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Abnormal input rate on interface

I have a 3600 series router and 3500 series catalyst switch. VLANs were created by assigning subinterfaces in router. Since two days many of my interfaces are showing abnormal input rate which is above the resricted level[restriction made by rate limit input command]. This causes the customer link as down. Please reply to my problem.


MDU-SWITCH#sh int fa0/5

FastEthernet0/5 is up, line protocol is up

30 second input rate 623000 bits/sec, 998 packets/sec

30 second output rate 0 bits/sec, 0 packets/sec

699414 packets input, 54566586 bytes

Received 250 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 0 multicast 0 input packets with dribble condition detected

4041 packets output, 950965 bytes, 0 underruns

0 output errors, 0 collisions, 2 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

The limit i configured in router was

rate-limit input 128000 130000 132000 conform-action transmit exceed-action dro


traffic-shape rate 256000 7936 7936 1000


Re: Abnormal input rate on interface


If i understand the layout of 3600 router with 3500 s/w, the cust is hooked on to 3500 s/w on a switchport , rt?

if this is the case, den the cust is uploading a lot of traffic which is reflecting in the input rate.this inturn is exceeding the effective CIR configured for the cust.the link could get bogged and slow down as its not conforming to the traffic rate.this means the excess rate is also overridden, check this with the show interfaces () rate-limit command.chk for the exceeded/ conformed packets.

I guess the cust needs an incr in b/w.

wht u can do to test tht is to incr the actual input rate by another 384 k and chk if still u get the exceeded counts and can also chk by havin mrtg to chk on duration of traffic rise.

if rest is fine..then it means there is a excessive non confirming traffic broadcast from the cust end .

Pls reply and rate the post.

Community Member

Re: Abnormal input rate on interface

Thanks for the reply. That traffic is exceeding only for a particular period. Also the customer is not uploading any valid data that time. But some broadcast it might be. Now my query is how to control that broadcast from customer which is esceeding the rate limit input rate and making customer link slower.

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