Configuring AutoQoS Cisco Catalyst 6500 Switch
Console> (enable)
set qos autoqos
• Global configuration command
• All the global QoS settings are applied to all ports in the switch
• Prompt displays showing 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 <mod/port> autoqos voip <ciscoipphone|ciscosoftphone>
Cisco Public
When you execute the global automatic QoS macro, all the global QoS settings are applied to all ports in the switch. After completion, a prompt displays showing the CLI for the port-based automatic QoS commands currently supported.
The port-specific automatic QoS macro handles all inbound QoS configuration that is specific to a particular port.
The QoS ingress port specific settings include port trust, default 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 if AutoQoS modifies ACL mappings on that port. The ACL names and instances are not changed.
If the trust dscp or trust cos keywords are used, the trusted boundary feature is disabled. This means an IP Phone will not rewrite the dscp or cos values from an attached PC.
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Configuring AutoQoS: Cisco Catalyst 6500 Switch (Cont.) |
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Console> (enable) |
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set port qos autoqos <mod/port> voip [ciscosoftphone | ciscoipphone] |
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• 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 • Only available on Catalyst 6500 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 |
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The port-specific automatic QoS macro accepts a mod/port combination and must include an AVVID-type 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 and voice bearer and PC data entering and leaving the port.
In addition to the switch-side QoS settings covered by the global automatic QoS command, the phone has a few QoS features that need to be configured for proper labeling to occur. QoS configuration information is sent to the phone through CDP from the switch. The QoS values that need to be configured are the trust settings of the "PC port" on the phone (trust or untrusted) and the CoS value that is used by the phone to remark packets in case the port is untrusted (ext-cos).
Only the Catalyst 6500 supports AutoQoS for Cisco SoftPhone. 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 non-priority 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 (EF) inbound traffic to the codec rate used by the Cisco SoftPhone application (worst case G.723). Any traffic that exceeds this rate is marked down to the default traffic rate (DSCP 0 - BE). 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 - BE).
Note You must disable the trusted boundary feature for Cisco SoftPhone ports.
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