Released in Cisco IOS Release 12215T

The NBAR feature has these two components:

■ One component monitors applications traversing a network.

■ The other component classifies traffic by protocol.

In order to monitor applications traversing a network, protocol discovery must be enabled. The ability to classify traffic by protocol using NBAR and then to apply QoS to the classified traffic is configured using the MQC.

Use the ip nbar protocol-discovery command to configure NBAR to keep traffic statistics for all protocols known to NBAR. Protocol discovery provides an easy way to discover application protocols supported by NBAR that are transiting an interface, so that QoS policies can be developed and applied. The protocol discovery feature discovers any protocol traffic. Protocol discovery can be used to monitor both input and output traffic and can be applied with or without a service policy enabled.

Note You must enable CEF before you configure NBAR. For more information on CEF, refer to

Cisco Express Forwarding Overview at

http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/switch_c/xcprt2/xc dcef.htm.

Use the show ip nbar protocol-discovery command to display statistics gathered by the NBAR protocol discovery feature. This command, by default, displays statistics for all interfaces on which protocol discovery is currently enabled. The default output of this command includes, in this order: input bit rate (bps), input byte count, input packet count, and protocol name. Output statistics include packet count, byte count, and the output bit rate in bps.

You can use protocol discovery to monitor both input and output traffic and apply it with or without a service policy enabled. NBAR protocol discovery gathers statistics for packets switched to output interfaces. These statistics are not necessarily for packets that exited the router on the output interfaces, because packets might have been dropped after switching for various reasons (policing at the output interface, access lists, or queue drops). The example displays partial output of the show ip nbar protocol-discovery command for an Ethernet interface.

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