Cisco Systems OL-4266-08 manual 42-10, Ingress PFC QoS

Models: OL-4266-08

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Chapter 42 Configuring PFC QoS

Understanding How PFC QoS Works

Figure 42-6shows how traffic flows through the QoS features on the PFC and DFCs.

Figure 42-6 QoS Features on the PFC and DFCs

Ingress PFC QoS

For trust CoS traffic:

CoS Map Initial

(Received or Port)Internal

DSCP

For trust DSCP traffic:

 

 

Received

Initial

Internal

 

 

 

 

DSCP

 

DSCP

 

 

For trust IP precedence traffic:

Received IP

 

 

Initial

Map

 

Internal

 

 

 

 

 

Precedence

 

 

 

 

DSCP

 

 

 

 

For untrusted traffic or for any traffic if ignore port trust is configured

When ignore port trust is not configured

Initial Internal DSCP=0

When ignore port trust is configured, received DSCP (if any) is initial internal DSCP, otherwise port CoS is mapped to initial internal DSCP

Policy map

Policer

Marker

(Optional)

Policy map

Policer

Marker

(Optional)

Policy map

Policer

Marker

(Optional)

Policy map

Policer

Marker

(Optional)

Traffic Forwarding

MSFC routing

or

PFC Layer 3

switching

or

PFC Layer 2

switching

 

 

Egress PFC QoS

 

 

 

 

 

 

 

 

 

Egress

 

 

Policy map

 

 

 

 

DSCP

 

 

 

Policer

 

Final

 

Mutation

 

Egress

 

 

Internal

 

 

Map

 

 

 

Marker

 

 

 

 

 

DSCP

 

 

DSCP

 

 

 

 

 

(Optional;

(only on PFC3)

 

 

 

 

 

 

 

 

 

 

only

Map

 

 

 

 

 

Egress CoS

with PFC 3)

 

 

 

 

 

 

 

 

(LAN ports only)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

154644

Note The DSCP transparency feature makes writing the egress DSCP value into the Layer 3 ToS byte optional.

 

Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX

42-10

OL-4266-08

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Cisco Systems OL-4266-08 manual 42-10, Ingress PFC QoS