Cisco WS-X6416-GE-MT - Interface Module - Expansion Bedienungsanleitung PDF herunterladen (Seite 36)

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Configuring Interface QoS

Trust State

Ports can be set to trust certain fields such as CoS, IP-precedence, or DSCP in the incoming

frames. The following is a sample configuration:

Cisco Catalyst OS Cisco IOS Software

set port qos 3/1 trust trust-cos Router(config)# interface gigabitethernet 3/1

Router(config-if)# mls qos trust cos

Both the Cisco Catalyst OS and Cisco IOS Software support the Extended Trust feature for

differentiating IP phone voice traffic and workstation data traffic.

Default Port CoS

The switch offers the capability to set a CoS value for all traffic entering a particular port. This is

supported in both operating systems:

Cisco Catalyst OS Cisco IOS Software

set port qos 3/1 cos 3 Router(config)# interface gigabitethernet 3/1

Router(config-if)# mls qos cos 3

Port- and VLAN-Based QoS Mode

QoS policies can be applied either per-port or per-VLAN. By default, QoS functionality is port-

based. In this case, all QoS policies are applied to a particular port. Policies that are applied to a

VLAN will not affect traffic that is ingress on a port which is configured as port-based. If a policy is

mapped to a VLAN, you must inform the interface that QoS is VLAN based for each port in the

VLAN to which the VLAN policy is applicable. The following command when executed on the

intended interfaces alters the default QoS from port-based to VLAN-based:

Cisco Catalyst OS Cisco IOS Software

set port qos 3/1 vlan-based Router(config)#interface gigabitethernet 3/1

Router(config-if)# mls qos vlan-based

CoS-to-Queue Mapping

This section describes the mapping of CoS values to queues/thresholds in the standard receive

and transmit queues. In Cisco IOS Software, the rcv-queue keyword is used for standard receive

queue configuration, the wrr-queue keyword is used for round-robin transmit queues, and the

priority-queue keyword is used for priority queues.

In the Cisco Catalyst OS implementation, the CoS-to-queue mapping is configured per queue type

(that is, all 1p2q2t ports will have the same configuration). In Cisco IOS Software implementation,

the CoS-to-queue mapping is configured per interface and the configuration changes are

implemented on all ports that are managed by the same port ASIC. (ASIC to port layout varies by

line card, but the CLI will issue a warning of the changes made.) The following example maps

802.1p value of 5 to the strict priority queue (rx and tx) and 802.1p values of 0 and 1 to the first

threshold of the low priority queue.

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Cisco WS-X6416-GE-MT - Interface Module - Expansion Bedienungsanleitung Seite 36