DELL S50V User Manual

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Multicast Features

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Allocate more buffer memory to multicast WRED (Weighted Random Early Detection) for bursty 
multicast traffic that might temporarily become oversubscribed. For example, the example WRED profile 
in 

of buffer memory and up to 60 megabytes.

Egress Weighted Fair Queuing (WFQ) determines per port the ratio of egress bandwidth allocated to 
multicast, replication, and unicast traffic. By default, FTOS provides 1/64 to multicast, 1/64 to replication, 
and 62/64 for unicast, which is shared between 8 unicast queues. Allocate more bandwidth for multicast 
using the command 

 (from CONFIGURATION mode) with the keyword 

. For example, allocate 80% of egress bandwidth to multicast on all line cards using the 

command 

.

The Central Scheduler is responsible for scheduling unicast and multicast packets via the Terabit 
backplane. The default configuration of the Central Scheduler is optimized for network environments that 
forward primarily unicast traffic—80% of the scheduler weight is for unicast traffic and 20% is for 
multicast traffic. 

FTOS provides the ability to adjust the scheduling weight for multicast traffic. For example, if the majority 
of your traffic is multicast, the default configuration might yield greater latency. In this case, allocate more 
backplane bandwidth for multicast using the command 

 from 

CONFIGURATION mode. View your configuration using the command 

. 

FTOS(Conf)#queue egress multicast linecard all wred-profile Egress

FTOS(conf)#wred-profile Egress

FTOS(conf-wred)# threshold min 40960 max 61440

FTOS#show queue backplane multicast bandwidth-percent

Configured multicast bandwidth percentage is 80