Jon Marshall Tue, 07/08/2008 - 02:03
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policy-map Shape-all-20

class class-default

shape average 20000000

int fa0/1

service-policy output Shape-all-20

where fa0/1 is the interface you want to do the shaping on.

Shaping is generally better than strict rate-limiting as instead of just dropping packets it smooths out the bursts of traffic.


richard.gosling Tue, 07/08/2008 - 02:10
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Thats clear so what would this statment produce:

rate-limit input 20000000 30000000 40000000 conform-action transmit exceed-action drop

rate-limit output 20000000 30000000 40000000 conform-action transmit exceed-action drop

cheers Richard

cisco_lad2004 Tue, 07/08/2008 - 02:29
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U have 2 options:

1-Shaping as per Jon's post, which will buffer and gives users a better experience.

2-strict policing is as you mentionned. personally, I prefer below command ( in a policy map).

police BW bps BURST byte conform-action transmit exceed-action drop

Though shaping is better as it does not drop when it can buffer. But it is CPU taxing.

Policing is stricter, but not so hard on CPU.



richard.gosling Tue, 07/08/2008 - 02:47
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How do I configure this?

I just trying to get my head round this

I need a policy-map also a class map and bind it to the interface right ?

cisco_lad2004 Tue, 07/08/2008 - 02:58
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policy-map LIMIT

class class-default

police 5.5 mbps 400 kbyte conform-action transmit exceed-action drop

#under interface#

service-policy output LIMIT

richard.gosling Tue, 07/08/2008 - 03:11
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ok so when I enter police 200000000 (normal burst bytes)

what does normal burst bytes do?

cisco_lad2004 Tue, 07/08/2008 - 03:20
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use 1/4 of that, then divide further by 8 to get the value in Byte..or simply divide by 32.

its just a guidelines I use sometimes.

richard.gosling Tue, 07/08/2008 - 03:29
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Does not like this to much

(config-if)#service-policy output


Configuration failed!

Warning: Assigning a policy map to the output side of an interface not supported

cisco_lad2004 Tue, 07/08/2008 - 03:34
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depends on platform, and maybe also interface type.

are u on a 35XX and Interface VLAN ?


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