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Chapter 9 QoS
QoS (Quality of Service) functions to provide different quality of service for various network
applications and requirements and optimize the bandwidth resource distribution so as to provide a
network service experience of a better quality.
QoS
This switch classifies the ingress packets, maps the packets to different priority queues and then
forwards the packets according to specified scheduling algorithms to implement QoS function.
Figure 9-1 QoS function
Traffic classification: Identifies packets conforming to certain characters according to certain
rules.
Map: The user can map the ingress packets to different priority queues based on the priority
modes. This switch implements three priority modes based on port, on 802.1P and on DSCP.
Queue scheduling algorithm: When the network is congested, the problem that many packets
compete for resources must be solved, usually in the way of queue scheduling. The switch
supports four schedule modes: SP, WRR, SP+WRR and Equ.
Priority Mode
This switch implements three priority modes based on port, on 802.1P and on DSCP. By default, the
priority mode based on port is enabled and the other two modes are optional.
1. Port Priority
Port priority is just a property of the port. After port priority is configured, the data stream will be
mapped to the egress queues according to the CoS of the port and the mapping relationship
between CoS and queues.
