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Circuit Congestion

Nobody's Hero
Valued Contributor

Circuit Congestion

I have been having a problem with a cisco 7200 router. Using NNM, watching the "Frame Relay Circuit-congestion" Is it normal to see spikes near 100% congestion from time to time? Spike may only reach 100 for about 30-45 seconds then it drops to 2%. This action repeats on and off every few minutes. The spikes are blue and green which are the serial DLCI in and out.
Any opinions appreciated. Just wondering if I should see zero congestion. Both ends are running 100/full dup.

10x
RPM
UNIX IS GOOD
4 REPLIES
doug mielke
Respected Contributor

Re: Circuit Congestion

Just a shot, since no one else has chimmed in.

Since frame relay is not near as fast as the rest of the network, it would seem that congestion could be expected whenever the frame ports had a messege, acting as a bottleneck. Depending on size of message, congestiuon could last a while.
Steven E. Protter
Exalted Contributor

Re: Circuit Congestion

This type of congestion could be due to a wiring issue. Try replacing the patch cables one at a time and see if the problem recurs.

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Steven E Protter
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Tim Sanko
Trusted Contributor

Re: Circuit Congestion

I have seen the same kind of thing when looking at a network on the East Coast.

It turned out that the whole issue was solved by purchase of newer faster frame relay box with more cache(ram) ...

It may be that there is a memory log that you may want to look at.

Tim
Tim Sanko
Trusted Contributor

Re: Circuit Congestion

Have you put a sniffer before the frame relay box to see if this is memory moving to accommodate large blocks, or if this is legitimate traffic.

Sometimes when some idiot makes an MTU of 30K (I know the default is 1500) and then routs stuff to a frame relay box, you can see serious puking.

This can happen when there is a custom IP apps and a flexible configuration. (Saw this at a company in NJ... running ATMs for banks...)

Tim

Tim