Hello,

I have been selected as the Routing Directorate reviewer for this draft. The Routing Directorate seeks to review all routing or routing-related drafts as they pass through IETF last call and IESG review, and sometimes on special request. The purpose of the review is to provide assistance to the Routing ADs. For more information about the Routing Directorate, please see ​http://trac.tools.ietf.org/area/rtg/trac/wiki/RtgDir

Although these comments are primarily for the use of the Routing ADs, it would be helpful if you could consider them along with any other IETF Last Call comments that you receive, and strive to resolve them through discussion or by updating the draft.

Document: draft-ietf-softwire-mesh-multicast-22.txt
 Reviewer: Nicolai Leymann
 Review Date: 09/06/18
 IETF LC End Date: date-if-known
 Intended Status: Standards Track

Summary:
I have some minor concerns about this document that I think should be resolved before publication.

Comments:
The draft in general is in good shape. The problem description is clear as well as the solution to the problem. Nevertheless it took almost 8 year in order to go from first draft to last call and I wonder if there are any implementations available (or if there are alternatives with a broader deployment).

Major Issues:
"No major issues found."

Minor Issues:
- The relation to RFC8114 is a bit unclear.
The draft references several times RFC8114 which describes a solution for delivering IPv4 Multicast over an IPv6 Multicast network. Draft-ietf-softwire-mesh-multicast describes also a solution for IPv4-over-IPv6 Multicast. From a functional point of view the result is the same and there are several similarities. I think the differences should be made more clear and therefore also the motivation for a solution based on draft- ietf-softwire-mesh-multicast.
- The draft also mentions MPLS as protocol for the I-IP but the solution focusses at IPv6 as I-IP. What role does MPLS play in the context of IPv6 as I-IP (if packets are MPLS encapsulated in the inner IP network)? This should also be clarified.

Nits:
Section 3:
“
   o I-IP (Internal IP): This refers to IP address family that is
   supported by the core network.  In this document, the I-IP is IPv6.

   o E-IP (External IP): This refers to the IP address family that is
   supported by the client network(s) attached to the I-IP transit core.
   In this document, the I-IP is IPv6.
“
I think the last sentence should read as “In this document, the E-IP is IPv4”.

Regards

Nic