Subject: [Idr] Warren Kumari's No Objection on draft-ietf-idr-bgp-prefix-sid-14: (with COMMENT)

From: Warren Kumari <[email-masked]>
Date: Wed, 07 Feb 2018 14:33:43 -0800

Warren Kumari has entered the following ballot position for
draft-ietf-idr-bgp-prefix-sid-14: No Objection

When responding, please keep the subject line intact and reply to all
email addresses included in the To and CC lines. (Feel free to cut this
introductory paragraph, however.)

Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html
for more information about IESG DISCUSS and COMMENT positions.

The document, along with other ballot positions, can be found here:
https://datatracker.ietf.org/doc/draft-ietf-idr-bgp-prefix-sid/

----------------------------------------------------------------------
COMMENT:
----------------------------------------------------------------------

Thanks for Acee for addressing my DISCUSS - cleared.

Major(ish) issue:
Section 5.  Advertising BGP Prefix-SID Attribute
   "The BGP Prefix-SID attribute MAY be attached to labeled BGP prefixes
   (IPv4/IPv6) [RFC8277] or to IPv6 unicast prefixes [RFC4760].  In
   order to prevent distribution of the BGP Prefix-SID attribute beyond
   its intended scope of applicability, attribute filtering SHOULD be
   deployed."
Thank you for including this -- however, as I'm sure you know, the state of BGP
filtering in the wild is, er, poor. Can you please provide some additional
guidance? For example, could you include an appendix with examples? Or simply a
bit more text on determining the scope of applicability? Apologies if I missed
this, but should this by default be filtered on eBGP sessions? The included
text is a great start, but some more (so people don't miss it and shoot
themselves in the foot would be much appreciated.

Nits:
Section 1:
" the SID consists of a label while when SR is applied to the IPv6 dataplane
the SID consists of an IPv6 address." I think that "of a label, while" would
make this much more readable. It took me a few tries without it.

Section 4:
" A BGP speaker receiving a BGP Prefix-SID attribute from an EBGP
   neighbor residing outside the boundaries of the SR domain, MUST
   discard the attribute unless it is configured to accept the attribute
   from the EBGP neighbor."
Spurious comma between domain and MUST (yeah, I want a comma above, I don't
want one here, no pleasing some people. They are nits :-))