Benefits and Drawbacks of MDRR

Benefits and Drawbacks of MDRR

• Benefits
• Accurate bandwidth allocation (takes into account the deficit from the previous round as opposed to custom queuing)
• Prevents head-of-line blocking in front of the crossbar switching fabric
• Supports low-latency queuing (strict priority and alternate priority)
• High performance
• Drawbacks
• Limited classification tools (only IP Precedence)
• Limited number of classes (only eight)
• Supported only on Cisco 12000 Series GSRs

Configuring Interface MDRR

• cos-queue-group cos-queue-group-name

• Router(config)#

• Create a queue group template and enter CoS queue group configuration mode.

• precedence precedence queue {queue-number|low-latency}

• Router(config-cos-que)#

• Map IP Precedence to a queue.

• queue queue-number weight

• Router(config-cos-que)#

• Set the weight of a queue.

Configuring Interface MDRR (cont.)

• tx-cos cos-queue-group-name

• Router(config-if)#

• Associate a CoS queue group name with the transmit queues on an interface.

• queue low-latency {alternate-priority weight|strict-priority}

• Router(config-cos-que)#

• Specify the type of low-latency queue.

Configuring Receive MDRR

• slot-table-cos slot-table-name

• Router(config)#

• Define a slot table name and enter slot table configuration mode.

• destination slot {slot-number|all} cos-queue-group-name

• Router(config-slot-cos)#

• Define destination slot parameters for this slot table name.

• rx-cos-slot line-card-number cos-queue-group-name

• Router(config)#

• Link a slot-table-cos template to a line card.