[c-nsp] SR (was BGP Signalled VPLS)

[Saku Ytti]

On (2013-08-09 23:10 +0300), Tassos Chatzithomaoglou wrote:

> Just wondering, is it possible to somehow create a segment path from an SDN controller, using more labels than the ones supported in an intermediate hop?
> Will the SDN controller be able to take into account such per-node limitations?

I think it would be quite contrived example if SDN would workaround the
limitations of long explicit paths.
But theoretically you could imagine that if you have PE1-P1-P2..-P99-PE2,
where you need explicit path, PE1 could avoid imposing full path, if in SDN
(or otherwise) you cause PE1 to push magic label N which P1 will swap to
number of other labels (you could think of it as pseudo adjacency between
P1 and P99)

> Although not an expert on this area, it amazes/worries me that although IETF docs are in very early stage, vendor EFT code already exists.

It seems quite typical? tag-switching was ran in networks long before MPLS
RFCs were ready.
Two implementations must pre-date Internet Standard by definition.

-- 
  ++ytti