16
The following section briefly introduces these QoS techniques.
All QoS techniques in this document are based on the DiffServ model.
Deploying QoS in a network
Figure 2 Position of the QoS techniques in a network
As shown in
, traffic classification, traffic shaping, traffic policing, congestion management,
and congestion avoidance mainly implement the following functions:
•
Traffic
classification
—Uses match criteria to assign packets with the same characteristics to
a traffic class. Based on traffic classes, you can provide differentiated services.
•
Traffic
policing
—Polices flows and imposes penalties to prevent aggressive use of network
resources. You can apply traffic policing to both incoming and outgoing traffic of a port.
•
Traffic
shaping
—Adapts the output rate of traffic to the network resources available on the
downstream device to eliminate packet drops. Traffic shaping usually applies to the outgoing
traffic of a port.
•
Congestion
management
—Provides a resource scheduling policy to determine the packet
forwarding sequence when congestion occurs. Congestion management usually applies to the
outgoing traffic of a port.
•
Congestion
avoidance
—Monitors the network resource usage. It is usually applied to the
outgoing traffic of a port. When congestion worsens, congestion avoidance reduces the queue
length by dropping packets.
QoS processing flow in a device
briefly describes how the QoS module processes traffic.
1.
Traffic classifier identifies and classifies traffic for subsequent QoS actions.
2.
The QoS module takes various QoS actions on classified traffic as configured, depending on
the traffic processing phase and network status. For example, you can configure the QoS
module to perform the following operations:
{
Traffic policing for incoming traffic.
{
Traffic shaping for outgoing traffic.
{
Congestion avoidance before congestion occurs.
{
Congestion management when congestion occurs.
Summary of Contents for FlexFabric 5940 Series
Page 23: ...17 Figure 3 QoS processing flow ...
Page 84: ...78 Figure 26 MPLS label structure ...
Page 91: ...85 Switch burst mode enable ...
