Brocade Multi-Service IronWare QoS and Traffic Management Configuration Guide (Supporting R05.6.00) - Manual (Page 84)

70 Multi-Service IronWare QoS and Traffic Management Configuration Guide
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Egress port and priority based rate shaping
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Multicast descriptor limit
Brocade NetIron CES and Brocade NetIron CER require a descriptor to place the packet in queue. If
due to traffic conditions the descriptor limit is reached, the subsequent packets are dropped until
the descriptors are available again. This parameter specifies the maximum number of descriptors
that can be allocated for multicast packets. In a multicast intensive environment you may want to
assign a higher value for the multicast descriptor limit. The default value of this is 2048.
Brocade(config)# qos-multicast mcast-desc-limit 8000
Syntax: [no] qos-multicast mcast-desc-limit limit-value [ppcr <ppcr_id>]
The limit_value parameter has a default value of 2048. Valid values include 0 - 8192.
The ppcr_id parameter is an optional keyword. Valid values: 0 - for ports e1/1 - e1/24; 1 - for ports
e1/25 - e1/28; 2 - for ports e2/1 - e2/2.
Without the ppcr id the command will set the limit value on all packet processors. If the ppcr id is
specified then the command will set the limit value on only that packet processor.
Multicast Traffic class mapping to Fabric Traffic class
The multicast traffic class is mapped to Fabric traffic class. Multicast TC 0, 1 is mapped to Fabric
TC 0, Multicast TC 2,3 is mapped to Fabric TC 1, Multicast TC 4, 5 is mapped to Fabric TC 2,
Multicast TC 6,7 is mapped to fabric TC 3. In the Egress Pipeline if Fabric TC is 2 and it is a
multicast packet, the buffering of the descriptors occurs in a deep queue. This is a queue generally
used in IPTV applications. You may want to change this mapping to assign all the multicast Traffic
class to Fabric Traffic class 2 to utilize the deep buffer queue. This will improve the performance of
IPTV applications.
Brocade(config)# qos-multicast mcast-tc-to-iptv all
Syntax: [no] qos-multicast mcast-tc-to-iptv tc-value | all
The tc_value parameter is the Multicast traffic class that needs to mapped to Fabric traffic class 2.
Valid values include 0 - 7. All will map all multicast traffic classes to Fabric class 2.