[c-nsp] BGP scanner taking up CPU

[Joris de Mooij]

Hi all,

We have a 6506 with Sup720-MSFC2 running IOS 12.2(18)SXD5. This router
holds the entire internet BGP table. Now we are suspecting the BGP
scanner process for causing temporary high CPU loads. Because this
process runs with a high priority, exec commands, pings and snmp seem no
to get through anymore. When using the vty exec, output seem to stall
for 1 to 3 seconds at least every minute.

Now we have already turned off any unnecessary commands using CPU (also
no logging console). 

Now there is a command to tune how long a single process can claim the
cpu. This timer can be tuned with the process-max-time command. The
process-max-time is default 200 ms (and this is also the max). It can be
tuned down 20 ms. 

Can anyone tell me if lowering this value could have a positive effect
on the CPU usage of the BGP scanner process?

One other thing that may be beneficial is to use next-hop
address-tracking (NHT). Available in IOS 12.3(14)T and up. I am not sure
if this feature is supported on 65xx sup720 (software advisor claims it
is not) and upgrading this router has a big impact. Anyone ever used
this feature on a 65xx sup720 and know of its impact on the BGP scanner?

Grtz,
Joris