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Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
OL-4266-08
Chapter 41 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 41-1
lists the QoS features supported on the different versions of PFCs and DFCs.
Table 41-1
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