Specifications

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Feature Default Value
CoS None
Tail Drop Disabled
Queue 2-7 Threshold 1-8
WRED Disabled
CoS 5
Tail Drop Disabled
Queue 8 Threshold 1
WRED 100% Low; 100% High
CoS None
Tail Drop Disabled
Queue 8 Threshold 2-8
WRED 100% Low; 100% High
These drop thresholds can be changed by the administrator. Also, the default CoS values that are mapped each
threshold can also be changed. Different line cards implement different receive queue implementations. A summary
of the queue types is shown below:
An example of this configuration capability is shown below:
Cat6500(config-if)# rcv-queue threshold 1 60 75 85 100
This command configures the 4 thresholds for a port with a queue structure of 1Q4T RX queue.
Receive drop thresholds must be enabled by the administrator. Currently the “mls qos trust trust-cos” command
should be used at the interface level to activate the receive drop thresholds .
7.9 Configuring Transmit Drop Thresholds
On an egress port, the port will have one of a number of transmit thresholds that are used as part of the congestion
avoidance mechanism. Queue 1 is always denoted as the standard low priority queue and the higher numbered
queues are denoted as the standard higher priority queue. Depending on the line cards used, they will employ either
a tail drop or a WRED threshold management algorithm. Both algorithms employ two thresholds for each transmit
queue.
Figure 27. Output Thresholds
The administrator can manually set these thresholds as follows: