I am the assigned Gen-ART reviewer for this draft. For background on Gen-ART, please see the FAQ at < http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>. Please resolve these comments along with any other Last Call comments you may receive. Document: draft-ietf-softwire-dslite-deployment-06 Reviewer: David L. Black Review Date: October 15, 2012 IETF LC End Date: October 16, 2012 IESG Telechat Date: October 25, 2012 Summary: This draft is on the right track but has open issues, described in the review. This is a generally well-written draft that expands considerably on the brief deployment considerations for DS-Lite in Appendix A of RFC 6333. The draft is clear and reasonably well-written, and a significant improvement on that RFC 6333 Appendix, although an understanding of RFC 6333 is necessary to understand this draft, which seems completely reasonable. The B4 and AFTR acronyms are clever - kudos to whomever came up with those. I found five open issues, all of which are minor. Minor Issues: [1] Ironically, the first issue is that something should be said about the relationship of this draft to Appendix A of RFC 6333. It probably suffices to say that this draft expands on the material in that Appendix, as I see no need to specify that this draft updates RFC 6333 solely to change non-normative material in an Appendix. [2] The MTU increase technique in Section 2.2 is a "may", which is consistent with Section 5.3 of RFC 6333. OTOH, Section 2.2 of this draft should also discuss the AFTR resource exhaustion concern that described in Section 6.3 of RFC 6333, as that is a potential operational reason for an ISP to increase MTU size (e.g., if customer sourcing of large IPv4 packets is not sufficiently rare). [3] Section 2.7 refers to "the AFTR's internal interface". There may be two internal interfaces, the physical IPv6 interface (outer header) and the tunnel's IPv4 interface (inner header). The text should be clarified to indicate which interface is involved - it appears that the AFTR's physical IPv6 interface is intended in this section. [4] Section 2.7 cites RFC 6333 for use of DHCPv6 with DS-Lite. RFC 6334 should be cited - either in addition to or instead of RFC 6333. [5] Section 2.8 discusses IPv4 accounting at the AFTR, but notes that "the AFTR does not have detailed customer identity information." Does that create a theft of service possibility? If so, that possibility should be mentioned as a security consideration. Also, Section 2.8 ought to be expanded with a sentence or two explaining why the AFTR does not have that identity information, and in particular to explain whether and why it is unreasonable in some or all cases to expect that customer identity information be provided to the AFTR as part of provisioning each customer's softwire. Nits: Section 2.3 on MTU Considerations could usefully mention MTU discovery techniques, as possibilities for customer IPv4 traffic to adapt to a smaller IPv4 MTU. If this is done, it would be useful to mention RFC 4821 in addition to the mention of RFC 1191 in RFC 6333. Section 2.4 should define "lawful intercept". It would be helpful to cite a reference for this concept if something appropriate can be found. Section 2.5: - Are one or both types of logging recommended? - Last paragraph on p.4, "timestamped log" is not a good verb phrase. "maintain a timestamped log of" would be a better replacement. - Last paragraph in section, where is the batch file sent? In Section 2.7, I'm having a hard time understanding which traffic is intended to be subject to the Outgoing Policies and the Incoming Policies. Expanding each of those two bullets to explain what traffic is subject to each class of policies would help. Section 3.2.2.2 uses 192.0.0.2/32 as an example IP address for the B4. That section should also cross-reference Section 5.7 on RFC 6333 on IP address assignment to B4s, as other IP addresses may be used. idnits 2.12.13 found a tiny nit - draft-ietf-pcp-base is now at version 28. Thanks, --David ---------------------------------------------------- David L. Black, Distinguished Engineer EMC Corporation, 176 South St., Hopkinton, MA  01748 +1 (508) 293-7953             FAX: +1 (508) 293-7786 david.black at emc.com        Mobile: +1 (978) 394-7754 ----------------------------------------------------