Support Postcard-Based Telemetry for SRv6 OAM
draft-song-6man-srv6-pbt-01

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6man                                                        H. Song, Ed.
Internet-Draft                                    Futurewei Technologies
Intended status: Standards Track                        October 14, 2019
Expires: April 16, 2020

             Support Postcard-Based Telemetry for SRv6 OAM
                      draft-song-6man-srv6-pbt-01

Abstract

   Applications such as SRv6 TE may require to collect detailed
   performance data on SR paths.  Existing in-situ OAM techniques incur
   encapsulation and header overhead issues.  This document describes a
   method based on Postcard-based Telemetry with Packet Marking for SRv6
   on-path OAM, which avoids the extra overhead for encapsulating
   telemetry-related instruction and metadata in SRv6 packets.

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.

Status of This Memo

   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
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   This Internet-Draft will expire on April 16, 2020.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Song                     Expires April 16, 2020                 [Page 1]
Internet-Draft              PBT for SRv6 OAM                October 2019

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  PBT Triggered by Marking for SRv6 . . . . . . . . . . . . . .   3
     2.1.  Data Template . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Postcard Correlation  . . . . . . . . . . . . . . . . . .   4
     2.3.  Operational Considerations  . . . . . . . . . . . . . . .   4
   3.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   6.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .   5
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   5
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   The ability to collect the on-path data about SRv6 packets at each
   segment is important for SRv6 OAM, especially for monitoring the
   application-aware services.  Some SR-TE algorithms need to acquire
   realtime flow forwarding performance on each path.  The In-situ OAM
   (IOAM) [I-D.ietf-ippm-ioam-data] trace option can be used for such
   purpose.  However, SRv6's SRH can be large due to the long segment
   list.  The IOAM trace option introduces significant additional
   overhead to the SRv6 packets with its instruction and data trace.
   The large header overhead complicates the packet processing and may
   exceed the forwarding hardware's header processing capability.

   The extra IOAM trace option header also brings encapsulation
   challenges as documented in [I-D.li-6man-ipv6-sfc-ifit].  Here we
   only restate a subtle issue about the IOAM scope: if IOAM header is
   encapsulated as another IPv6 extension header, the juxtaposition of
   IOAM and SRH makes it ambiguous to determine the scope and coverage
   of IOAM: it is unclear if the IOAM is applied to the entire
   forwarding path or just to the segment nodes.  In reality, either
   case can find its application.

Song                     Expires April 16, 2020                 [Page 2]
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