Hi Karl, On 23.07.2011 00:42, Karl Auer wrote: > Well, the obvious ones are > > a) your diagnostic may not be tracking a flow, but single packets or > groups of packets that are only part of a flow. It may even be trying to > figure out why a flow is not working.
The draft was lacking a clear problem statement so that wasn't clear to me. >> On 22 Jul 2011, at 04:59, Roland Bless wrote: >>> a) the Flow Label is part of the standard common IPv6 header, thus >>> always present and easier to process (even in the fast path) as >>> you also pointed out. > > True, but if it is in use, you have a flow you can't diagnose (at least > not by using the flow label). Bear in mind that the flow label may even Depends on what you want to diagnose. > change in transit (if I read the burbling, ever-changing discussion on > flow labels correctly, which I may well not have). That shouldn't be the case though, see Brian's reply. >>> b) Useful Flow Label support in end-systems (i.e., setting the Flow >>> Label correctly) is more likely than support for this newly >>> suggested additional option, once it would have been adopted. > > Not sure I see your point here. As soon as the flow label is being used > by end systems - correctly OR incorrectly - it can no longer be used by > diagnostic tools, or at least not if they need to modify the flow label > values. My point was referring to the case when the flow label is being used as intended, not for other purposes. >>> c) it is really unclear how you would enable the use of the proposed >>> option in end-systems on demand. In case of debugging a network >>> problem you need to enable this option later, if not too late. > > Presumably debugging tools would be able to do it. Having a debugging > tool after the fact is still better than having no tool at all. My point was that you cannot assume that every end-system has such debugging tool installed and that you can turn it on remotely. So using special end-systems as debugging tools sending these special packets out is IMHO a different setting... > My chief worry is that if you start inserting headers in a packet stream > to debug it, you are changing what it is you are debugging - for Yes. Regards, Roland -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
