My only point would be, I don't think that this proposed use of flow label stretches the definition of "flow" all that much, as I have been interpreting "flow" over the years. I've always thought of "flow" as IETF-speak for "circuit," as sacriligious as that might sound to some folk. So anything that a provider might once have done by specifying an ATM VPI/VCI over an ATM network, that same provider could do with the combination of IP addresses and flow label in an IPv6 core. At least, in principle.
A tunnel does not seem to be an unusual application of the concept? In IPv4, this task required MPLS. With an IPv6 core network, the FL could be used instead, as others have alluded to recently in the 6man list. Bert > -----Original Message----- > From: ipv6-boun...@ietf.org [mailto:ipv6-boun...@ietf.org] On > Behalf Of Brian E Carpenter > Sent: Saturday, September 25, 2010 3:54 PM > To: Yiu L. Lee > Cc: ipv6@ietf.org; Frank Brockners (fbrockne) > Subject: Re: Question for Flow Label > > The flow label has always been defined as immutable, but for > examples that break the standard, see draft-hu-flow-label-cases. > > For the rest I agree with Joel. > > Regards > Brian Carpenter > > On 2010-09-25 14:40, Yiu L. Lee wrote: > > Hi Joel, > > > > Sorry for my ignorance. Can you explain to me what is > mutable flow label or > > pint me to a reference I can read? You are right, this > usage wasn't intended > > to substitute for transport protocol and port numbers in > ECMP and LAG. But I > > guess FL could be used for other purposes other than ECMP > and LAG as long as > > it wasn't caused any conflict. > > > > Thanks, > > Yiu > > > > > > On 9/24/10 10:25 PM, "Joel M. Halpern" <j...@joelhalpern.com> wrote: > > > >> It is quite a stretch to claim that all traffic > originating from (or in > >> the other direction destined to) a single customer constitute a > >> meaningful "flow". However, because RFC 3697 was > carefully written to > >> be vague about this, it would be difficult to prove that > it is incompatible. > >> > >> I would note that this usage of flow label would be > inconsistent with > >> mutable flow labels, and would be inconsistent with the > desire to use > >> flow label as a meaningful subsitute for transport > protocol and port > >> numbers in ECMP and LAG logic. Whether either of those > two incompatible > >> desires will themselves be standardized is extremely > unclear at this > >> point, although there seems to be significant resistance > to having flow > >> labels be mutable. > >> > >> Yours, > >> Joel M. Halpern > >> > >> On 9/24/2010 10:14 PM, Yiu L. Lee wrote: > >>> Hi gents, > >>> > >>> We have a design question of Flow Label. During the v6 > transition, some DSL > >>> providers may want to create an IPv4-in-IPv6 tunnel from > the BRAS to the > >>> AFTR to continue to provider v4 access over a v6 core > network. To identify a > >>> CPE behind the BRAS, we propose to use the Flow Label. > Each CPE will be > >>> assigned with a Flow Label. This Flow Label represents a > flow of all encap > >>> v4-in-v6 traffic behind a CPE. The Flow Label will be > applied on the v6 > >>> address of the BRAS. v6 hosts behind the CPE will have > their v6 addresses > >>> and be most probably from a different v6 prefix, so their > flow labels won't > >>> be affected. > >>> > >>> You can find the details in: > >>> http://tools.ietf.org/html/draft-zhou-softwire-ds-lite-p2p-02 > >>> > >>> Our question is: "Is this usage compatible to RFC 3697?" > We posted this > >>> question to Softwires and we were told to also ask 6man for input. > >>> > >>> Thanks, > >>> Yiu > >>> > >>> > -------------------------------------------------------------------- > >>> 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 > > -------------------------------------------------------------------- > > > -------------------------------------------------------------------- > 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 --------------------------------------------------------------------
