Can be applied to either a router or switch


  • router(config-if)# auto qos voip   # enable and configure  it on the interface

  • router(config-if) or (config-fr-dlci)# auto qos voip [trust] [fr-atm] # configures the AutoQoS feature (untrusted by default) on routers

  • console> (enable) set qos autoqos       #turn on global QoS settings in CatOS

  • console> (enable) set port qos <mod/port> autoqos trust [cos|dscp] #CatOS specific interface configuration

  • console> (enable) set port qos <mod/port> autoqos voip [ciscosoftphone|ciscoipphone]         #When phones are attached

  • switch(config-if)# auto qos voip trust         #uplink interface connected to a trusted switch or router

  • switch(config-if)# auto qos voip cisco-phone         #enables a trusted boundary which uses CDP to detect the IP phone

  • #show auto qos [interface ]     # displays the interface configuration, policy-maps, class-maps and ACLs created

  • #show policy-map interface [interface]

  • switch# show mls qos interface            #multiple options exist for this one!

  • switch# show mls qos maps            #multiple options exist for this one! – used to generate an internal DSCP value


  • Automatically creates ACL that match voice and call control packets
  • Gives a policy that give high priority for VoIP packets (configures LLQ)
  • Configures the router to generate SNMP events for abnormal behaviour (too many voice packets dropped etc)
  • Works out what tools to enable based on interface types and speeds etc

You can reduce the time required to deploy QoS features for converged IP telephany and data networks

AutoQoS lends itself to tuning all generated parameters and configurations

When setup on a Catalyst platform AutoQos can be configured to trust all incoming COS or COS if they are coming from Cisco IP phone (using CDPv2). Therefore must have it enabled on the switch.

CEF must be enabled at the interface or ATM PVC due to the requirement of NBAR. It cannot be enabled if a QoS policy is already applied to the interface. It is important to ensure the bandwidth statement is correct on the interface and if the link speed is below 768 kbps and IP address must be configured (this will be used for the multilink config that is generated).