personally, I would prefer to see it *mutable*, and undefined. Given that there are many host implementations out there, I could imagine difficulties getting any specific specification (such as a hash) widely deployed in a finite amount of time. However, if a network could use it to identify an egress or the path to an egress (or, using multiple values per egress, sets of traffic headed to an egress) in a scalable fashion, it might allow for load sharing among what would today be non-sharable MPLS LSPs.
On Apr 22, 2010, at 1:23 PM, Manfredi, Albert E wrote: >> -----Original Message----- >> From: ipv6-boun...@ietf.org [mailto:ipv6-boun...@ietf.org] On >> Behalf Of Shane Amante > >> c) Declare the flow-label is _immutable_ and must be set by >> all hosts and must only contain a 3- or 5-tuple hash of the >> appropriate IPv6 headers. Further use cases for the >> flow-label would be restricted. IMHO, this would be by far >> the easiest from an implementation and operational >> point-of-view, however this is unlikely to appeal to >> proponents of domain-specific special-uses of flow-labels, >> unfortunately. > > Count me in. In following this thread, I've come to believe that this is the > best course of action. And it keeps the flow label immutable, as originally > prescribed. > >> Therefore, if a legitimate use of flow-labels has not been >> found in the last 15 years of IPv6 development, it's time to >> move on and use the flow-label for something useful and >> practical in production networks, (i.e.: a hash of the 3- or >> 5-tuple of L3 + L4 headers for LAG + ECMP load-balancing). > > Indeed. This becomes doable easily in IPv6, no matter the extension headers. > What better purpose could there be for this field? And it's certainly NOT a > stretch to think that the traditional 5-tuple was, in fact, used to define > what some might call a "flow." > > Bert > -------------------------------------------------------------------- > IETF IPv6 working group mailing list > ipv6@ietf.org > Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 > -------------------------------------------------------------------- http://www.ipinc.net/IPv4.GIF -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
