Subject: Re: [mpls] [Technical Errata Reported] RFC3107 (4582)

From: Alexander Okonnikov <[email-masked]>
Date: Sat, 9 Jan 2016 02:12:01 +0300

Using terms "NLRI" and "Prefix" interchangeably is a root of confusion. 
I saw good example of how clarification could be done to distinguish 
them. Follow example is from RFC 7432, section 7.1:

"... For the purpose of BGP route key processing, only the Ethernet 
Segment Identifier and the Ethernet Tag ID are considered to be part of 
the prefix in the NLRI. The MPLS Label field is to be treated as a route 
attribute as opposed to being part of the route. ..."

Indeed, in SAFI 4 NLRI label is attribute of prefix rather than part of 
prefix itself. This was implicitly assumed in RFC 3107, but was not 
stated explicitly.

Agree with deprecation of capability type 4, because a) we have 
add-paths mechanism now and b) this capability could pose some problems 
and thus is unreliable, for example, when two routes have the same label 
value.

Using 0x800000 though is not in line with rule of label stack encoding, 
but perhaps only solution for backward compatibility. May be it makes 
sense to deprecate encoding BoS (due to deprecation of multiple routes).

Thank you.