QoS Configuration Checklist

Configuring Access Layer QoS for Voice on Cisco Catalyst 6500 with Cisco IOS SW

For the Cisco Catalyst 6500 to act as an access switch for a Cisco 7940/7960/7970 IP phone + PC, using a "full trust" policy, the following is required:

1. Enable switchwide QoS.

2. Configure interfaces used for IP phones:
• Enable trust so the switch accepts the phone class-of-service (CoS) markings.
• Extend the trust boundary to the access port on the IP phone and mark PC traffic as CoS = 0.
• Enable input queue scheduling.
• Configure CoS-to-queue mapping.
• Configure output scheduling.
• Configure CoS-to-differentiated services code point (DSCP) mapping.
• Optionally configure a policy for additional application traffic marking or policing (not covered).

3. Configure the uplink interfaces to the distribution switch:
• Enable trust to accept markings from the distribution switch. This can be either CoS or DSCP trust.
• Enable input queue scheduling.
• Configure CoS-to-queue mapping.
• Configure output scheduling.
• Verify and configure CoS-to-DSCP mapping.
• Optionally configure a policy for additional application traffic marking or policing (not covered).