Rate-limits Cisco Router

Apr 20, 2005 3 Replies
C

Hi all



I have a cisco router which uses rate-limits to control traffic inbound and outbound of each interface. The router is a 3600 and here is an example of one of the interfaces:



interface Serial2/2 bandwidth 2048 ip address 10.x.x.x 255.x.x.x ip verify unicast reverse-path no ip redirects no ip proxy-arp rate-limit input 1024000 25000 25000 conform-action transmit exceed-action drop rate-limit output 1024000 25000 25000 conform-action transmit exceed-action drop ip summary-address eigrp x 0.0.0.0 0.0.0.0 5 no ip mroute-cache ntp broadcast no cdp enable



Can someone please explain how the rate limits work?



Many thanks



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J

Hi, I wonder if this helps at all?

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Basically on your example here

rate-limit input 1024000 25000 25000 conform-action transmit exceed-action drop

this is a looking at data coming into the interface and limiting it to 1 megabit/s,

"conform-action transmit" means, "transmit anything that is below 1 megabit/s"

and this bit "exceed-action drop" means, "drop anything that is above 1 megabit/s"

The other two numbers are burst-normal - Normal burst size, in bytes. The minimum value is bps divided by 2000." burst-max which means - Excess burst size, in bytes

Though I must admit I don't really understand what those burst-normal and burst-max actually mean. Maybe someone else can explain.

Regards

Paul

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C

Thanks Paul,

Can anyone else explain the difference between Normal and Excess burst rates and how they work?? I have read the Cisco literature but looking for an explanation in simple terms!

Also will the Bandwidth command have any effect on the traffic allowed through the interface?

cheers

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J

No. But it does affect metrics under OSPF which might make the route more or less desirable.

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