Configuring Weighted Fair Queueing

The following example enables DWFQ on the HSSI interface 0/0/0:

Router(config)# interface Hssi0/0/0
Router(config-if)# description 45Mbps to R2
Router(config-if)# ip address 200.200.14.250 255.255.255.252
Router(config-if)# fair-queue

The following is sample output from the show interfaces fair-queue command for this configuration:

Router# show interfaces hssi 0/0/0 fair-queue
Hssi0/0/0 queue size 0
     packets output 35, drops 0
WFQ: global queue limit 401, local queue limit 200

The following example configures QoS-group-based DWFQ. Committed access rate (CAR) policies are used to assign packets with an IP Precedence value of 2 to QoS group 2, and packets with an IP Precedence value of 6 are assigned to QoS group 6.

Router(config)# interface Hssi0/0/0
Router(config-if)# ip address 188.1.3.70 255.255.255.0
Router(config-if)# rate-limit output access-group rate-limit 6 155000000 2000000 8000000 conform-action set-qos-transmit 6 exceed-action drop
Router(config-if)# rate-limit output access-group rate-limit 2 155000000 2000000 8000000 conform-action set-qos-transmit 2 exceed-action drop
Router(config-if)# fair-queue qos-group
Router(config-if)# fair-queue qos-group 2 weight 10
Router(config-if)# fair-queue qos-group 2 limit 27
Router(config-if)# fair-queue qos-group 6 weight 30
Router(config-if)# fair-queue qos-group 6 limit 27
!
Router(config)# access-list rate-limit 2 2
Router(config)# access-list rate-limit 6 6

The following sample output shows how to view WFQ statistics using the show interfaces fair-queue command:

Router# show interfaces fair-queue
 Hssi0/0/0 queue size 0
        packets output 806232, drops 1
 WFQ: aggregate queue limit 54, individual queue limit 27
    max available buffers 54
 
     Class 0: weight 60 limit 27 qsize 0 packets output 654 drops 0
     Class 2: weight 10 limit 27 qsize 0 packets output 402789 drops 0
     Class 6: weight 30 limit 27 qsize 0 packets output 402789 drops 1

The following example configures type of service (ToS)-based DWFQ using the default parameters:

Router# configure terminal
Router(config)# interface Hssi0/0/0
Router(config-if)# fair-queue tos
Router(config-if)# end

The following is output of the show running-config command for the HSSI interface 0/0/0. Notice that the router automatically adds the default weights and limits for the ToS classes to the configuration.

interface Hssi0/0/0
 ip address 188.1.3.70 255.255.255.0
 fair-queue tos
 fair-queue tos 1 weight 20
 fair-queue tos 1 limit 27
 fair-queue tos 2 weight 30
 fair-queue tos 2 limit 27
 fair-queue tos 3 weight 40
 fair-queue tos 3 limit 27

The following sample output shows how to view DWFQ statistics using the show interfaces fair-queue command:

Router# show interfaces fair-queue
 Hssi0/0/0 queue size 0
        packets output 1417079, drops 2
 WFQ: aggregate queue limit 54, individual queue limit 27
    max available buffers 54
 
     Class 0: weight 10 limit 27 qsize 0 packets output 1150 drops 0
     Class 1: weight 20 limit 27 qsize 0 packets output 0 drops 0
     Class 2: weight 30 limit 27 qsize 0 packets output 775482 drops 1
     Class 3: weight 40 limit 27 qsize 0 packets output 0 drops 0

In the following example, ACLs 101 and 102 are created. Next, two class maps are created and their match criteria are defined. For the first map class, called class1, the numbered ACL 101 is used as the match criterion. For the second map class, called class2, the numbered ACL 102 is used as the match criterion. Packets are checked against the contents of these ACLs to determine if they belong to the class.

Router(config)# access-list 101 permit udp host 10.10.10.10 host 10.10.10.20 range 16384 20000
Router(config# access-list 102 permit udp host 10.10.10.10 host 10.10.10.20 range 53000 56000
Router(config)# class-map class1
Router(config-cmap)# match access-group 101
Router(config-cmap)# exit
Router(config-cmap)# class-map class2
Router(config-cmap)# match access-group 102
Router(config-cmap)# exit

In the following example, a policy map called policy1 is defined to contain policy specification for the two classes, class1 and class2. The match criteria for these classes were defined in the previous "Example Class Map Configuration" section.

