Chapter 12
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 12-1 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 three schedule modes: SP, WRR and SP+WRR.
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.
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