[c-nsp] 3750 with high CPU

[Rubens Kuhl Jr.]

> > >  The current template is "desktop default" template.
> > >  The selected template optimizes the resources in
> > >  the switch to support this level of features for
> > >  8 routed interfaces and 1024 VLANs.
> >
> > Giving this 3750 high cpu usage problem some thought, I noticed the "8
> > routed interfaces" limit. To the 3750, what does exactly constitute a
> > routed interface ? Anything that shows up on "show ip interface brief"
> > with an IP address,
>
> Yes.
>
> However, the other numbers from "show sdm prefer" are more interesting.
> The limit we usually have problems with is "number of indirect routes",
> which are normal non-connected IP routes.

Number of indirect routes seemed to be less than the limit, as opposed
to routed interfaces which we clearly exceed 8.

I tried wandering around "show platform" commands, with no success in
knowing which ip interfaces were being hardware routed and which are
punted, or how to prioritize some interfaces over others (as Cat 6k
had at some point so one could tell which ACLs it should compile to
TCAM). Something interesting was:

#show platform ip unicast counts
# of HL3U fibs 1406
# of HL3U adjs 28
# of HL3U mpaths 31
# of HL3U covering-fibs 0
# of HL3U fibs with adj failures 0
Fibs of Prefix length 0, with TCAM fails: 0
(more prefix lengths with 0 fails)
Fibs of Prefix length 24, with TCAM fails: 2076
Fibs of Prefix length 29, with TCAM fails: 501

So although there are less indirect routes (1406) than the template
limits (2k), lots of prefixes show "TCAM fails". "show ip cef summary"
results on the same 1.4k prefix count.




Rubens