[c-nsp] BGP Signalled VPLS

[Saku Ytti]

On (2013-08-09 18:24 +0300), Nitzan Tzelniker wrote:

> regarding SR one thing that I thing is a problem with it is the number of
> labels you can push on the smaller hardware platform (ASR901/Juniper ACX)
> if you want to do a strict path you will have to push a lot of labels and
> in these platforms you are limited.

I wonder what the actual HW limitations are, ASR901 I think is CSCO
internal, ACX is BCM.

Is the documented mpls label stack depth limitation how many levels of
abstraction you have (lookup VPN label in VRF table, then lookup IGP label
in LDP/IGP, two lookups, two levels of abstraction, essentially two
lookups). 
If this is the limit, then in explicit route case this limit might be
exceeded by returning more than 1 label as rewrite information of single
lookup, in explicit route, you'd know whole stack after one lookup, it
would just return more data.

IPv4 tunnel lookup returning 20B rewrite information might not be any
different to lookup returning 5*4B labels.
Or lookup result being IPv6 header might be analogous to returning 10
labels.

I however don't have any data, this is purely conjecture.
-- 
  ++ytti