Network Router User Manual

42-4
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
These figures provide more detail about the relationship between QoS and the router components:
• Figure 42-2, Traffic Flow and PFC QoS Features with PFC3
• Figure 42-3, Traffic Flow and PFC QoS Features with PFC2
• Figure 42-4, PFC QoS Features and Component Overview
Figure 42-2 shows traffic flow and PFC QoS features with a PFC3.
Figure 42-2 Traffic Flow and PFC QoS Features with PFC3
Figure 42-2 shows how traffic flows through the PFC QoS features with PFC3:
• Traffic can enter on any type of port and exit on any type of port.
• DFCs implement PFC QoS locally on switching modules.
• For FlexWAN module traffic:
– Ingress FlexWAN QoS features can be applied to FlexWAN ingress traffic.
– Ingress FlexWAN traffic can be Layer 3-switched by the PFC3 or routed in software by the MSFC.
– Egress PFC QoS is not applied to FlexWAN ingress traffic.
– Egress FlexWAN QoS can be applied to FlexWAN egress traffic.
• For LAN-port traffic:
– Ingress LAN-port QoS features can be applied to LAN-port ingress traffic.
– Ingress PFC QoS can be applied to LAN-port ingress traffic.
– Ingress LAN-port traffic can be Layer-2 or Layer-3 switched by the PFC3 or routed in software
by the MSFC.
– Egress PFC QoS and egress LAN-port QoS can be applied to LAN-port egress traffic.
• For OSM traffic:
– Ingress OSM-port QoS features can be applied to OSM-port ingress traffic.
– Ingress PFC3 QoS can be applied to OSM-port ingress traffic.
– Ingress OSM-port traffic can be Layer-3 switched by the PFC3 or routed in software by the MSFC.
– Egress PFC3 QoS and egress OSM-port QoS can be applied to OSM-port egress traffic.
Transmit
FlexWAN traffic
Multilayer Switch
Feature Card
(MSFC)
Transmit
OSM traffic
105757
FlexWAN traffic
enters switch
FlexWAN
ingress port and
QoS features
FlexWAN
egress port and
QoS features
OSM traffic
enters switch
OSM ingress
port and
QoS freatures
OSM egress
port and
QoS freatures
CoS = 0 for all ATM and POS traffic (not configurable)
CoS = IP precedence for all traffic
(not configurable)
Transmit
LAN traffic
LAN traffic
enters switch
LAN ingress
port and
QoS features
LAN egress
port and
QoS features
Ingress
PFC3
QoS
Egress
PFC3
QoS
PFC3
Layer 2 or 3
switching