Rate limit a subnet with shaping as opposed to policy

Answered Question
Mar 16th, 2010
My research has lead me to 2 areas for  configuration of shaping. Apply shaping on class-map and/or the policy-map??
Objective = limit subnet to 256K at all times.
Access-list 1 permit <subnet>
Class-map 256k_limit
Match access-group 1
bandwidth  256000 (not sure if this is required/relevant) 
shape  peak 256000
policy-map  256K_choke
class  256k_limit
(perhaps shaping should be applied here??)
int  xyz
service-policy output 256K_choke (FYI data to be choked comes in on interface  abc and out on xyz)

I understand from my previous discussion/port that shaping will provide users on subnet xyz with better performance as buffering would be used should bandwidth increase above 256K.

This is my previous solution with policy

/* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;}

access-list 1 permit <subnet>

class-map 256_limit

match access-group 1


policy-map subn_rate_limit

class 256_limit

police 256000 conform-action transmit  exceed-action drop  violate-action drop

interface g0/0

service-policy output subn_rate_limit

Am on on the right track?

I have this problem too.
0 votes
Correct Answer by Giuseppe Larosa about 6 years 10 months ago

Hello John,

you are on the right track

Class based shaping can be applied outbound and the change is in the policy-map configuration where the action is changed from police .... to shape.

see command reference for shape command in policy map context


Hope to help


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