On 9 Sep 2010, at 06:49, Mikael Abrahamsson wrote: > > In real life, ISPs consider DSCP as one thing they have the right to change > (along with TTL) in transit. I can imagine the flow label being considered > the same thing regardless of what the standard says.
The interesting thing in the academic networks through Europe and I believe Internet2 as well is that - the last time I checked - there is agreement between the NRENs (national academic ISPs) to pass DSCP values unaltered between networks. In general in those academic networks the only rewriting that may occur is at site exit routers where site policy may either determine the DSCP value a packet is marked with, or trump the DSCP value set by a user/application. I believe where policing detects excess traffic of a certain DSCP value, that traffic is dropped rather than being remarked. There are agreed semantics for DSCP values between multiple NRENs, e.g. for Premium, BE and LBE, who also agree to not alter the DSCP in transit, even though there's nothing stopping them doing so per se. I don't see why the Flow Label should be treated differently. If cooperating ISPs agree to pass it unaltered, that's fine. As the spec stands, it's hard to see how we could say otherwise. Tim -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
