Rate-limited services are becoming popular among dedicated server and co-location customers for a variety of reasons. Some want a burstable service but wish to be protected from large, unexpected overage charges. Others are purchasing "unmetered" service at increments such as 20Mbps. Small network operators may not want to give their customers a full 100Mbps burstable port to reduce their exposure to overage bills or prevent a single customer from being able to saturate a 100Mbps switch or router uplink port.

Whatever your reason for deploying a configuration that rate-limits customer traffic, the below example applies to many Cisco IOS platforms. It will allow up to 5Mbps of traffic from the customer on port FastEthernet0/1, with a burst margin of 26KByte per 1Mbps. This example is not a complete configuration for any platform, and includes only statements relavent to the task.

mls qos
!
class-map match-any ip-any
  match access-group 1
!
policy-map 5Mbps
  class ip-any

    police 5000000 130000 exceed-action drop
!
interface FastEthernet0/1
 description "customer 123 port 1"
 no switchport
 ip address 172.16.0.1 255.255.255.252
 no ip proxy-arp
 service-policy input 5Mbps
 duplex full
 speed 100
!
interface GigabitEthernet0/1
 description "uplink to core switch"
 switchport trunk encapsulation dot1q
 switchport mode trunk
 flowcontrol send off
!
access-list 1 permit any