Design Reference
Table Of Contents
- Contents
- Chapter 1: Introduction
- Chapter 2: New in this release
- Chapter 3: Network design fundamentals
- Chapter 4: Hardware fundamentals and guidelines
- Chapter 5: Optical routing design
- Chapter 6: Platform redundancy
- Chapter 7: Link redundancy
- Chapter 8: Layer 2 loop prevention
- Chapter 9: Spanning tree
- Chapter 10: Layer 3 network design
- Chapter 11: SPBM design guidelines
- Chapter 12: IP multicast network design
- Multicast and VRF-lite
- Multicast and MultiLink Trunking considerations
- Multicast scalability design rules
- IP multicast address range restrictions
- Multicast MAC address mapping considerations
- Dynamic multicast configuration changes
- IGMPv3 backward compatibility
- IGMP Layer 2 Querier
- TTL in IP multicast packets
- Multicast MAC filtering
- Guidelines for multicast access policies
- Multicast for multimedia
- Chapter 13: System and network stability and security
- Chapter 14: QoS design guidelines
- Chapter 15: Layer 1, 2, and 3 design examples
- Chapter 16: Software scaling capabilities
- Chapter 17: Supported standards, RFCs, and MIBs
- Glossary
Chapter 14: QoS design guidelines
This section provides design guidelines to provide Quality of Service (QoS) to user traffic on the
network.
For more information about fundamental QoS mechanisms, and how to configure QoS, see Avaya Virtual
Services Platform 4000 Configuration — QoS and IP Filtering, NN46251-502.
QoS mechanisms
Virtual Services Platform 4000 has a solid, well-defined architecture to handle QoS in an
efficient and effective manner. The following sections briefly describe several QoS
mechanisms that the platform uses.
QoS classification and mapping
Virtual Services Platform 4000 provides a hardware-based QoS 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.
You can configure ingress interfaces in one of two ways. In the first type of configuration, the
interface does not classify traffic, but it forwards the traffic based on the packet markings. This
mode of operation applies to trusted interfaces (core port mode) because the DSCP or 802.1p
field is trusted to be correct, and the edge switch performs the mapping without
classification.
In the second type of configuration, the interface classifies traffic as it enters the port, and
marks the packet for further treatment as it traverses Virtual Services Platform 4000 network.
This mode of operation applies to untrusted interfaces (access port mode) because the DSCP
or 802.1p field is not trusted to be correct.
Virtual Services Platform 4000 assigns an internal QoS level to each packet that enters a
port.
The Avaya QoS strategy simplifies QoS implementation by providing a mapping of various
traffic types and categories to a Class of Service. These service classes are termed Avaya
Service Classes (ASC). The following table provides a summary of the mappings and their
typical traffic types.
Table 13: Traffic categories and ASC mappings
Traffic category
Application example ASC
Network Control Alarms and heartbeats Critical
Routing table updates Network
Network Design Reference for Avaya VSP 4000 February 2014 129