Brocade Communications Systems 53-1001761-01 manual Multicast queue scheduling

Scheduling 9

Multicast queue scheduling

The multicast traffic classes are numbered from 0 to 3; higher numbered traffic classes are considered higher priority. A fixed mapping from multicast traffic class to equivalent unicast traffic class is applied to select the queue scheduling behavior. Table 20 presents the multicast traffic class equivalence mapping applied.

TABLE 20	Multicast traffic class equivalence mapping
Multicast traffic class		Equivalent unicast traffic class
3		6
2		4
1		2
0		0

Once the multicast traffic class equivalence mapping has been applied, then scheduling and any scheduler configuration are inherited from the equivalent unicast traffic class. See Table 19 on page 104 for details on exact mapping equivalencies.

Unicast ingress and egress queueing utilizes a hybrid scheduler that simultaneously supports SP+WRR service and multiple physical queues with the same service level. Multicast adds additional multicast expansion queues. Since multicast traffic classes are equivalent to unicast service levels, they're treated exactly as their equivalent unicast service policies.

Scheduling the QoS multicast queue

Perform the following steps from Privileged EXEC mode to schedule the QoS multicast queue. 1. Enter global configuration mode.

switch#configure terminal

2. Specify the schedule to use and the traffic class to bandwidth mapping.

switch(config)#qos queue multicast scheduler dwrr 10 20 30 40

Example of setting the multicast Traffic Class frame expansion scheduler for Traffic Class 0 getting 10 percent bandwidth, Traffic Class 1 getting 20 percent bandwidth, Traffic Class 2 getting 30 percent bandwidth, and Traffic Class 3 getting 40 percent bandwidth.

switch:admin>cmsh switch>enable

switch#configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

switch(config)#qos queue multicast scheduler dwrr 10 20 30 40 switch(config)#end

3. Enter the copy command to save the running-config file to the startup-config file.

switch#copy running-config startup-config

Converged Enhanced Ethernet Administrator’s Guide	105
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