Le 14 avr. 2010 à 23:59, Mark Smith a écrit : > Hi Brian and Sheng, > > On Wed, 14 Apr 2010 16:48:25 +1200 > Brian E Carpenter <[email protected]> wrote: > >> Hi, >> >> This is completely revised from the proposal we presented >> in Anaheim. This version allows locally defined use of >> the flow label in a simpler way, as the discussion suggested. >> It's still quite a dense read, but we believe that if this was >> adopted, it would open the way to actually using the flow label. >> > > I've had a read through it, although not a comprehensive one, which > I'll endeavour to do in the next day or so. > > I'm wondering about this change for a couple of reasons: > > -- > 2. If this is done, all packets in a given flow MUST be given the > same flow label value. A flow is defined in this case as all > packets with the same source and destination IPv6 addresses and > port numbers and the same transport protocol number, i.e., the > same final Next Header value [RFC2460]. This rule constrains the > definition of a flow in RFC 3697 for the specific case that a > router sets the flow label. However, it does not constrain the > bits of the flow label in any particular way. > -- > > Firstly, if the IPv6 packets are fragments, the transport layer header > may not be available.
> I think that would mean that although these > packets fragments are part of a flow, they wouldn't have their flow > label changed. Strictly speaking, it doesn't prevent routers from changing flow labels, but it does impose that new values depend only on 3-tuples (source address, destination address, last Next Header). In practice this limits significantly benefits to be expected from allowing routers to modify flow labels. A very good point indeed. More comments to come in the next answer to Brian. RD -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
