[c-nsp] disabling dCEF per VIP on 7500?

Gert Doering gert at greenie.muc.de
Fri Aug 13 02:54:11 EDT 2004


Hi,

On Thu, Aug 12, 2004 at 07:39:29PM -0400, Rodney Dunn wrote:
> No way to do it that I know of.
> If I remember correctly it's because of the way
> the FIB is downloaded to the VIP's.  It's not
> unicast to each VIP from what I recall.

Well - the router itself *can* do it (if one of the VIP runs out of 
memory, dCEF will be disabled for that VIP).  This is just something I
don't like to have in production, a router that will "eventually at
some point" auto-change its setup...

> And honestly, I would never run a 75xx that way.
> It makes the switching paths too complicated and
> open to bugs.

Actually the switching paths are "that way" anyway - on the low-speed
interfaces, the box does "ip accounting out", so punting to CEF happens
all the time anyway.

> If you go to any of the fancy QOS features we
> only support them in full dCEF mode because of
> multiple reasons: scalability, simplicity in the
> swithing vector, etc.

Now those would be on the high-speed interfaces anyway... :-) (but no need
for it right now).

gert

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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de


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