Router Prerequisites

Router Prerequisites

Before configuring AutoQoS on a router, the following prerequisites must be met:

  • Cisco Express Forwarding (CEF) must be enabled on the interface where AutoQoS is to be enabled.

    - AutoQoS relies on NBAR for discovery, and NBAR needs CEF.

  • You cannot apply a QoS policy (service policy) to the interface prior to enabling AutoQoS on that interface.

  • You must configure the bandwidth on all interfaces and subinterfaces.

    - On slow links (768 kbps or lower), you must configure an IP address.

    - AutoQoS enables MLP on slow links and moves the IP address to the MLP virtual template.

  • For AutoQoS SNMP traps to work, you must have SNMP enabled on the router and specify the server address for SNMP traps destination.

    - The address must be reachable from the router.

    - The SNMP community string "AutoQoS" must have write permission.

  • By default, Cisco routers reserve up to 75 percent of the interface bandwidth for user-defined classes.

    - The remaining bandwidth is kept for the default class.

    - The entire remaining bandwidth is not guaranteed to the default class.

    - The default class and excess traffic from other bandwidth classes share this bandwidth proportionately.