On 11/02/2012 04:52 PM, Nick Hilliard wrote: > E.g. a fully loaded 6509 with 384 ports would take ~3000 queries every > several minutes to perform full port diagnostic polling, and you'd want to > be doing this every couple of seconds to cause serious CPU impact. Are you > doing something like full DFZ or MAC table polling?
I bet you're close toward the end there. My guess is he's carrying a large BGP feed and querying the ipRouteTable. The caveat below is for IOS 12.4(20)T but equivalent issues surely exist for CatOS: http://www.cisco.com/en/US/docs/ios/12_4t/release/notes/124TCAVS3.html#wp2057950 The killer in this case is not the SNMP traffic or anything resulting directly from it, but the CPU overhead from constantly re-sorting the ipRouteTable since that's generated from the FIB when CEF is enabled. Workaround is to disable CEF (heh) or configure a MIB view that excludes the ipRouteTable. This one bites an OpenNMS support customer a few times a year -- happened again just today, in fact, at a shop that just enabled topology discovery. > Also, you may want to consider moving away from CatOS, as it's now > basically abandonware (or at least will formally be in Jan 2013), and > hasn't even seen maintenance updates in the last 4 years. What you said :) -jeff
