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798 | Power over Ethernet
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Classifying VOIP traffic and applying QoS policies
Avoid congestion and give precedence to voice and signaling traffic by classifying traffic based on subnet
and using strict priority and bandwidth weights on egress, as outlined in the steps below.
Figure 36-12 depicts the topology and shows the configuration for a C-Series. The steps are the same on an
S-Series. Figure 36-13 on page 799 is a screenshot showing some of the steps and the resulting
running-config.
Figure 36-12. Classifying VOIP Traffic and Applying QoS Policies for an Office VOIP Deployment
Figure 36-13 on page 799 is a screenshot showing some of the steps, above, and the resulting
running-config.
Step Task Command Command Mode
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.
ip access-list
class-map match-any
CONFIGURATION
CLASS-MAP
2 Create an input policy-map containing all three class-maps,
and assign each class-map a different service queue.
policy-map-input
service-queue
CONFIGURATION
POLICY-MAP-IN
3 Create two input QoS policies, one each for PC data and
voice signaling. Assign a different bandwidth weight to each
policy.
qos-policy-out
bandwidth-weight
CONFIGURATION
QOS-POLICY-IN
4 Create an output policy map containing both QoS policies,
and assign them to different service queues.
policy-map-out
service-queue
CONFIGURATION
POLICY-MAP-OUT
5 Assign a strict priority to unicast traffic in queue 3.
strict-priority
CONFIGURATION
6 Apply the input policy map you created in Step 2 to the
interface connected to the phone, and apply the output
policy map you created in Step 4 to the interface connected
your desired next-hop router.
service-policy
INTERFACE
6/10
6/2
Force10#sh run int gi 6/2
!
interface GigabitEthernet 6/2
description "Uplink to E1200"
no ip address
switchport
service-policy output BW
no shutdown
E-SeriesC-SeriesIP Phone XPC
PC data
VLAN 300: Voice Signaling
VLAN 200: Voice
LLDP-MED advertisements
Force10#sh run int gi 6/10
!
interface GigabitEthernet 6/10
description "IP Phone X”
no ip address
portmode hybrid
switchport
service-policy input phone-pc
power inline auto
no shutdown
Force10#sh run lldp
protocol lldp
advertise med
advertise med voice 200 6 46
advertise med voice-signaling 300 5 28
no disable
VLAN 100: Data
queue 2, bandwidth weight 64
queue 3, strict priority
queue 1, bandwidth weight 8