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

[Rodney Dunn]

On Fri, Aug 13, 2004 at 08:54:11AM +0200, Gert Doering wrote:
> 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...

I never said it *can't* do it.  What I said was that there
is not way internally today that I know of for the FIB to
be manually disabled to a particular VIP.  I'm checking with
DE on an idea to see if we can possibly do it but no promises
at this point.

> 
> > 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.

We recommend netflow which is distributed.

> 
> > 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).

Usually the QOS is needed on the low speed interfaces so those would
be the VIPs that you would want doing dCEF.

Let me talk with DE some about a couple of ideas and get back to ya.

> 
> gert
> 
> -- 
> USENET is *not* the non-clickable part of WWW!
>                                                            //www.muc.de/~gert/
> Gert Doering - Munich, Germany                             gert at greenie.muc.de
> fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de