Users Guide

Layer 2 Switching Commands 725
Command Mode
Global Configuration mode or Interface Configuration (gigabitethernet,
port-channel, tengigabitethernet, fortygigabitethernet) mode
User Guidelines
This command changes the scheduling policy for packet transmission of the
selected CoS queues. It does not change the packet buffering policy nor does
it reserve packet buffers to a CoS queue.
The maximum number of queues supported per interface is seven. It is
recommended that the operator avoid the use of queue 5-7 to avoid conflicts
with inter- and intra-network control traffic.
In order to better accommodate bursty traffic, it is recommended that the
sum of the configured min-bandwidths be much less than 100%. Configuring
the minimum bandwidths such that they sum to 100% effectively locks the
scheduler such that bandwidth sharing by lower priority queues cannot be
accommodated under congestion conditions.
Example
The following example displays how to specify the minimum transmission
bandwidth guarantee for cos-queues 0 through 6 as follows:
Cos Queue 0—5% scheduler capacity
CoS Queue 1—5% scheduler capacity
CoS Queue 2—10% scheduler capacity
CoS Queue 3—10% scheduler capacity
CoS Queue 4-7—Shared scheduler capacity.
console(config)#cos-queue min-bandwidth 5 5 10 10 0 0 0
cos-queue random-detect
Use the cos-queue random-detect command in Global Configuration or
Interface Configuration mode to enable WRED queue management policy
on an interface CoS queue. Use the no form of the command to disable
WRED policy for a CoS queue on an interface.
NOTE: On the N1500 Series switches, this command enables Simple
RED since the hardware is not capable of Weighted RED.