[pim] PIM light (draft-ietf-pim-light) and PORT (RFC6559)

[Toerless Eckert <[e-mail]>]

Repeating here on the list what i said on the mike @IETF115, PIM, also Cc' BIER 
WG as hopefully a beneficiary of this work (draft-ietf-pim-light).

We really had a lot of reliability problems under reconvergence of
PIM with large amounts of stte which are well applicable as a problem
to the target use-cases of PIM light, especially with BIER which will
allow up to support a lot of state much better. Thousands of PIM joins
that under routing reconvergence events have to be buffered as a huge
burst and/or vendor specific pacing that reduces convergence performance.

We solved these problems with mLDP and BGP signaling instead of PIM,
and we also then solved them for PIM via PIM over TCP (RFC6559).

I would really like to see:

a) The authors/WG check if/what if any issues threre would be to
   use PORT with pIM light. I hope/expect none, but if there are,
   lets discuss.

b) Include a requirement that PIM light MUST default to use PORT
   and MAY support datagram PIM encapsulation.

Aka: i really see no reason to continue to use datagram encap with PIM light,
so the "MAY" is really just for unforeseen cases.

Cheers
    Toerless