Here's my review of the DNA I-D: One global concern: I'm concerned that DNA may not be applicable to all networks. There seems to be some implicit assumptions about the networks that must be true - and these assumptions are not necessarily going to be true on all of the networks that DNA seems to be targeting. In cases where DNA cannot automatically determine that the host is in such a network, it should be possible to turn DNA off manually and resort to old-style ND.
Specific concerns: 1) What track is this Internet Draft on - Standards? 2) I'm concerned about two major deployment scenarios, each of which is likely to affect millions of subscribers off of the same aggregation router: a) The router offers no PIO in the RA - thus, no prefix is available. This is currently being discussed as a possible way to prevent poorly implemented host stacks which ignore the M and A bits in the RA from doing SLAAC and force them to do DHCPv6 or not get online. Unfortunately, this case breaks DNA as there is no prefix available to identify the link. The "at least one router on a link MUST be configured with one prefix" is a limitation of DNA. b) The prefix for a neighborhood is the same for all access points in the neighborhood. This can happen if home users are off of bridge modems and they are all bridging the same prefix (which is defined on a bundle interface of the aggregation router. This is done to conserve address space and simplify network configuration by MSO's. Unfortunately, this means that DNA will detect every AP in the neighborhood as the same link. Even worse, when DNA causes the node not to do DHCPv6 again, the aggregation router which understands which home corresponds to which addresses, causes source verify to reject traffic from the roaming laptop. What should happen is that the node should try to do DHCPv6 again when it roams even when the prefix is the same - this doesn't work in DNA. 3) The routers being able to advertise a prefix list as complete assumes that they know about all the routers on the link. However, one of the routers could be silent for a while, and a router may assume that it knows all of the prefixes on the link but may be wrong. 4) "Any future non-prefix link identifier MUST be 128 bits long." - Why? 5) Are the MAX_RTR_SOLICITATIONS and RTR_SOLICITATION_INTERVAL chosen to scale up to 100,000 hosts off of an aggregation router? What if multiple interfaces startup at the same time? Will there be an RS storm and will the token bucket rate limiting cause RS's to be dropped as described in the security considerations case? I suspect that this case may be even more common than you might suspect... You may have to adjust UNICAST_RA_INTERVAL and MAX_UNICAST_RA_BURST to deal with interface bringups on the aggregation router. 6) "The router MUST pick the smallest prefix of all the prefixes configured on the routers on the link as the common prefix." What if there are 2 smallest prefixes? 7) "an absence of that overlap can be used to infer link change" in 5.1.8 is repeated again in 5.1.9, and 5.1.9.1 - please eliminate redundancy. 8) In 5.2.6.1, one of the IF statements is missing - "{ Link change has occurred. RETURN; }" but no IF, and occurred is spelled wrong. 9) Why do you need to infer upstream reachability? - Wes -----Original Message----- From: Hemant Singh (shemant) Sent: Friday, August 31, 2007 11:40 AM To: Suresh Krishnan; ipv6@ietf.org; [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: RE: [Fwd: WGLC for draft-ietf-dna-protocol-06.txt] Suresh, I have few minor comments on this I-D. Wes Beebee will send more detailed comments sometime later today. He has reviewed the I-D. 1. While reading the Abstract, I'd like to know what is the maximum delay DNAv6 is ready to accept in a response from router? 2. Stateful has been deprecated for use. We should call it DHCPv6. Therefore section 5.2.7 should change statefully to DHCPv6. Hemant -----Original Message----- From: Suresh Krishnan [mailto:[EMAIL PROTECTED] Sent: Wednesday, July 11, 2007 11:29 AM To: ipv6@ietf.org; [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: [Fwd: WGLC for draft-ietf-dna-protocol-06.txt] Hi Folks, We would like to hear your comments on this document as well. This document is a significant update to ipv6 neighbor discovery and we would like some more eyeballs. Please spare some time from your busy schedule to give it a look. Thanks Suresh -------- Original Message -------- Subject: WGLC for draft-ietf-dna-protocol-06.txt Date: Wed, 04 Jul 2007 15:47:24 -0400 From: Suresh Krishnan <[EMAIL PROTECTED]> To: Dna <[EMAIL PROTECTED]> CC: Greg Daley <[EMAIL PROTECTED]>, Jari Arkko <[EMAIL PROTECTED]> This mail starts a 2 week working group Last Call for comments for the following dna working group document draft-ietf-dna-protocol-06.txt to be sent to the IESG for consideration as a Standards Track RFC. Please review the document carefully, and send your feedback to the list. Please also indicate whether or not you believe that this document is ready to go to the IESG. The last call will end on 2007/07/18. Cheers Suresh & Greg -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 -------------------------------------------------------------------- -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 -------------------------------------------------------------------- -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------