[nsp] cef process-switching (was: ip verify unicast not logging in ACL)

Oliver Boehmer (oboehmer) oboehmer at cisco.com
Wed Nov 12 10:19:11 EST 2003

> > CEF switching can occur in both the interrupt as well as the process
> > path (at least in recent IOS releases like 12.0S/12.2/12.3/etc.),
> > the latter is called "CEF process path". This was mainly added to
> > enable tag/mpls primitives (push/pop/swap) also in the process path
> > (ex: "debug mpls packet" causes the mpls pkts to be
> > "process-cef-switched", "debug ip packet" also prints a "cef
> > process switched" or similar in the debug).
> awww, i've been wondering once why tagsw/mpls/vrf still works even if
> the interfaces have 'no ip route-cache cef'...

It shouldn't work if you disable CEF on the ingress interface as you'll
disable CEF, not the interrupt path (unless you'd also configure "no ip

> > So in summary: A CEF-switched pkt is not necessarily nterrupt
> > switched.. 
> > 
> now speaking of cef-process - does all of this apply to nbar and other
> features, too?

I don't have a complete list which features do and don't work with CEF,
but the list has been getting shorter and shorter.. can't give a quick
answer on this..


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