Example: Compound Shared Shaping for ATM VCs

Figure 28 illustrates a typical DSL triple-play configuration, involving voice, video, and data traffic. In this example, a total of 1 Mbps of bandwidth is allocated to voice, video, and best-effort data traffic associated with the VC 1 logical interface.

The voice queue in the EF traffic-class group for VC 1 is a strict constituent that has first claim on up to 200 Kbps of the shared bandwidth. The video queue in the AF traffic-class group is a strict constituent that can claim up to 300 Kbps of the remaining 800–1000 Kbps of shared bandwidth. The best-effort queue for logical interface VC 1 is a strict constituent that has the last claim to the remaining 500–1000 Kbps of shared bandwidth.

Figure 28: VC Compound Shared Shaping Example

VC Compound Shared Shaping Example

To configure VC compound shared shaping:

  1. Configure the traffic classes, traffic-class groups, and additional scheduler profiles.
  2. Configure the scheduler profile that defines the shared shaper and the profiles that apply the legacy shaper.
    host1(config)#scheduler-profile shared-1Mbps host1(config-scheduler-profile)#shared-shaping-rate 1000000 burst 32768 auto host1(config)#scheduler-profile 300Kbps host1(config-scheduler-profile)#shaping-rate 300000 host1(config)#scheduler-profile 200Kbps host1(config-scheduler-profile)#shaping-rate 200000
  3. Configure the QoS profile.
    host1(config)#qos-profile vcSharedShaping
  4. Create group nodes.
    host1(config-qos-profile)#atm group AF scheduler-profile default host1(config-qos-profile)#atm group EF scheduler-profile default
  5. Create VC nodes for each group and for traffic in the default group.
    host1(config-qos-profile)#atm-vc node host1(config-qos-profile)#atm-vc node group AF host1(config-qos-profile)#atm-vc node group EF
  6. Create queues for the best-effort, video, and voice traffic. Apply the scheduler profile that defines the shared-shaping rate to the best-effort queue. Apply the legacy shaper profiles to the voice and video traffic queues.
    host1(config-qos-profile)#atm-vc queue traffic-class best-effort scheduler-profile shared-1mbps host1(config-qos-profile)#atm-vc queue traffic-class video scheduler-profile 300Kbps host1(config-qos-profile)#atm-vc queue traffic-class voice scheduler-profile 200Kbps host1(config-qos-profile)#exit
  7. Attach the QoS profile to an ATM subinterface.
    host1(config)#interface atm 11/0.1 host1(config-interface)#qos-profile vcSharedShaping host1(config-interface)#exit

In this example, the constituents of the VC shared shaper are the VC 1 best effort node, the VC 1 Group EF node, and the VC 1 Group AF node. The available bandwidth is strictly allocated in the following order:

  1. VC 1 EF group node
  2. VC 1 AF group node
  3. VC 1 best effort node

To display the sample shared shaper configuration:

host1# show shared-shaper atm 11/0.1
                 shared  current
                 shaping shaping                           shaping
   interface      rate    rate           resource           rate
---------------- ------- ------- ------------------------- -------
atm-vc ATM11/0.1 1000000 compound best-effort atm-vc queue       
                                  atm-vc best-effort node        
                                  EF voice atm-vc queue     200000
                                  AF video atm-vc queue     300000
atm-vc ATM11/0.2 1000000 compound best-effort atm-vc queue       
                                  atm-vc best-effort node        
                                  EF voice atm-vc queue     200000
                                  AF video atm-vc queue     300000
 Total shared shapers: 2
 Total constituents:   8
 Total failovers:      0

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