For class1, the policy specifies the bandwidth allocation request and the maximum number of packets that the queue for this class can accumulate. For class2, the policy specifies only the bandwidth allocation request, so the default queue limit of 64 packets is assumed.

Router(config)# policy-map policy1
Router(config-pmap)# class class1
Router(config-pmap-c)# bandwidth 3000
 
Router(config-pmap-c)# queue-limit 30
Router(config-pmap-c)# exit
Router(config-pmap)# class class2
Router(config-pmap-c)# bandwidth 2000
 
Router(config-pmap-c)# exit

The following example shows how to attach an existing policy map. After you define a policy map, you can attach it to one or more interfaces to specify the service policy for those interfaces. Although you can assign the same policy map to multiple interfaces, each interface can have only one policy map attached at the input and one policy map attached at the output.

The policy map in this example was defined in the previous section, "Example Policy Creation."

Router(config)# interface e1/1
Router(config-if)# service output policy1
 
Router(config-if)# exit
Router(config)# interface fa1/0/0
Router(config-if)# service output policy1
 
Router(config-if)# exit

In the following example, the class map called class1 is created and defined to use the input FastEthernet interface 0/1 as a match criterion to determine if packets belong to the class. Next, the policy map policy1 is defined to contain policy specification for class1, which is configured for WRED packet drop.

Router(config)# class-map class1
Router(config-cmap)# match input-interface FastEthernet0/1
!
Router(config)# policy-map policy1
Router(config-pmap)# class class1
Router(config-pmap-c)# bandwidth 1000
Router(config-pmap-c)# random-detect
!
Router(config)# interface serial0/0
Router(config-if)# service-policy output policy1
!

The following examples show how to display the contents of service policy maps. Four methods can be used to display the contents.

In the following example, two traffic classes are created and their match criteria are defined. For the first traffic class, called class1, the numbered ACL 101 is used as the match criterion. For the second traffic class, called class2, the numbered ACL 102 is used as the match criterion. Packets are checked against the contents of these ACLs to determine if they belong to the traffic class.

Router(config)# class-map class1

Router(config-cmap)# match access-group 101
Router(config-cmap)# exit
Router(config)# class-map class2

Router(config-cmap)# match access-group 102
Router(config-cmap)# exit

In the following example, a traffic policy called policy1 is defined to associate QoS features with the two traffic classes, class1 and class2. The match criteria for these traffic classes were defined in the previous "Example Class Map Configuration" section.

For class1, the QoS policies include bandwidth allocation request and maximum packet count limit for the queue reserved for the traffic class. For class2, the policy specifies only a bandwidth allocation request, so the default queue limit of 64 packets is assumed.

Router(config)# policy-map policy1
Router(config-pmap)# class class1
Router(config-pmap-c)# bandwidth 3000 
Router(config-pmap-c)# queue-limit 30
Router(config-pmap)# exit
Router(config-pmap)# class class2
Router(config-pmap-c)# bandwidth 2000 
Router(config-pmap)# exit

The following example shows how to attach an existing traffic policy to an interface. After you define a traffic policy, you can attach it to one or more interfaces to specify a traffic policy for those interfaces. Although you can assign the same traffic policy to multiple interfaces, each interface can have only one traffic policy attached at the input and one policy map attached at the output at one time.

Router(config)# interface fe1/0/0

Router(config-if)# service output policy1
 
Router(config-if)# exit

The following example first defines a CBWFQ configuration and then reserves a strict priority queue:

! The following commands define a class map:
Router(config)# class-map class1
Router(config-cmap)# match access-group 101
Router(config-cmap)# exit
! The following commands create and attach a policy map:
Router(config)# policy-map policy1
Router(config-pmap)# class class1
Router(config-pmap-c)# bandwidth 3000
Router(config-pmap-c)# queue-limit 30
Router(config-pmap-c)# random-detect
Router(config-pmap-c)# random-detect precedence 0 32 256 100
Router(config-pmap-c)# exit
Router(config)# interface Serial1
Router(config-if)# service-policy output policy1
! The following command reserves a strict priority queue:
Router(config-if)# ip rtp priority 16384 16383 40

The queue-limitand random-detectcommands are optional commands for CBWFQ configurations. The queue-limitcommand is used for configuring tail drop limits for a class queue. The random-detectcommand is used for configuring RED drop limits for a class queue, similar to the random-detect command available on an interface.

