Specifications

White Paper

Figure 13. WS-X6716.10GE Linecard

3.4 Catalyst 6500 QoS Hardware Summary

The hardware components that perform the above QoS functions in the Catalyst 6500 are detailed in the table

below:

Table 12. QoS functions in a Catalyst 6500

QoS Process Catalyst 6500 Component that performs function

Input Scheduling Performed by port ASIC’s on linecard

L2 only with or without the PFC

Ingress Trust Performed by port ASIC’s on linecard

Ingress Congestion Management Performed by port ASIC’s on linecard

Ingress Classification Performed by PFC

Egress Classification Performed by PFC

Ingress Policing Performed by PFC via L3 Forwarding Engine

Egress Policing Performed by PFC via L3 Forwarding Engine

Packet Re-write Performed by port ASIC’s on linecard

Output Congestion Management Performed by port ASIC’s on linecard

Output Scheduling Performed by port ASIC’s on linecard

4. Catalyst 6500 Software support for QoS

The Catalyst 6500 supports three operating systems. The original software platform that shipped with the Catalyst

6500 was Catalyst OS (or more commonly referred to as CatOS) and this was derived from the code base used on

the Catalyst 5000 platform. Cisco introduced Cisco IOS (previously known as Native IOS) at a later date, and this

uses a code base derived from the Cisco Router IOS. More recently Cisco introduced a new version of its IOS OS

called IOS with software modularity; with this new OS the IOS processes are modularized to improve system

availability and resiliency. All three OS platforms (CatOS, Cisco IOS and IOS with software modularity) implement

software support to enable the QoS hardware features on the Catalyst 6500 platform. There is no difference in the

QoS capabilities of the Catalyst 6500 when running any OS platform. The QoS differences between the OS

platforms lie in the configuration options used to activate various QoS features.

In subsequent sections when explaining the configuration of QoS, this paper will use configuration examples from

IOS platform only.