[PWE3] AD comments on draft-ietf-pwe3-dynamic-ms-pw

[Stewart Bryant <[e-mail]>]

I am about to put this into IETF LC.

Please consider the following as LC comments.

- Stewart

Network Working Group                                 Luca Martini (Ed.)
Internet Draft                                        Cisco Systems Inc.
Expires: April 2014
Intended status: Standards Track                     Matthew Bocci (Ed.)
Updates: 6073                                         Florin Balus (Ed.)
                                                           Alcatel-Lucent

                                                          October 8, 2013


              Dynamic Placement of Multi-Segment Pseudowires


                   draft-ietf-pwe3-dynamic-ms-pw-19.txt

SB> it updates the length value of the PW Switching Point PE Sub-TLV Type 0x06 to 14.
SB> It is confusing to talk about the "length value" of a TLV. I think you
SB> mean "length"





2.1. Changes to Existing PW Signaling


    This document also updates the length value of the PW Switching Point
    PE Sub-TLV Type 0x06 to 14.

SB> Same comment as above



4.2. LDP Signaling


    The complete definitions of the content of the SENDER_TSPEC objects
    are found in [TSPEC] section 3.1.

SB> TSPEC is actually RFC2210 isn't it?
SB> If so that would be a much better reference identifier



4.2.1. Equal Cost Multi Path (ECMP) in PW Routing

    A next hop selection for a specific PW may find a match with a PW
    route that has multiple next hops associated with it. Multiple next
    hops may be either configured explicitly as static routes or may be
    learned through BGP routing procedures. Implementations at and S-PE
SB> s/and/an/

    or T-PE MAY use selection algorithms, such as CRC32 on the FEC TLV,
    for load balancing of PWs across multiple next-hops. The details of
    such selection algorithms are outside the scope of this document.

SB> Presumable FAT is another option?

  4.2.2. Active/Passive T-PE Election Procedure


    The determination of which T-PE assumes the active role SHOULD be
    done as follows: the Source Attachment Individual Identifier (SAII)
    and TAII are compared as unsigned integers, if the SAII is bigger
    then the T-PE assumes the active role.

SB> This does not look quite precise enough. You need to specify which bytes
SB> and the bit order. What you say is technically correct
SB> but isn't it clearer to say that the T-PE with the larger
SB> SAII is active?
SB> I do not see (pointer to) a definition of SAII or TAII in this draft



6. Operations and Maintenance (OAM)

    In this case, the following TLV type (0x06) MUST be used
    in place of type 0x01 in the PW switching point TLV:

SB> This is "PW Switching Point PE sub-TLV" in RFC6073
SB>

SB> Are there any interoperability issues with the change of length to
SB> 14, i.e. is there any length 12 code in the wild?