[Pce] Comments on draft-ietf-pce-segment-routing-08

[Cyril Margaria <[e-mail]>]

Dear PCE'ers

I reviewed the document and I have the following comments/questions:

1)       The document implies that the PCC has to /MUST do IP address to
SID conversion, I  think that it would allow a more simpler PCC if that
capability is optional  and negotiated with additional error codes to
indicate that the NAI SR-EROs are not supported.

2)       One aspect of the SR-ERO processing is that,  when building the
label stack, the PCC should have enough information to decide on the
outgoing link (this can be provided by the PCE). It will be good if the
document state could spell out this part of the procedure and indicates any
specific SR-ERO procedure. For instance one solution could be  that the PCE
may use IP address or Adjacency SID to indicate the outgoing link.

3)       Taking the outgoing link selection into account, the Maximum Stack
Depth (MSD) calculation may be not trivial: for instance if the first hop
is a local Adjacency-SID, then the label will not be stacked, but it will
if the first hop is a Prefix SID it may be counted (non-adjacent node or
adjacent node without PHP) but it may not be counted (adjacent node, with
PHP). I think the draft should clarify it.

Thanks,

Cyril