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New Member

Very high processing

I have a 3640 with 3 bridge groups configured over separate frame-relay subinterfaces.A bridge group is dedicated to only 1 interface.I noticed that when customers configured with bridge groups are active and getting much traffic,the processing of the router increases and this appears in the IP INPUT process.I am using cef and fast switching.For serial interfaces without BVI interfaces,a part of the output of the command "show interface stats" is almostly as follows :


Switching path Pkts In Chars In

Processor 5830 11402

Route cache 36051 49785

Total 11881 31187

Which shows that the cache is used in forwarding many packets while for bvi interfaces,the output is as follows:

Switching path Pkts In Chars In Pkts Out Chars Out

Processor 19410142 399036124

Route cache 0 0

Total 19410142 399036124

Which shows that the cache is not used at all for BVIs.And I think this may be the reason of high processing.does any one have any suggestion to solve this problem.I think I can disable cef to force the interface to use fast switching.Does anyone has any suggestion

New Member

Re: Very high processing

cef uses a lot of resources. disable cef and see



Re: Very high processing

The most likely problem is that the packets aren't being CEF switched through the BVI interface. I seem to remember something about BVI interfaces being CEF switched at some point, but I could be wrong. I'd cruise through the feature navigator and see if I could find out if there is some point where BVI interfaces are CEF switched.

Turning CEF off isn't going to help anything, I would think. If CEF can't switch a packet, it will punt the packet to fast before the packet is tossed to ip input (the process switching path) anyway, if the image has unicast fast switching in it (some newer images don't). Turning CEF off isn't going to help the fast switching path switch anything, or it shouldn't.

Don't turn CEF off, try and figure out why CEF isn't switching these packets. I don't know of any places in normal operation (not software defects) that CEF would cause your CPU utilization in ip input to go up.