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Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
OL-4266-08
Chapter 42 Configuring PFC QoS
Understanding How PFC QoS Works
Supported Policy Feature Cards
The policy feature card (PFC) is a daughter card that resides on the supervisor engine. The PFC provides
QoS in addition to other functionality. The following PFCs are supported on the Cisco 7600 series
routers:
• PFC2 on the Supervisor Engine 2
• PFC3A on the Supervisor Engine 720
• PFC3B on the Supervisor Engine 720 and Supervisor Engine 32
• PFC3BXL on the Supervisor Engine 720
Supported Distributed Forwarding Cards
The PFC sends a copy of the QoS policies to the distributed forwarding card (DFC) to provide local
support for the QoS policies, which enables the DFCs to support the same QoS features that the PFC
supports.
The following DFCs are supported on the Cisco 7600 series routers:
• WS-F6K-DFC, for use on dCEF256 and CEF256 modules with a Supervisor Engine 2.
• WS-F6K-DFC3A, WS-F6K-DFC3B, WS-F6K-DFC3BXL, for use on dCEF256 and CEF256
modules with a Supervisor Engine 720.
• WS-F6700-DFC3A, WS-F6700-DFC3B, WS-F6700-DFC3BXL, for use on CEF720 modules with
a Supervisor Engine 720.
PFC and DFC QoS Feature List and Flowchart
Table 42-1 lists the QoS features supported on the different versions of PFCs and DFCs.
Table 42-1 QoS Features Supported on PFCs and DFCs
Feature PFC2/DFC PFC3A/DFC3A PFC3B/DFC3B PFC3BXL/DFC3BXL
Support for DFCs Yes Yes Yes Yes
Flow granularity Full flow Source
Destination
Source
Destination
Source
Destination
QoS ACLs IP, IPX, MAC IP, MAC IP, MAC IP, MAC
DSCP transparency
Note Enabling DSCP transparency disables
egress ToS rewrite.
No Optional Optional Optional
Egress ToS rewrite Mandatory Optional Optional Optional
Policing:
Ingress aggregate policers Yes Yes Yes Yes
Egress aggregate policers No Yes Yes Yes
Number of aggregate policers 1022 1022 1022 1022
Microflow policers 64 rates 64 rates 64 rates 64 rates
Number of flows per Microflow policer 32,000 64,000 110,000 240,000
Unit of measure for policer statistics Packets Bytes Bytes Bytes
Basis of policer operation Layer 3 length Layer 2 length Layer 2 length Layer 2 length