high CPU on cisco 2921 router

[vithoba.batgiri]

frequent high cpu on cisco 2921 router

[Joseph W. Doherty]

From stats, it appears your router just might be busy routing packets.  What's the average traffic volume that transits this router?

[vithoba.batgiri]

Around 30 to 35mbps traffic on wan link...

[Leo Laohoo]

What is the size/bandwidth of the WAN link?

[Joseph W. Doherty]

Well that's somewhat in line with what Cisco recommends a 2921 for, i.e. up to 50 Mbps WAN links.

See attachment for details.

[MHM Cisco World]

this Router have neighbor that use static route toward this router ?

[Georg Pauwen]

Hello,

post the full running configuration of your router just in case, maybe we can spot something...

[sp2720401]

IP input... It could be a bunch of things. route cache, route cache same interface, PBR, CEF... 

Without configurations for routing decisions you can't determine what configuration or bug might be a problem. 

[Joseph W. Doherty]

"IP input..."

Well, from OP, IP input shows under 1% CPU for 5 sec, 1 minute and 5 minute.  So, from that, difficult to say it's a "classical" IP Input issue.

However, I have seen some functions, such as IP fragmentation, push (way) up interrupt CPU (at least in later IOS versions).  I.e. it's certainly possible, traffic and its interaction with the router's configuration, is causing higher than expected CPU usage.  (NB: from my prior post's attachment, would expect a 2921 to still have some CPU headroom at the OPs later posting of noted 30 to 35 Mbps average traffic load.)

[MHM Cisco World]

Ip input & arp, i have one thing

If you had config 

Ip static route x.x.x.x x.x.x.x gex/x

This make router send arp for each packet and this is wrong config,

You must config next-hop ip instead of oultlet interface.