Introduction To Class-Based Qos; Class-Based Qos Features Supported By The S9300 - Huawei Quidway S9300 Configuration Manual

1 Class-based QoS Configuration

1.1 Introduction to Class-based QoS

This section describes the basic concepts of the Class-based QoS.
Class-based QoS is used to classify packets sharing common features into one class and provide
the same QoS service for traffic of the same type by matching packets with certain rules. In this
manner, differentiated services are provided.

1.2 Class-based QoS Features Supported by the S9300

This section describes the Class-based QoS features supported by the S9300.
Simple Traffic Classification
On the S9300, you can perform simple traffic classification for packets according to the mapping
between priorities of packets and Per-Hop Behaviors (PHBs) defined in a Differentiated Services
(DiffServ) domain. If packets come from an upstream device, the S9300 binds a DiffServ domain
to the incoming interface. In the DiffServ domain, the S9300 map priorities of the packets to
PHBs and colors. On the S9300, congestion management is performed for packets according to
PHBs of packets and congestion avoidance is performed for packets according to colors of
packets. If packets are sent to a downstream device, the S9300 binds a DiffServ domain to the
outgoing interface. In the DiffServ domain, the S9300 maps PHBs and colors of the packets to
priorities. Then, the downstream device provides QoS services according to the priorities of
packets.
Simple traffic classification is based on:
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Complex Traffic Classification
In addition to classification through a DiffServ domain, you can perform complex traffic
classification according to Layer 2 or Layer 3 information in packets or through access control
lists (ACLs). Then, you can bind a traffic classifier to a traffic behavior to process packets
matching the traffic classifier.
The traffic behavior adopted is related to the current phase of packets and the current load of a
network. For example, when packets enter a node, the S9300 performs traffic policing and access
control for the packets according to the committed information rate (CIR); when packets exit a
node, the S9300 performs traffic shaping and re-marking for the packets.
Complex traffic classification is based on:
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802.1p priority of packets in a VLAN
DiffServ Code Point (DSCP) priority of IP packets
EXP priority of MPLS packets
802.1p priority of packets in a VLAN
VLAN ID of packets
Double tags of packets in a VLAN
Incoming or outgoing interface
IP priority of IP packets
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Quidway S9300 Terabit Routing Switch
Configuration Guide - QoS
Issue 03 (2009-08-20)