Reviewer: Erik Kline Review result: On the Right Track I am the assigned Gen-ART reviewer for this draft. The General Area Review Team (Gen-ART) reviews all IETF documents being processed by the IESG for the IETF Chair. Please treat these comments just like any other last call comments. For more information, please see the FAQ at <https://trac.ietf.org/trac/gen/wiki/GenArtfaq>. Document: draft-ietf-bfd-vxlan-07 Reviewer: Erik Kline Review Date: 2019-05-27 IETF LC End Date: 2019-05-31 IESG Telechat date: Not scheduled for a telechat Summary: If my understanding is correct (which it may well not be), this document places restrictions on the inner Ethernet and IP layer deployment that previously may not have been present. My reading if this document is that the outer IP header and the inner IP header have the same VTEP src and dst IPs. The outer and inner Ethernet headers have the same source MAC and may have the same dst MAC. Is this correct? If so, this would mean that the VTEP's MAC address (or the special dest MAC) cannot be used within the VXLAN network (or at least not on the same host. Similarly, it appears that the VTEP's IP addresses are no longer free to be used within the encapsulated VXLAN VNI. Do I understand this correctly? Was this always the case? If there is a document defining restrictions that VTEPs place on the inner VXLAN segment, that might be good to reference. Failing that, I think I would like to see some discussion of alternatives that were rejected with reasons behind their rejection. One possible solution might be to use "impossible" Ethernet addresses and "impossible" IP addresses in the inner packet. For example, a source IP address of all ones or all zeros would be very unlikely to ever be a valid IP packet. I'm not 100% sure, but I suspect that a source MAC of all ones would also never really be treated as valid. Clever use of multicast IP and Ethernet addresses in the source fields might also be sufficient to render the inner packet "invalid" in the sense that it would never collide with legitimate traffic. If I have misread this document, or VTEPs are already placing constraints on the inner VXLAN environment similar to those above, then this review should instead be treated as "Ready with Nits". Major issues: Only my concern/misunderstanding described above. Minor issues: None. Nits/editorial comments: * The document generally does a really good job of Expanding Acronyms At First Use (EAAFU) -- very much appreciated. In section 1 though, NVE is used without accompanying expansion, I think. * There is no 4.2 so maybe sections 4 and 4.1 could just be section 4.
