Hi Brian, > -----Original Message----- > From: ipv6-boun...@ietf.org [mailto:ipv6-boun...@ietf.org] On Behalf Of > Brian E Carpenter > Sent: Wednesday, June 26, 2013 6:14 PM > To: 6man > Subject: draft-bonica-6man-frag-deprecate > > Cutting to the chase, and assuming that the next version > will have more analysis and observational evidence, I'm thinking > something like the following: > > 3. Recommendation > > This memo deprecates IPv6 fragmentation and the IPv6 fragment > header. > Application and transport layer protocols SHOULD support effective > PMTU discovery [RFC4821], since ICMP-based PMTU discovery [RFC1981] > is unreliable. Any application or transport layer protocol that > cannot support effective PMTU discovery MUST NOT in any > circumstances > send IPv6 packets that exceed the IPv6 minimum MTU of 1280 bytes.
But, if those 1280 packets go into a tunnel they become (1280 + HLEN) and are vulnerable to loss. This is even before we start talking about tunnels-within-tunnels. It should therefore be well established by now that tunnels over IPv6 MUST be capable of some form of frag/reass. > IPv6 stacks and forwarding nodes SHOULD continue to support inbound > fragmented IPv6 packets as specified in [RFC2460]. However, this > requirement exceeds the capability of some types of forwarding node > such as firewalls and load balancers. Therefore implementers and > operators need to be aware that on many paths through the Internet, > IPv6 fragmentation will fail. Legacy applications and transport > layer > protocols that do not conform to the previous paragraph can expect > connectivity failures as a result. Without some form of frag/reass, tunnels over IPv6 will black-hole. If IPv6 frag/reass is off the table, then we simply need something else. That something else is SEAL. Thanks - Fred fred.l.temp...@boeing.com > -------------------------------------------------------------------- > IETF IPv6 working group mailing list > ipv6@ietf.org > Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 > -------------------------------------------------------------------- -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
