QPPB can only classify and mark inbound packets

BGP is an interdomain routing protocol that exchanges reachability information with other BGP systems. The QoS policy propagation via the BGP feature allows classifying packets based on access lists, BGP community lists, and BGP AS paths.

The supported classification policies include IP precedence setting and the ability to tag the packet with a QoS class identifier internal to the router. After a packet has been classified, you can use other QoS features such as policing, WRED, and traffic shaping to specify and enforce business policies to fit the business model.

The QPPB feature has these enhancements:

■ QoS group ID: An internal QoS group ID can be set that can be used later to perform policing or weighted fair queuing (WFQ) based on the QoS group ID.

■ Source and destination address lookup: Specify whether the IP precedence level or QoS group ID is obtained from the source (input) address or destination (output) address entry in the route table.

BGP Marking

Propagate the CoS by encoding it into BGP attributes:

- BGP communities

- AS paths

- IP prefixes

- Any other BGP attribute

Translate the selected BGP attribute into either:

- IP precedence

- QoS group

Enable CEF and packet marking on interfaces

Propagate the CoS by encoding it into BGP attributes:

- BGP communities

- AS paths

- IP prefixes

- Any other BGP attribute

Translate the selected BGP attribute into either:

- IP precedence

- QoS group

Enable CEF and packet marking on interfaces

The figure shows three elements used on inbound packets to support QPPB operation.

■ Propagate the class of service (CoS) by encoding a value based on the following BGP attributes:

— BGP communities

— Any other BGP attribute

■ Translate the selected BGP attribute into either:

— IP precedence

■ Enable CEF and packet marking on interfaces.

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