Voip Device Specifics - Cisco Catalyst 2975 Software Configuration Manual

Chapter 33 Configuring QoS

VOIP Device Specifics

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The switch configures ingress and egress queues on the port according to the settings in
Table
Table 33-2 Traffic Types, Packet Labels, and Queues
1
VoIP
Traffic
DSCP 46
CoS 5
CoS-to-Ingress 4, 5 (queue 2)
Queue Map
CoS-to-Egress 4, 5
Queue Map (queue 1)
1. VoIP = voice over IP
Table 33-3
Ingress Queue
SRR shared
Priority
OL-19720-02
When you enter the auto qos voip cisco-phone command on a port at the network edge connected
to a Cisco IP Phone, the switch enables the trusted boundary feature. If the packet does not have a
DSCP value of 24, 26, or 46 or is out of profile, the switch changes the DSCP value to 0. When there
is no Cisco IP Phone, the ingress classification is set to not trust the QoS label in the packet. The
policing is applied to the traffic matching the policy-map classification before the switch enables the
trust boundary feature.
When you enter the auto qos voip cisco-softphone interface configuration command on a port at
the network edge that is connected to a device running the Cisco SoftPhone, the switch uses policing
to determine whether a packet is in or out of profile and to specify the action on the packet. If the
packet does not have a DSCP value of 24, 26, or 46 or is out of profile, the switch changes the DSCP
value to 0.
When you enter the auto qos voip trust interface configuration command on a port connected to the
network interior, the switch trusts the CoS value for nonrouted ports or the DSCP value for routed
ports in ingress packets (the assumption is that traffic has already been classified by other edge
devices).
33-3.
Data VoIP Control Routing Protocol
Traffic Traffic
24, 26 48
3 6
2, 3, 6, 7 (queue 2)
Auto-QoS Configuration for the Ingress Queues
Queue Number
1
2
STP BPDU Real-Time
Traffic Video Traffic
56 34
7 3
0 (queue 3)
Queue Weight
CoS-to-Queue Map (Bandwidth)
0, 1, 2, 3, 6, 7 70 percent
4, 5 30 percent
Catalyst 2975 Switch Software Configuration Guide
Configuring Auto-QoS
Table 33-2 and
All Other Traffic
–
–
0, 1, 2, 3, 6, 7(queue 1)
2 (queue 3) 0, 1
(queue 4)
Queue (Buffer)
Size
90 percent
10 percent
33-21