On 2011-02-22 19:24, Pekka Savola wrote: > On Tue, 22 Feb 2011, Brian E Carpenter wrote: >> Well, I object to drawing anyone's attention to the Appendix of >> 2460, which is explicitly not part of the standard. And I think >> that the main text in 2460 is underspecified, whereas RFC 3697 >> has proved to be plain confusing. And we don't yet have clear >> consenus on 3697bis. Does all this belong in a requirements list? > > Which part of 3697 that is relevant to this document is plain > confusing? Those that pertain to this spec are IMHO in Section 3 which > seems clear enough to me (copied below).
But this text will be completely different in 3697bis. I really wouldn't want to set people off coding according to something that we already know will change. Brian > > 3. Flow Labeling Requirements > > To enable Flow Label based classification, source nodes SHOULD assign > each unrelated transport connection and application data stream to a > new flow. The source node MAY also take part in flow state > establishment methods that result in assigning certain packets to > specific flows. A source node which does not assign traffic to flows > MUST set the Flow Label to zero. > > To enable applications and transport protocols to define what packets > constitute a flow, the source node MUST provide means for the > applications and transport protocols to specify the Flow Label values > to be used with their flows. The use of the means to specify Flow > Label values is subject to appropriate privileges (see section 5.1). > The source node SHOULD be able to select unused Flow Label values for > flows not requesting a specific value to be used. > > A source node MUST ensure that it does not unintentionally reuse Flow > Label values it is currently using or has recently used when creating > new flows. Flow Label values previously used with a specific pair of > source and destination addresses MUST NOT be assigned to new flows > with the same address pair within 120 seconds of the termination of > the previous flow. The source node SHOULD provide the means for the > applications and transport protocols to specify quarantine periods > longer than the default 120 seconds for individual flows. > > To avoid accidental Flow Label value reuse, the source node SHOULD > select new Flow Label values in a well-defined sequence (e.g., > sequential or pseudo-random) and use an initial value that avoids > reuse of recently used Flow Label values each time the system > restarts. The initial value SHOULD be derived from a previous value > stored in non-volatile memory, or in the absence of such history, a > randomly generated initial value using techniques that produce good > randomness properties [RND] SHOULD be used. > -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
