Users Guide

Classifying VoIP Traffic and Applying QoS Policies
You can avoid congestion and give precedence to voice and signaling traffic by classifying traffic based
on the subnet and using strict priority and bandwidth weights on egress, as outlined in the following
steps. The following figure depicts the topology and configuration for a C9000 system.
Figure 109. PoE VoIP Traffic
To classify VoIP traffic and apply QoS policies for an office VoIP deployment, use the following
commands:
1. Create three standard or extended access-lists, one each for voice, voice signaling, and PC data, and
place each in its own match-any class-map.
CONFIGURATION mode or CLASS-MAP mode
ip access-list or class-map match-any
2. Create an input policy-map containing all three class-maps and assign each class-map a different
service queue.
CONFIGURATION mode or POLICY-MAP-IN mode
policy-map-input or service-queue
3. Create two input QoS policies, one each for PC data and voice signaling. Assign a different
bandwidth weight to each policy.
CONFIGURATION mode or QOS-POLICY-IN mode
qos-policy-out or bandwidth-weight
4. Create an output policy map containing both QoS policies and assign them to different service
queues.
822
Power over Ethernet (PoE)