Cisco 7609 User Manual

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Cisco 7600 Series Router Cisco IOS Software Configuration Guide—12.1E
78-14064-04
Chapter 32 Configuring PFC QoS
Understanding How PFC QoS Works
PFC QoS Feature Flowcharts
Figure 32-1 show how traffic flows through the components that support PFC QoS features.
Figure 32-1 Traffic Flow Through PFC QoS Features with PFC2
Note PFC QoS supports traffic from OSMs with Release 12.1(11a)E and later.
Figure 32-2 Traffic Flow Through PFC QoS Features with PFC
Note • The PFC can provide Layer 3 switching for FlexWAN traffic but does not provide PFC QoS for
FlexWAN traffic.
• PFC QoS does not change the ToS byte in FlexWAN ingress traffic.
• Traffic that is Layer 3-switched does not go through the MSFC and retains the Layer 2 CoS value
assigned by the PFC.
Figure 32-3 through Figure 32-8 show how the PFC QoS features are implemented on the router
components.
Transmit
frame
Ethernet
egress
port
Policy Feature Card 2
(PFC2)
QoS features
Multilayer Switch
Feature Card 2
(MSFC2)
Transmit
OSM traffic
OSM
egress
port
68833
CoS = IP precedence
for all traffic
(not configurable)
OSM traffic
enters switch
OSM
ingress
port
OSM
ingress QoS
features
OSM
egress QoS
features
CoS = 0 for all ATM and POS traffic
(not configurable)
FlexWAN
interfaces
Frame enters
switch
Ethernet
LAN
ingress port
Frame enters
switch
Transmit
frame
Ethernet
ingress
port
Ethernet
egress
port
Multilayer Switch
Feature Card (MSFC)
Policy Feature
Card (PFC)
68003
CoS = 0 for all traffic
(not configurable)
FlexWAN
interfaces

Cisco 7609 Specifications

General

Brand	Cisco
Model	7609
Category	Network Router
Language	English