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Cisco AVVID Network Infrastructure Enterprise Quality of Service Design
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Chapter 3 QoS in an AVVID-Enabled Campus Network
Server Farm Switch Selection
To verify, issue the following command (shown with its associated output):
4006-SUPIII-Access#show qos
QoS is enabled globally
Step 2
The default CoS-to-DSCP maps must be modified to allow us to trust CoS and maintain DSCP EF and
AF31 for VoIP bearer and control traffic respectively.
4006-SUPIII-Access#show qos map cos
CoS-DSCP Mapping Table
CoS: 0 1 2 3 4 5 6 7
--------------------------------
DSCP: 0 8 16
24 32 40 48 56
Change the default CoS-to-DSCP mapping so that CoS 5 equates to EF, CoS 3 equates to AF31, and
CoS 4 equates to AF41.
4006-SUPIII-Access(config)#qos map cos 3 to dscp 26
4006-SUPIII-Access(config)#qos map cos 4 to dscp 34
4006-SUPIII-Access(config)#qos map cos 5 to dscp 46
To verify, issue the following command (shown with its associated output):
4006-SUPIII-Access#show qos map cos
CoS-DSCP Mapping Table
CoS: 0 1 2 3 4 5 6 7
--------------------------------
DSCP: 0 8 16
26 34 46 48 56
4006-SUPIII-Access#show qos map dscp tx-queue
DSCP-TxQueue Mapping Table (dscp = d1d2)
d1 : d2 0 1 2 3 4 5 6 7 8 9
-------------------------------------
0 : 01 01 01 01 01 01 01 01 01 01
1 : 01 01 01 01 01 01 02 02 02 02
2 : 02 02 02 02 02 02 02 02 02 02
3 : 02 02 03 03 03 03 03 03 03 03
4 : 03 03 03 03 03 03 03 03 04 04
5 : 04 04 04 04 04 04 04 04 04 04
6 : 04 04 04 04
Step 3
Turn on priority queuing. The default admission to the priority queue is sufficient for our requirements.
4006-SUPIII-Access(config-if-tx-queue)#tx-queue 3
4006-SUPIII-Access(config-if-tx-queue)#priority high
To verify, issue the following command (shown with its associated output):
4006-SUPIII-Access#show qos inter fa 3/4
QoS is enabled globally
Port QoS is enabled
Port Trust State: 'untrusted'
Default DSCP: 0 Default CoS: 0
Tx-Queue Bandwidth ShapeRate Priority QueueSize
(bps) (bps) (packets)
1 N/A disabled N/A 240
2 N/A disabled N/A 240
3 N/A disabled high 240
4 N/A disabled N/A 240