Cisco Systems EA6500 Manual De Usuario

This chapter describes how to configure quality of service (QoS) as implemented on the policy feature 
card (PFC) on the Catalyst 6500 series switches.

For complete syntax and usage information for the commands used in this publication, refer to the 
Catalyst 6500 Series Switch Cisco IOS Command Reference publication.

This chapter contains these sections:

With Release 12.1(13)E and later releases and with an MSFC2, you can configure Network-Based 
Application Recognition (NBAR) on Layer 3 interfaces instead of using PFC QoS.

All ingress and egress traffic on an interface that is configured with NBAR is processed in software 
on the MSFC2.

The PFC2 provides hardware support for input ACLs on ports where you configure NBAR.

When PFC QoS is enabled, the traffic through ports where you configure NBAR passes through the 
ingress and egress queues and drop thresholds. When PFC QoS is enabled, the MSFC2 sets egress 
CoS equal to egress IP precedence.

After passing through an ingress queue, all traffic is processed in software on the MSFC2 on 
interfaces where you configure NBAR.

To configure NBAR, refer to this publication:

Typically, networks operate on a best-effort delivery basis, which means that all traffic has equal priority 
and an equal chance of being delivered in a timely manner. When congestion occurs, all traffic has an 
equal chance of being dropped.