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Last Call Review of draft-ietf-softwire-4rd-08

Request Review of draft-ietf-softwire-4rd
Requested revision No specific revision (document currently at 10)
Type Last Call Review
Team General Area Review Team (Gen-ART) (genart)
Deadline 2014-10-10
Requested 2014-09-27
Authors Rémi Després , Sheng Jiang , Reinaldo Penno , Yiu Lee , Gang Chen , Maoke Chen
I-D last updated 2014-10-06
Completed reviews Genart Last Call review of -08 by Christer Holmberg (diff)
Genart Last Call review of -09 by Christer Holmberg (diff)
Secdir Last Call review of -08 by Derek Atkins (diff)
Assignment Reviewer Christer Holmberg
State Completed
Review review-ietf-softwire-4rd-08-genart-lc-holmberg-2014-10-06
Reviewed revision 08 (document currently at 10)
Result Ready with Nits
Completed 2014-10-06
I am the assigned Gen-ART reviewer for this draft. For background on Gen-ART,
please see the FAQ at <>

Document:               draft-ietf-softwire-4rd-08.txt

Reviewer:                       Christer Holmberg

Review Date:                    6 October 2014

IETF LC End Date:               10 October 2014

IETF Telechat Date:             16 October 2014

Summary:                         The document is well written, and almost ready
for publication, but there are some editorial nits that I ask the authors to
address before publishing.

Major Issues: None

Minor Issues: None

Editorial nits: None


In a number of places in the document you talk about "mesh topology" and
"Hub&Spoke topology". Are those considered commonly known, or would it be
useful to have a reference?


The Abstract needs to be re-formulated. It seems to describe a problem, but
does not really say anything about the scope of the document. Normally, after
the problem statement, there would be a sentence starting with "This document
defines blah blah blah...".


The first sentence says "For deployments of residual IPv4 service via IPv6
networks,". Is there a document defining "residual IPv4 service via IPv6
networks" which you could reference?


I would suggest to split the first paragraph into smaller paragraphs. Something
like (note some minor editorial changes):

        "For deployments of residual IPv4 service via IPv6 networks, the need
        for a stateless solution, i.e. one where no per-customer state is
        needed in IPv4-IPv6 gateway nodes of the provider, is expressed in
        [I-D.ietf-softwire-stateless-4v6-motivation]. This document specifies
        such a solution, named "4rd" for IPv4 Residual Deployment.

        Using the solution, IPv4 packets are transparently tunneled across IPv6
         (reverse of 6rd [RFC5969] in which IPv6 packets are statelessly
        tunneled across IPv4 networks).

        While IPv6 headers are too long to be mapped into IPv4 headers (why 6rd
        requires encapsulation of full IPv6 packets in IPv4 packets), IPv4
        headers can be reversibly translated into IPv6 headers in such a way
        that, during IPv6 domain traversal, UDP packets having checksums and
        TCP packets are valid IPv6 packets.  IPv6-only middle boxes that
        perform deep-packet- inspection can operate on them, in particular for
        port inspection and web caches."


In section 4, the text lists a number of functions that a 4rd CE and a 4rd BR
SHOULD follow.

However, e.g. in R-2 the text says:

        "CEs and BRs MUST be configured with the following Domain parameters:"

So, is R-2 a "MUST", or a "SHOULD"?

Perhaps you in section 4 should only list the functions, and for each function
you then say whether it is SHOULD, MUST, or something else.