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Chapter 3 QoS in an AVVID-Enabled Campus Network
Selecting a Distribution-Layer Switch
Figure 3-13 General Model for Catalyst 6500 (with Catalyst OS) as a Distribution Switch in QoS
Configurations
For the Catalyst 6500 running Catalyst OS, QoS requires the following changes to the configuration of
the distribution switch:
1.
Configure VoIP control traffic transmit queuing.
2.
Configure the distribution layer with a Layer 3 access switch.
3.
Configure the distribution layer with a Layer 2 access switch.
Configuring the Distribution Layer VoIP Control Traffic Transmit Queue
When QoS is enabled, all VoIP (CoS of 5) traffic is placed into the egress interface priority queue on
1p2q2t interfaces and into queue 2 on 2q2t interfaces (for all versions "1" of the 10/100 line cards). To
configure the Catalyst 6500 CoS queue admission rules to ensure that VoIP control traffic (CoS of 3) is
placed into the second queue, do the following:
Step 1
Change the mapping for the 1p2q2t interfaces.
cat6k-distrib> (enable) set qos map 1p2q2t tx 2 1 cos 3
Step 2
Change the mapping for the 2q2t interfaces.
cat6k-distrib> (enable) set qos map 2q2t tx 2 1 cos 3
Configuring the Distribution Layer with a Layer 3 Switch
Once you have enabled QoS on the distribution layer switch and have modified the default queue
admission, do the following to complete the integration with a Layer 3 access switch:
Si
Si
IP
VVID=112
6500 w/ PFC
4000
3500
VLAN=12
IP
VVID=111
VLAN=11
IP
VVID=110
VLAN=10
Distribution
Access
Hybrid
6500
Native IOS
6500
7200 WAN
router
74704
2/1
2/2
1/2
3/2
9/1
3/1
1/1