Cisco 2975 - Catalyst LAN Base Switch, Руководство по настройке программного обеспечения

Страница: 745 / 982

33-21
Catalyst 2975 Switch Software Configuration Guide
OL-19720-02
Chapter 33 Configuring QoS
Configuring Auto-QoS
VOIP Device Specifics
• 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).
The switch configures ingress and egress queues on the port according to the settings in Table 33-2 and
Table 33-3 .
Table 33-2 Traffic Types, Packet Labels, and Queues
VoIP
1
Data
Traffic
1. VoIP = voice over IP
VoIP Control
Traffic
Routing Protocol
Traffic STP BPDU
Traffic Real-Time
Video Traffic
All Other Traffic
DSCP 46 24, 26 48 56 34 –
CoS 5 3 6 7 3 –
CoS-to-Ingress
Queue Map 4, 5 (queue 2) 0, 1, 2, 3, 6, 7(queue 1)
CoS-to-Egress
Queue Map 4, 5
(queue 1)
2, 3, 6, 7 (queue 2) 0 (queue 3) 2 (queue 3) 0, 1
(queue 4)
Table 33-3 Auto-QoS Configuration for the Ingress Queues
Ingress Queue Queue Number CoS-to-Queue Map
Queue Weight
(Bandwidth) Queue (Buffer)
Size
SRR shared 1 0, 1, 2, 3, 6, 7 70 percent 90 percent
Priority 2 4, 5 30 percent 10 percent