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

[Rodney Dunn]

For the record.  I filed a ddts to investigate if
this can be done. 

The ddts # is:

CSCef49249
Need ability to disable dCEF on a per VIP basis

Work is under way to determine if it's possible to do it.

Rodney

 

On Fri, Aug 13, 2004 at 08:02:24AM -0400, Rodney Dunn wrote:
> 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