Example Configuring the AutoQoS VoIP Feature on a High Speed Serial Interface

In the example, the AutoQoS VoIP feature is configured on the high-speed serial interface s1/2:

Router> enable Router# configure terminal Router(config)# interface s1/2 Router(config-if)# bandwidth 1540 Router(config-if)# auto qos voip Router(config-if)# exit

Console> (enable)

set qos autoqos

• Global configuration command.

• All the global QoS settings are applied to all ports in the switch.

• Prompt displays the CLI for the port-based automatic QoS commands currently supported.

Console>(enable)set qos autoqos QoS is enabled

All ingress and egress QoS scheduling parameters configured on all ports.CoS to DSCP, DSCP to COS, IP Precedence to DSCP and policed dscp maps configured.

Global QoS configured, port specific autoqos recommended: set port qos <mod/port> autoqos trust <cos|dscp>

set port qos ^od/port> autoqos voip <ciscoipphone|ciscosoftphone>

When the global automatic QoS macro is executed, all the global QoS settings are applied to all ports in the switch. After completion, a prompt will display showing the CLI for the port-based automatic QoS commands that are currently supported.

The port-specific automatic QoS macro handles all inbound QoS configurations specific to a particular port.

The QoS ingress port-specific settings include port trust, default class of service (CoS), classification, and policing, but does not include scheduling. Input scheduling is programmed through the global automatic QoS macro. Together with the global automatic QoS macro command, all QoS settings are configured properly for a specific QoS traffic type.

Any existing QoS ACLs that are already associated with a port are removed when AutoQoS modifies ACL mappings on that port. The ACL names and instances are not changed.

Configuring AutoQoS VoIP: Cisco Catalyst 6500 Switch (Cont.)

Console> (enable)

set port qos <mod/port> autoqos voip [ciscosoftphone | ciscoipphone]

• The trusted boundary feature must be disabled for Cisco SoftPhone ports.

• QoS settings must be configured to trust the Layer 3 markings of the traffic that enters the port.

• Available on most Catalyst platforms. ciscoipphone

• The port is set up to trust-cos as well as to enable the trusted boundary feature.

• Combined with the global automatic QoS command, all settings are configured on the switch to properly handle the signaling and voice bearer and PC data entering and leaving the port.

• CDP must be enabled for the ciscoipphone QoS configuration.

— — ™_J

The port-specific automatic QoS macro accepts a mod/port combination and must include a Cisco Architecture for Voice, Video and Integrated Data (Cisco AVVID) type of keyword. The ciscoipphone, ciscosoftphone, and trust keywords are supported.

With the ciscoipphone keyword, the port is set up to trust-cos as well as to enable the trusted boundary feature. Combined with the global automatic QoS command, all settings are configured on the switch to properly handle the signaling, voice bearer, and PC data entering and leaving the port.

In addition to the switch-side QoS settings that are covered by the global automatic QoS command, the IP Phone has a few QoS features that need to be configured for proper labeling to occur. QoS configuration information is sent to the IP Phone through CDP from the switch. The QoS values that need to be configured are the trust settings of the "PC port" on the IP Phone (trusted or untrusted) and the CoS value that is used by the IP Phone to re-mark packets in case the port is untrusted (ext-cos).

On the ports that connect to a Cisco SoftPhone, QoS settings must be configured to trust the Layer 3 markings of the traffic that enters the port. Trusting all Layer 3 markings is a security risk, because PC users could send nonpriority traffic with DSCP 46 and gain unauthorized performance benefits. Although not configured by AutoQos, policing on all inbound traffic can be used to prevent malicious users from obtaining unauthorized bandwidth from the network. Policing is accomplished by rate-limiting the DSCP 46 (Expedited Forwarding [EF]) inbound traffic to the codec rate used by the Cisco SoftPhone application (worst case G.722). Any traffic that exceeds this rate is marked down to the default traffic rate (DSCP 0, or Best Effort). Signaling traffic (DSCP 24) is also policed and marked down to zero if excess signaling traffic is detected. All other inbound traffic types are reclassified to default traffic (DSCP 0, or Best Effort).

Note You must disable the trusted boundary feature for Cisco SoftPhone ports.

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