Chapter 16: Qos Design Guidelines; Qos Mechanisms; Qos Classification And Mapping - Avaya 8800 Planning And Engineering, Network Design

Chapter 16: QoS design guidelines

This section provides design guidelines that you can use when you configure your network to
provide Quality of Service (QoS) to user traffic.
Quality of Service (QoS) is defined as the extent to which a service delivery meets user
expectations. In a QoS-aware network, a user can expect the network to meet certain performance
expectations. These performance expectations are usually specified in terms of service availability,
bandwidth, packet loss, packet delay (latency), and packet delay variation (jitter).
For more information about fundamental QoS mechanisms, and how to configure QoS, see Avaya
Ethernet Routing Switch 8800/8600 Configuration — QoS and IP Filtering for R and RS Modules,
NN46205-507.

QoS mechanisms

The Avaya Ethernet Routing Switch 8800/8600 has a solid, well-defined architecture to handle QoS
in an efficient and effective manner. Several QoS mechanisms used by the Ethernet Routing Switch
8800/8600 are briefly described in the sections that follow.
QoS mechanisms navigation
•

QoS classification and mapping

• QoS and queues
• QoS and filters
• Policing and shaping
QoS classification and mapping
The Avaya Ethernet Routing Switch 8800/8600 provides a hardware-based Quality of Service
platform through hardware packet classification. Packet classification is based on the examination of
the QoS fields within the Ethernet packet, primarily the DiffServ Codepoint (DSCP) and the 802.1p
fields. Unlike legacy routers that require CPU processing cycles for packet classification, which
degrades switch performance, the Ethernet Routing Switch 8800/8600 performs classification in
hardware at switching speeds.
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Planning and Engineering — Network Design
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