on supporting IOAM in IPv6

[Haoyu Song <[e-mail]>]

Hi all,

We will present this draft in the lighting talk session of IPPM WG meeting in IETF108
https://datatracker.ietf.org/doc/draft-song-ippm-ioam-ipv6-support/

Since there is usually no time for any discussion for the short talk in the meeting, we'd like to start this email discussion thread, also involving the relevant 6man WG, to solicit suggestions and comments.
Below is a quick summary:

The draft is related to another WG draft https://datatracker.ietf.org/doc/draft-ietf-ippm-ioam-ipv6-options/ in which the IOAM trace option is proposed to be carried as an IPv6 HBH option.

However, using HBH, the mandatory first extension header,  to carry the large and potentially variable size IOAM trace option can be very challenging for implementations,
especially when some other extension headers, such as SRv6 RH, must be accessed.

This draft discuss several alternatives to avoid or mitigate the problem, including:

  1.  Separate the header part and data part of the IOAM trace option, and move the data part to a later extension header while keeping the header part in HBH
  2.  Using the IOAM DEX option instead to avoid carrying data in packet
  3.  Using the segment IOAM trace method to ensure the IOAM data will be stripped off and exported at some specific nodes (e.g., SRv6 segments),  so the IOAM option header can remain short and constant at these nodes.
     *   Flavor 1: Fixed segment size encoded in IOAM option header
     *   Flavor 2: Configurable by network controller

Please see more detailed description in the draft. The draft only covers the IOAM-related methods, although other methods are also possible.

Please let us know what you think. Thank you very much!

Best regards,
Haoyu