Huawei quidway s7700 - Introduction to Class-Based Qos; Class-Based Qos Features Supported by the S7700

1.1 Introduction to 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 S7700
The S7700 supports simple traffic classification, complex traffic classification, and priority
mapping.
Simple Traffic Classification
On the S7700, you can perform simple traffic classification for packets based on the mappings
between priorities of packets and Per-Hop Behaviors (PHBs) defined in a Differentiated Services
(DiffServ) domain. If packets come from an upstream device, the S7700 binds a DiffServ domain
to the inbound interface. In the DiffServ domain, the S7700 maps priorities of packets to PHBs
and colors. On the S7700, congestion management is performed for packets based on PHBs of
packets and congestion avoidance is performed for packets based on colors of packets. If packets
are sent to a downstream device, the S7700 binds a DiffServ domain to the outbound interface.
In the DiffServ domain, the S7700 maps PHBs and colors of packets to priorities so that the
downstream device provides QoS services based on priorities of packets.
Simple traffic classification is based on:
l 802.1p priority in VLAN packets
l DiffServ Code Point (DSCP) priority in IP packets
Complex Traffic Classification
Complex traffic classification is performed based on Layer 2 or Layer 3 information in packets
or by using access control lists (ACLs). You can bind a traffic classifier to a traffic behavior to
process packets matching the traffic classifier.
A traffic behavior is related to the current phase of packets and the current load of a network.
For example, when packets enter a node, the S7700 performs traffic policing and access control
for the packets based on the committed information rate (CIR). When packets leave a node, the
S7700 shapes the traffic of packets and re-marks the priorities of packets.
Complex traffic classification is based on:
l 802.1p priority in VLAN packets
l VLAN ID in packets
l 802.1p priority in CVLAN packets
l CVLAN ID in CVLAN packets
l Double tags of VLAN packets
l Inbound or outbound interface
l IP precedence in IP packets
l DSCP priority in IP packets
Quidway S7700 Smart Routing Switch
Configuration Guide - QoS 1 Class-based QoS Configuration
Issue 01 (2011-07-15) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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