here have alignment requirements. Specifically, they all require 4n alignment. This ensures that fields specified in

An outline of how the options defined here can be enabled and used in an IPv6 network is provided in [I-D.ioametal-ippm-6man-ioam-ipv6-deployment].

4. Security Considerations

This document describes the encapsulation of IOAM data fields in IPv6. Security considerations of the specific IOAM data fields for each case (i.e., Trace, Proof of Transit, and E2E) are described and defined in [I-D.ietf-ippm-ioam-data].

As this document describes new options for IPv6, these are similar to the security considerations of [RFC8200] and the new weakness documented in [RFC8250].

5. IANA Considerations

This draft requests the following IPv6 Option Type assignments from the Destination Options and Hop-by-Hop Options sub-registry of Internet Protocol Version 6 (IPv6) Parameters.

http://www.iana.org/assignments/ipv6-parameters/ipv6- parameters.xhtml#ipv6-parameters-2

   Hex Value    Binary Value      Description           Reference
                act chg rest
   ----------------------------------------------------------------
   TBD_1_0      00   0  TBD_1     IOAM                  [This draft]
   TBD_1_1      00   1  TBD_1     IOAM                  [This draft]

6. Acknowledgements

The authors would like to thank Tom Herbert, Eric Vyncke, Nalini Elkins, Srihari Raghavan, Ranganathan T S, Karthik Babu Harichandra Babu, Akshaya Nadahalli, Stefano Previdi, Hemant Singh, Erik Nordmark, LJ Wobker, Mark Smith, Andrew Yourtchenko and Justin Iurman for the comments and advice. For the IPv6 encapsulation, this document leverages concepts described in [I-D.kitamura-ipv6-record-route]. The authors would like to acknowledge the work done by the author Hiroshi Kitamura and people involved in writing it.

7. References

7.1. Normative References

7.2. Informative References

Authors' Addresses