Cisco Cisco IOS Software Release 12.2(14)S

NBAR includes a Protocol Discovery feature that provides an easy way to discover application 
protocols that are transversing an interface. The Protocol Discovery feature discovers any protocol 
traffic supported by NBAR. Protocol Discovery maintains the following per-protocol statistics for 
enabled interfaces: total number of input and output packets and bytes, and input and output bit rates. 
The Protocol Discovery feature captures key statistics associated with each protocol in a network that 
can be used to define traffic classes and QoS policies for each traffic class.

Identifying and classifying network traffic is an important first step in implementing QoS. A network 
administrator can more effectively implement QoS in a networking environment after identifying the 
amount and the variety of applications and protocols running on a network.

NBAR gives network administrators the ability to see the variety of protocols and the amount of traffic 
generated by each protocol. After gathering this information, NBAR allows users to implement classes 
of traffic. These classes of traffic can then be used to provide different levels of service for network 
traffic, therefore allowing better network management by providing the right level of network resources 
for network traffic.

The following section provides information on several topics that could be useful to individuals 
configuring NBAR in their networks. The following topics are covered in this section:

When NBAR is enabled on a Catalyst 6000 without a FlexWAN module interface, all traffic flows 
entering or leaving the NBAR-enabled interface will be processed in software on the MSFC2.

The following other restrictions should also be noted when running NBAR:

NBAR can only be implemented on an MSFC2 with Supervisor Engine 1 or Supervisor Engine 2.