To configure traffic policing based on a percentage of bandwidth available on an interface, use the police command in policy-map class configuration mode. To remove traffic policing from the configuration, use the no form of this command.

police cir percent percent [bc conform-burst-in-msec] [pir percent percent]

[be peak-burst-in-msec]

no police cir percent percent [bc conform-burst-in-msec] [pir percent percent]

[be peak-burst-in-msec]

cir - Committed information rate. Indicates that the cir will be used for policing traffic.

Bc - (Optional) Conform burst (bc) size used by the first token bucket for policing traffic.

Be - Optional) Peak burst (be) size used by the second token bucket for policing traffic.

For further information click this link.

http://www.cisco.com/en/US/docs/ios/12_0s/feature/guide/12spbtbp.html#wp1046933