On Mar 9, 2011, at 00:35 MST, Igor Gashinsky wrote: > On Wed, 9 Mar 2011, Randy Bush wrote: > > :: a real use for the diffserv bits! why not flowlabel in 6? it's been > :: looking for a use for a decade. > > Honestly, we figured flowlabel might actually find a use before all the > values of diffserv will :) In all seriousness, we are starting to set the > spec for v6 l3dsr now, so, if you care, and believe that flowlabel would > be a better field to "hijack" (or have a suggestion for another, better > way then same DSCP methodology that we used for ipv4), we welcome input..
:-/ Please don't abuse the flow-label this way, otherwise your proposal could get added to the "graveyard of IPv6 flow-label proposals" draft: http://tools.ietf.org/html/draft-hu-flow-label-cases-03#section-3 There has been *a lot* of discussion in the 6man WG recently to (finally) define the flow-label to be: a) be stateless; and, b) potentially be useful as an input-key, when used in conjunction with {src_ip, dst_ip}, for fine-grained load-balancing over LAG & ECMP paths, (instead of the traditional IPv6 header 5-tuple). One example where this might be useful is within Layer-2 switches, at IXP's or other parts of the network, where you'd really like them to only have to look at the 3-tuple: {src_ip, dst_ip + flow-label} as input-keys for LAG load-balancing, since they are at a fixed location in the IPv6 header. The other, longer-term win of this approach is that hosts can be free to define, or re-define, new IPv6 Extension Headers and you won't have to worry about Core routers/switches needing to dig into those Ext. headers (or, past them) to find useful input-keys for load-balancing over LAG & ECMP paths. Take a look at the following drafts and comment on the 6man WG mailing list if you have questions or concerns: IPv6 Flow Label Specification -- proposed revisions to the most current (& confusing) flow-label RFC: http://tools.ietf.org/html/draft-ietf-6man-flow-3697bis-01 Using the IPv6 flow label for equal cost multipath routing and link aggregation in tunnels http://tools.ietf.org/html/draft-ietf-6man-flow-ecmp-01 Rationale for update to the IPv6 flow label specification http://tools.ietf.org/html/draft-ietf-6man-flow-update-03 -shane