The following example configures a strict priority queue in a virtual template configuration with CBWFQ.

Router(config)# multilink virtual-template 1
Router(config)# interface virtual-template 1
Router(config-if)# ip address 172.16.1.1 255.255.255.0
Router(config-if)# no ip directed-broadcast
Router(config-if)# ip rtp priority 16384 16383 25
Router(config-if)# service-policy output policy1
Router(config-if)# ppp multilink
Router(config-if)# ppp multilink fragment-delay 20
Router(config-if)# ppp multilink interleave
Router(config-if)# end
Router(config)# interface Serial0/1
Router(config-if)# bandwidth 64
Router(config-if)# ip address 1.1.1.2 255.255.255.0
Router(config-if)# no ip directed-broadcast
Router(config-if)# encapsulation ppp
Router(config-if)# ppp multilink
Router(config-if)# end

Note	To make the virtual access interface function properly, the bandwidth policy-map class configuration command should not be configured on the virtual template. It needs to be configured on the actual interface, as shown in the example.

The following example configures a strict priority queue in a multilink bundle configuration with WFQ. The advantage to using multilink bundles is that you can specify different ip rtp priority parameters on different interfaces.

The following commands create multilink bundle 1, which is configured for a maximum ip rtp priority bandwidth of 200 kbps.

Router(config)# interface multilink 1
Router(config-if)# ip address 172.17.254.161 255.255.255.248
Router(config-if)# no ip directed-broadcast
Router(config-if)# ip rtp priority 16384 16383 200
Router(config-if)# no ip mroute-cache
Router(config-if)# fair-queue 64 256 0
Router(config-if)# ppp multilink
Router(config-if)# ppp multilink fragment-delay 20
Router(config-if)# ppp multilink interleave

The following commands create multilink bundle 2, which is configured for a maximum ip rtp priority bandwidth of 100 kbps:

Router(config)# interface multilink 2
Router(config-if)# ip address 172.17.254.162 255.255.255.248
Router(config-if)# no ip directed-broadcast
Router(config-if)# ip rtp priority 16384 16383 100
Router(config-if)# no ip mroute-cache
Router(config-if)# fair-queue 64 256 0
Router(config-if)# ppp multilink
Router(config-if)# ppp multilink fragment-delay 20
Router(config-if)# ppp multilink interleave

In the next part of the example, the multilink-group command configures serial interface 2/0 to be part of multilink bundle 1:

Router(config)# interface serial 2/0
Router(config-if)# bandwidth 256
Router(config-if)# no ip address
Router(config-if)# no ip directed-broadcast
Router(config-if)# encapsulation ppp
Router(config-if)# no ip mroute-cache
Router(config-if)# no fair-queue
Router(config-if)# clockrate 256000
Router(config-if)# ppp multilink
Router(config-if)# multilink-group 1

Next, serial interface 2/1 is configured to be part of multilink bundle 2.

Router(config)# interface serial 2/1
Router(config-if)# bandwidth 128
Router(config-if)# no ip address
Router(config-if)# no ip directed-broadcast
Router(config-if)# encapsulation ppp
Router(config-if)# no ip mroute-cache
Router(config-if)# no fair-queue
Router(config-if)# clockrate 128000
Router(config-if)# ppp multilink
Router(config-if)# multilink-group 2

The following example shows sample output from the debug priority command. In this example, 64 indicates the actual priority queue depth at the time the packet was dropped.

Router# debug priority
*Feb 28 16:46:05.659:WFQ:dropping a packet from the priority queue 64
*Feb 28 16:46:05.671:WFQ:dropping a packet from the priority queue 64
*Feb 28 16:46:05.679:WFQ:dropping a packet from the priority queue 64
*Feb 28 16:46:05.691:WFQ:dropping a packet from the priority queue 64
*Feb 28 16:46:05.699:WFQ:dropping a packet from the priority queue 64
*Feb 28 16:46:05.711:WFQ:dropping a packet from the priority queue 64
*Feb 28 16:46:05.719:WFQ:dropping a packet from the priority queue 64

The following example first configures the Frame Relay map class called voip and then applies the map class to PVC 100 to provide strict priority service to matching RTP packets. In this example, RTP packets on PVC 100 with UDP ports in the range 16384 to 32764 will be matched and given strict priority service.

