Users Guide

Data Center Bridging Features 1145
The minimum bandwidth setting on the CoS queues comes into effect only
when there is congestion among the CoS queues belonging to a single TCG.
This is an optional setting and is not generally required, as the secondary
scheduler has the capability of guaranteeing minimum bandwidth for a TCG.
If this value is set, the sum of the individual minimum bandwidths of the
CoS queues belonging to any TCG should be set to the same value as the
minimum bandwidth value of the TCG in the secondary scheduler, or no
minimum bandwidth value should be configured for the TCG.
CAUTION: Sharing of bandwidth among CoS Queues is disabled if the sum of the
minimum bandwidth settings equals 100%.
console(config-if-Te1/0/1)# cos-queue min-bandwidth 20 35 35 10 0 0 0
4. Configure the Scheduler Mode for the CoS Queues
This step enables strict priority scheduling on one or more CoS queues
(traffic classes). Strict priority scheduling ensures that packets assigned to a
higher CoS queue number are serviced before packets assigned to lower CoS
queue numbers. The strict priority setting does not restrict frame ingress. Use
the 'no' command to disable strict priority mode scheduling.
It is recommended that all queues enabled for strict priority scheduling be
assigned to a single strict-priority-enabled TCG other than TCG0.
The following example sets CoS queue (traffic class) number 3 to be serviced
with strict priority:
console(config-if-Te1/0/1)#cos-queue strict 3
By default, these are packets tagged with IEEE 802.1p user priority 6 and 7.
To show the minimum bandwidth and scheduler modes for CoS queues, use
the following command:
console#show interfaces cos-queue tengigabitethernet 1/0/1
Interface...................................... Te1/0/1
Interface Shaping Rate......................... 0 kbps
WRED Decay Exponent............................ 9
Queue Id Min. Bandwidth Scheduler Type Queue Management Type
-------- -------------- -------------- ---------------------
0 20 Weighted Tail Drop
1 35 Weighted Tail Drop
2 35 Weighted Tail Drop
3 10 Strict Tail Drop