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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
Selecting a Distribution-Layer Switch
Step 1
The default CoS-to-DSCP mapping is as follows:
4006-SUPIII-Dist#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 = EF and CoS 3 = AF31 and CoS 4 = AF41.
4006-SUPIII-Dist(config)#qos map cos 3 to dscp 26
4006-SUPIII-Dist(config)#qos map cos 4 to dscp 34
4006-SUPIII-Dist(config)#qos map cos 5 to dscp 46
Configuring Priority Queuing
Turn on priority queuing on a per port basis. Default admission to the priority queue matches our
requirements.
Step 1
Specify the transmit queue.
4006-SUPIII(config-if-tx-queue)#tx-queue 3
Step 2
Set the priority for the queue to high.
4006-SUPIII(config-if-tx-queue)#priority high
Configuring ACLs
Create an ACL to identify the traffic to be marked and create classes that use the ACLs as admission
criteria.
Step 1
Create an ACL to match the traffic you want to prioritize.
4006-SUPIII-Dist(config)#ip access-list extended GOLD-DATA
4006-SUPIII-Dist(config-ext-nacl)#remark Match IP Address of the application server
4006-SUPIII-Dist(config-ext-nacl)#permit ip any host 192.168.100.1
4006-SUPIII-Dist(config-ext-nacl)#permit ip host 192.168.100.1 any
4006-SUPIII-Dist(config)#ip access-list extended VOICE
4006-SUPIII-Dist(config-ext-nacl)#remark Match the UDP ports that VoIP Uses for Bearer
Traffic
4006-SUPIII-Dist(config-ext-nacl)#permit udp any any range 16384 32767
4006-SUPIII-Dist(config)#ip access-list extended VOICE-CONTROL
4006-SUPIII-Dist(config-ext-nacl)#remark Match VoIP Control Traffic
4006-SUPIII-Dist(config-ext-nacl)#remark SCCP
4006-SUPIII-Dist(config-ext-nacl)#permit tcp any any range 2000 2002
4006-SUPIII-Dist(config-ext-nacl)#remark H323 Fast Start
4006-SUPIII-Dist(config-ext-nacl)#permit tcp any any eq 1720
4006-SUPIII-Dist(config-ext-nacl)#remark H323 Slow Start
4006-SUPIII-Dist(config-ext-nacl)#permit tcp any any range 11000 11999
4006-SUPIII-Dist(config-ext-nacl)#remark H323 MGCP
4006-SUPIII-Dist(config-ext-nacl)#permit udp any any eq 2427