map-class frame-relay voip
 frame-relay cir 256000
 frame-relay bc 2560
 frame-relay be 600
 frame-relay mincir 256000
 no frame-relay adaptive-shaping
 frame-relay fair-queue
 frame-relay fragment 250
 frame-relay ip rtp priority 16384 16380 210
interface Serial5/0
 ip address 10.10.10.10 255.0.0.0
 no ip directed-broadcast
 encapsulation frame-relay
 no ip mroute-cache
 load-interval 30
 clockrate 1007616
 frame-relay traffic-shaping
 frame-relay interface-dlci 100
  class voip
 frame-relay ip rtp header-compression
 frame-relay intf-type dce

In the following example, a strict priority queue with a guaranteed allowed bandwidth of 50 kbps is reserved for traffic that is sent from the source address 10.10.10.10 to the destination address 10.10.10.20, in the range of ports 16384 through 20000 and 53000 through 56000.

First, the following commands configure access list 102 to match the desired voice traffic:

Router(config)# access-list 102 permit udp host 10.10.10.10 host 10.10.10.20 range 16384 20000
Router(config)# access-list 102 permit udp host 10.10.10.10 host 10.10.10.20 range 53000 56000

Next, the class map voice is defined, and the policy map called policy1 is created; a strict priority queue for the class voice is reserved, a bandwidth of 20 kbps is configured for the class bar, and the default class is configured for WFQ. The service-policy command then attaches the policy map to the PVC interface 0/102 on the subinterface atm1/0.2.

Router(config)# class-map voice
Router(config-cmap)# match access-group 102
Router(config)# policy-map policy1
Router(config-pmap)# class voice
Router(config-pmap-c)# priority 50
Router(config-pmap)# class bar
Router(config-pmap-c)# bandwidth 20
Router(config-pmap)# class class-default
Router(config-pmap-c)# fair-queue
Router(config)# interface atm1/0.2
Router(config-subif)# pvc 0/102
Router(config-subif-vc)# service-policy output policy1

The following example configures a strict priority queue in a virtual template configuration with CBWFQ. Traffic on virtual template 1 that is matched by access list 102 will be directed to the strict priority queue.

First, the class map voice is defined, and the policy map called policy1 is created. A strict priority queue (with a guaranteed allowed bandwidth of 50 kbps) is reserved for the class called voice.

Router(config)# class-map voice
Router(config-cmap)# match access-group 102
Router(config)# policy-map policy1
Router(config-pmap)# class voice
Router(config-pmap-c)# priority 50

Next, the service-policy command attaches the policy map called policy1 to virtual template 1.

Router(config)# multilink virtual-template 1
Router(config)# interface virtual-template 1
Router(config-if)# ip address 172.16.1.1 255.255.255.0
Router(config-if)# no ip directed-broadcast
Router(config-if)# service-policy output policy1
Router(config-if)# ppp multilink
Router(config-if)# ppp multilink fragment-delay 20
Router(config-if)# ppp multilink interleave
Router(config-if)# end
Router(config)# interface serial 2/0
Router(config-if)# bandwidth 256
Router(config-if)# no ip address
Router(config-if)# no ip directed-broadcast
Router(config-if)# encapsulation ppp
Router(config-if)# no fair-queue
Router(config-if)# clockrate 256000
Router(config-if)# ppp multilink

The following example configures a strict priority queue in a multilink bundle configuration with CBWFQ. Traffic on serial interface 2/0 that is matched by access list 102 will be directed to the strict priority queue. The advantage to using multilink bundles is that you can specify different priority parameters on different interfaces. To specify different priority parameters, you would configure two multilink bundles with different parameters.

First, the class map voice is defined, and the policy map called policy1 is created. A strict priority queue (with a guaranteed allowed bandwidth of 50 kbps) is reserved for the class called voice.

Router(config)# class-map voice
Router(config-cmap)# match access-group 102
Router(config)# policy-map policy1
Router(config-pmap)# class voice
Router(config-pmap-c)# priority 50

The following commands create multilink bundle 1. The policy map called policy1 is attached to the bundle by the service-policy command.

