Cisco IE 4000, Software Configuration Manual

Page: 592 / 1066

588
Configuring QoS
Understanding QoS
Switch(config)#
policer aggregate agg1 cir 23000 bc 10000 conform-action set-dscp-transmit af31
set-cos-transmit 3 exceed-action set-dscp-transmit af11 set-cos-transmit 1
Switch(config)# class-map video-provider-1
Switch(config-cmap)#
match access-group 1
Switch(config-cmap)# exit
Switch(config)# class-map video-provider-2
Switch(config-cmap)#
match access-group 2
Switch(config-cmap)# exit
Switch(config)# class-map match-any customer1-provider-100
Switch(config-cmap)#
match vlan 100
Switch(config-cmap)# exit
Switch(config)# class-map match-any customer1-provider-200
Switch(config-cmap)#
match vlan 200
Switch(config-cmap)# exit
Switch(config)# policy-map child-policy-1
Switch(config-pmap)#
class video-provider-1
Switch(config-pmap-c)# set dscp af41
Switch(config-pmap-c)# exit
Switch(config-pmap)#
class class-default
Switch(config-pmap-c)# police aggregate agg1
Switch(config-pmap-c)# exit
Switch(config)#
policy-map child-policy-2
Switch(config-pmap)# class video-provider-2
Switch(config-pmap-c)# set dscp cs4
Switch(config-pmap-c)#
exit
Switch(config-pmap)# class class-default
Switch(config-pmap-c)# police aggregate agg1
Switch(config-pmap-c)#
exit
Switch(config)#
policy-map customer-1-ingress
Switch(config-pmap)# class customer1-provider-100
Switch(config-pmap-c)#
service-policy child-policy-1
Switch(config-pmap-c)#
exit
Switch(config-pmap)# class customer1-provider-200
Switch(config-pmap-c)
# service-policy child-policy-2
Switch(config-pmap-c)#
exit
Switch(config)# interface fastethernet0/1
Switch(config-if)#
switchport mode trunk
Switch(config-if)#
service-policy input customer-1-ingress
Switch(config-pmap-c)# exit
Unconditional Priority Policing
Priority policing applies only to output policy maps. You can use the priority policy-map class configuration command
in an output policy map to designate a low-latency path, or class-based priority queuing, for a specific traffic class. With
strict priority queuing, the packets in the priority queue are scheduled and sent until the queue is empty, at the expense
of other queues. Excessive use of high-priority queuing can create congestion for lower priority traffic.
To eliminate this congestion, you can use the priority with police feature (priority policing) to reduce the bandwidth used
by the priority queue and allocate traffic rates on other queues. Priority with police is the only form of policing supported
in output policy maps.
Note: You can configure 1-rate, 2-color policers for output policy maps with priority. You cannot configure 2-rate,
3-color policers for output policies.
See also the Configuring Output Policy Maps with Class-Based Priority Queuing, page 633 .
Note: You cannot configure a policer committed burst size for an unconditional priority policer. Any configured burst size
is ignored.
This example shows how to use the priority with police commands to configure out-class1 as the priority queue, with
traffic going to the queue limited to 20,000,000 bps so that the priority queue never uses more than that. Traffic above
that rate is dropped. This allows other traffic queues to receive some port bandwidth, in this case a minimum bandwidth
guarantee of 500,000 and 200,000 kbps. The class
class-default queue gets the remaining port bandwidth.