On Wed, Apr 04, 2001 at 11:01:41AM -0700, Kireeti Kompella wrote:
> Hi Robert,
>
> > The only use of exp-null today would be to pass the QoS info in the EXP
> > bits to the tailend as otherwise this info is lost at PHP and tail has
> > no way of knowing how to schedule the packets (of course assuming that
> > QoS in IP header is different then the one in EXP field - something what
> > we call QoS transparency :).
>
> Ah, so you don't want to touch the IP QoS/ToS bits. Okay, got it.
>
> Somewhere in this conversation, there was mention that ciscos had
> trouble with label 0/label 3 (and ditto junipers). I can speak for
> the latter; can you comment on the former? If there is no issue with
> using label 0, should Juniper simply go back to using label 0 always?
> I'd rather not be putting any more knobs than are really necessary ...
I think it's usefull to, on a per interface basis, be able to choose
between Explicit and Implicit null.
So a knob would be nice to have.
> What if the label stack has depth > 1? PHP in that case? Bit yucky,
> but doable.
rfc 3032 section 2.1 state
i. A value of 0 represents the "IPv4 Explicit NULL Label".
This label value is only legal at the bottom of the label
stack. It indicates that the label stack must be popped,
and the forwarding of the packet must then be based on the
IPv4 header.
So yes, for label stacks with a depth > 1 you must use 3 and not 0
/Jesper
-- Jesper Skriver, jesper(at)skriver(dot)dk - CCIE #5456 Work: Network manager @ AS3292 (Tele Danmark DataNetworks) Private: FreeBSD committer @ AS2109 (A much smaller network ;-)One Unix to rule them all, One Resolver to find them, One IP to bring them all and in the zone to bind them.
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