QoS CAR Rate Limiting by Access List on Cisco

Previous posting are CAR rate policies:

• All IP traffic
• MAC address

You can set another CAR rate policies with IP Access List, both standard and extended. Matching to IP access list is more processor intensive than based on other.

The following example shows how CAR can be used to limit the rate by application to ensure capacity for other traffic.

#### Define application in access-list

IOS(config)#
 access-list 101 permit tcp any any eq ftp
end

#### Set CAR rate policies for ftp 4 Mbps, other 1 Mbps & Apply to interface

IOS(config-if)#
interface FastEthernet1/1
 description To-Router
 ip address 192.168.100.1 255.255.255.0
 rate-limit output access-group 101 4096000 512000 512000 conform-action set-prec-transmit 5 exceed-action set-prec-transmit 0
 rate-limit output 1024000 128000 128000 conform-action set-prec-transmit 5 exceed-action drop

#### Verify CAR

IOS#show interfaces FastEthernet1/1 rate-limit
FastEthernet1/1 To-Router
  Output
    matches: access-group 101
      params:  4096000 bps, 512000 limit, 512000 extended limit
      conformed 0 packets, 0 bytes; action: set-prec-transmit 5
      exceeded 0 packets, 0 bytes; action: set-prec-transmit 0
      last packet: 11650560ms ago, current burst: 0 bytes
      last cleared 00:00:15 ago, conformed 0 bps, exceeded 0 bps
    matches: all traffic
      params:  1024000 bps, 128000 limit, 128000 extended limit
      conformed 3 packets, 222 bytes; action: set-prec-transmit 5
      exceeded 0 packets, 0 bytes; action: drop
      last packet: 1832ms ago, current burst: 0 bytes
      last cleared 00:00:12 ago, conformed 0 bps, exceeded 0 bps