Configuring Transmit Queues - Cisco 4500M Software Manual

Chapter 29 Configuring QoS

Configuring Transmit Queues

The following sections describes how to configure the transmit queues:
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Depending on the complexity of your network and your QoS solution, you might need to perform all of
the procedures in the next sections, but first you will need to make decisions about these characteristics:
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Mapping DSCP Values to Specific Transmit Queues
To map the DSCP values to a transmit queue, perform this task:
Command
Step 1
Switch(config)# [no] qos map dscp dscp-values to
tx-queue queue-id
Step 2
Switch(config)# end
Step 3
Switch# show qos maps dscp tx-queues
This example shows how to map DSCP values to transit queue 2.
Switch# configure terminal
Enter configuration commands, one per line.
Switch(config)# qos map dscp 50 to tx-queue 2
Switch(config)# end
Switch#
This example shows how to verify the configuration.
Switch# show qos maps dscp tx-queue
DSCP-TxQueue Mapping Table (dscp = d1d2)
d1 :d2
-------------------------------------
0 :
1 :
2 :
3 :
4 :
5 :
6 :
Switch#
OL-6696-01
Mapping DSCP Values to Specific Transmit Queues, page 29-43
Allocating Bandwidth Among Transmit Queues, page 29-44
Configuring Traffic Shaping of Transmit Queues, page 29-44
Configuring a High Priority Transmit Queue, page 29-45
Which packets are assigned (by DSCP value) to each queue?
What is the size of a transmit queue relative to other queues for a given port?
How much of the available bandwidth is allotted to each queue?
What is the maximum rate and burst of traffic that can be transmitted out of each transmit queue?
0 1 2 3 4 5 6
02 02 02 01 01 01 01 01 01 01
01 01 01 01 01 01 02 02 02 02
02 02 02 02 02 02 02 02 02 02
02 02 03 03 03 03 03 03 03 03
03 03 03 03 03 03 03 03 04 04
04 04 04 04 04 04 04 04 04 04
04 04 04 04
Purpose
Maps the DSCP values to the transit queue. dscp-list can
contain up 8 DSCP values. The queue-id can range from
1 to 4.
Use the no qos map dscp to tx-queue command to clear
the DSCP values from the transit queue.
Exits configuration mode.
Verifies the configuration.
End with CNTL/Z.
7 8 9
Software Configuration Guide—Release 12.2(25)EW
Configuring QoS
29-43