Router(config)# interface multilink 1
Router(config-if)# ip address 172.17.254.161 255.255.255.248
Router(config-if)# no ip directed-broadcast
Router(config-if)# no ip mroute-cache
Router(config-if)# service-policy output policy1
Router(config-if)# ppp multilink
Router(config-if)# ppp multilink fragment-delay 20
Router(config-if)# ppp multilink interleave

In the next part of the example, the multilink-group command configures serial interface 2/0 to be part of multilink bundle 1, which effectively directs traffic on serial interface 2/0 that is matched by access list 102 to the strict priority queue:

Router(config)# interface serial 2/0
Router(config-if)# bandwidth 256
Router(config-if)# no ip address
Router(config-if)# no ip directed-broadcast
Router(config-if)# encapsulation ppp
Router(config-if)# no fair-queue
Router(config-if)# clockrate 256000
Router(config-if)# ppp multilink
Router(config-if)# multilink-group 1

The priority command can be enabled on an ATM subinterface, and that subinterface must have only one enabled ATM PVC. This configuration provides a sufficient amount of ATM PVC support.

In the following example, a priority queue with a guaranteed allowed bandwidth of 50 kbps is reserved for traffic that is sent from the source address 10.10.10.10 to the destination address 10.10.10.20, in the range of ports 16384 through 20000 and 53000 through 56000.

First, the following commands configure access list 102 to match the desired voice traffic:

Router(config)# access-list 102 permit udp host 10.10.10.10 host 10.10.10.20 range 16384 20000
Router(config)# access-list 102 permit udp host 10.10.10.10 host 10.10.10.20 range 53000 56000

Next, the traffic class called voice is defined, and the policy map called policy1 is created; a priority queue for the class voice is reserved with a guaranteed allowed bandwidth of 50 kpbs and an allowable burst size of 60 bytes, a bandwidth of 20 kbps is configured for the class called bar, and the default class is configured for flow-based fair queuing. The service-policy command then attaches the policy map to the PVC interface 0/102 on the subinterface atm1/0.

Router(config)# class-map voice
Router(config-cmap)# match access-group 102
Router(config)# policy-map policy1
Router(config-pmap)# class voice
Router(config-pmap-c)# priority 50 60
Router(config-pmap)# class bar
Router(config-pmap-c)# bandwidth 20
Router(config-pmap)# class class-default
Router(config-pmap-c)# fair-queue
Router(config)# interface atm1/0
Router(config-subif)# pvc 0/102
Router(config-subif)# service-policy output policy1

The priority percentcommand can be enabled on an ATM subinterface, and that subinterface must have only one enabled ATM PVC. This configuration provides a sufficient amount of ATM PVC support.

In the following example, a priority queue with a guaranteed allowed bandwidth percentage of 15 percent is reserved for traffic that is sent from the source address 10.10.10.10 to the destination address 10.10.10.20, in the range of ports 16384 through 20000 and 53000 through 56000.

First, the following commands configure access list 102 to match the desired voice traffic:

Router(config)# access-list 102 permit udp host 10.10.10.10 host 10.10.10.20 range 16384 20000
Router(config)# access-list 102 permit udp host 10.10.10.10 host 10.10.10.20 range 53000 56000

Next, the traffic class called voice is defined, and the policy map called policy1 is created; a priority queue for the class voice is reserved with a guaranteed allowed bandwidth percentage of 15 percent, a bandwidth percentage of 20 percent is configured for the class called bar, and the default class is configured for flow-based fair queueing. The service-policy command then attaches the policy map to the ATM subinterface 1/0.2.

Router(config)# class-map voice
Router(config-cmap)# match access-group 102
Router(config)# policy-map policy1
Router(config-pmap)# class voice
Router(config-pmap-c)# priority percent 15
Router(config-pmap)# class bar
Router(config-pmap-c)# bandwidth percent 20
Router(config-pmap)# class class-default
Router(config-pmap-c)# fair-queue
Router(config)# interface atm1/0.2
Router(config-subif)# service-policy output policy1

In the following example, the number of particles on the transmission ring of an ATM interface is limited to seven particles:

Router(config)# interface atm 1/0/0
Router(config-if)# atm pvc 32 0 32 tx-ring-limit 7

In the following example, the number of particles on the transmission ring of an ATM PVC subinterface is limited to ten particles:

Router(config)# 
interface ATM1/0/0.1 point-to-point
Router(config-subif)# 
pvc 2/200
Router(config-if-atm-vc)# 
tx-ring-limit 10

The tx-ring-limit command can be applied to several ATM PVC subinterfaces on a single interface. Every individual PVC can configure a transmission ring limit.