Re: [Pce] draft-hsd-pce-sr-p2mp-policy wiki comments and action.

[Dhruv Dhody <[e-mail]>]

Hi,

Speaking as a WG member...

Let's continue the discussion on considering the replication segment
as an LSP v/s PCECC operation.

I just wanted to quickly recap -

- We have stateful operations for RSVP-TE: RFC 8231, RFC 8281
- We then introduced SR with a minimal extension of new PST and a new
SR-ERO subobject: RFC 8664
- We supported P2MP stateful operations for RSVP-TE with RBNF change
in PCEP messages: RFC 8623

We have always tried our best to maintain consistency between RSVP-TE
and SR in PCEP.

Now, if one considers the Replication segment as an LSP operation,
IMHO it needs to be built on RFC 8623 P2MP LSP operations. The current
approach does not build on RFC 8623 instead uses the multi-path
technique (related to ECMP in P2P [1]). This would deviate from RFC
8623 significantly.

On the other hand, considering the replication segment as a PCECC/CCI
operation gives you more leeway to choose an encoding with a new CCI
Object type for the replication segment and it could be independent of
RFC 8623.

I *still* feel PCECC makes more sense at the higher level too (because
of the additional instruction to the leaves and coordination
required). Even if one disagrees with that and considers it an LSP
operation, it then needs to build on RFC 8623. The current "mashup"
approach (i.e. it is an LSP operation but does not follow P2MP LSP
encoding) does not work well in maintaining consistency within our
extensions.

Thanks!
Dhruv (as a WG member)
[1] https://datatracker.ietf.org/doc/draft-koldychev-pce-multipath/