Early Review of draft-ietf-idr-bgp-ls-segment-routing-ext-06
review-ietf-idr-bgp-ls-segment-routing-ext-06-opsdir-early-jaeggli-2018-05-08-00

Request Review of draft-ietf-idr-bgp-ls-segment-routing-ext
Requested rev. no specific revision (document currently at 16)
Type Early Review
Team Ops Directorate (opsdir)
Deadline 2018-05-18
Requested 2018-05-04
Requested by Susan Hares
Authors Stefano Previdi, Ketan Talaulikar, Clarence Filsfils, Hannes Gredler, Mach Chen
Draft last updated 2018-05-08
Completed reviews Opsdir Early review of -06 by Joel Jaeggli (diff)
Rtgdir Early review of -06 by Victoria Pritchard (diff)
Genart Last Call review of -14 by Roni Even (diff)
Secdir Last Call review of -14 by Paul Wouters (diff)
Assignment Reviewer Joel Jaeggli
State Completed
Review review-ietf-idr-bgp-ls-segment-routing-ext-06-opsdir-early-jaeggli-2018-05-08
Reviewed rev. 06 (document currently at 16)
Review result Has Nits
Review completed: 2018-05-08

Review
review-ietf-idr-bgp-ls-segment-routing-ext-06-opsdir-early-jaeggli-2018-05-08

I have performed a requested early review on the behalf of the operations directorate of the current draft-ietf-idr-bgp-ls-segment-routing-ext-06. Generally I think this document is good, I won't say ready, as this review is intended as an early review not a final one.

Some nits

1- 
introduction 

   This way, all BGP speakers (specifically the route-reflectors) obtain
   Link-State information from all IGP areas (and from other ASes from
   EBGP peers).

* BGP speakers are agnostic about the source of the information beyond that it was exported with certain properties from the rib of it’s neighbor.

2 - 
   An external component (e.g., a controller) then can
   collect SR information in the "northbound" direction across IGP areas
   or ASes and construct the end-to-end path (with its associated SIDs)
   that need to be applied to an incoming packet to achieve the desired
   end-to-end forwarding.

* Unqualified use of the term northbound I find generally problematic, particularly in the case of a route reflector. Previously RFC 7752 manged to use the term in the title and then never again within the text.

3- 

2.3.3.  Source Router Identifier (Source Router-ID) TLV

   The Source Router-ID TLV contains the IPv4 or IPv6 Router-ID of the
   originator of the Prefix.  For IS-IS protocol this is as defined in
   [RFC7794].  The Source Router-ID TLV may be used to carry the OSPF
   Router-ID of the prefix originator.

   The Source Router-ID TLV has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Type               |            Length             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   //                  IPv4/IPv6 Address (Router-ID)              //
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   where:

      Type: TBD, see Section 4.

      Length: 4 or 16.

      IPv4/IPv6 Address: 4 octet IPv4 address or 16 octet IPv6 address.

   The semantic of the Source Router-ID TLV is defined in [RFC7794].

* While RFC7794 Router-IDs are in fact IP addresses. OSPF Router-IDs are not even if they happen to look like them, this is particularly germain with ospfv3 but it’s worth making the distinction.

4 - 
5.1.1.  Operations

   Existing BGP and BGP-LS operational procedures apply.  No additional
   operation procedures are defined in this document.

* An informative or normative reference (probably to 7752 especially fault mangement) is probably required.