[c-nsp] Determining software switched FIB entries

[Euan Galloway]

On Thu, Jan 10, 2008 at 10:12:23AM -0700, Clinton Work wrote:
> 
> The following should do the trick.  
> show mls cef | inc punt

IIRC you are just meant to get the normal "0.0.0.0/0 drop" entry changed to 
"0.0.0.0/0 punt" to get everything that hasn't made it into the TCAM to be 
punted to the MSFC for processing.  Or at least that's what TAC said.

This didn't help/work when we had a 0.0.0.0/0 route BEFORE the drop one.

> Chris Griffin wrote:
> > Is there a way to determine *which* entries are software switched when a 
> > Sup720 exceeds FIB TCAM?  In testing I see general warnings from various 
> > show commands that exceptions have occurred, but having a way to figure 
> > out if a given fib entry was software switched would be helpful.

For a given prefix it's easy enough to compare "show ip cef" to "show mls cef".
Other than that, I had to dump the entire outputs and script comparing them.

With the outputs of show ip cef and show mls cef each in a file I did this 
to compare number of prefixes...

for i in `seq 1 24`
 do
 FIB=`fgrep "/$i " $FIBFILE | wc -l`
 RIB=`fgrep "/$i " $RIBFILE \
 | fgrep -v "127.0.0.0/8" \
 | fgrep -v "224.0.0.0/4" \
 | wc -l`
 echo "Number of /$i in RIB: $RIB FIB: $FIB"
done

Easy enough to find which from $RIBFILE are not in $FIBFILE and 
"clear ip route" if you find ones your trying to force back into the TCAM.

-- 
Euan Galloway