Traffic Classification; Chapter 1 Qos Configuration - Huawei Quidway S3900 Series Operation Manual

Operation Manual - QoS&QoS Profile
Quidway S3900 Series Ethernet Switches-Release 1510

Chapter 1 QoS Configuration

1.1 Overview
QoS (Quality of Service) is a concept generally existing in occasions with service
supply and demand. It evaluates the ability to meet the need of the customers in
service. Generally, the evaluation is not to grade precisely. Its purpose is to analyze the
conditions when the service is the best and the conditions when the service still needs
improvement and then to make improvements in the specified aspects.
In internet, QoS evaluates the ability of the network to deliver packets. The evaluation
on QoS can be based on different aspects because the network provides various
services. Generally speaking, QoS is the evaluation on the service ability to support the
core requirements such as delay, delay variation and packet loss ratio in the packet
delivery.
1.1.1 Traffic
Traffic means service traffic, that is, all the packets passing the switch.

1.1.2 Traffic Classification

Traffic classification means to identify packets conforming to certain characters
according to certain rules.
A classification rule is a filter rule configured to meet your management requirements. It
can be very simple. For example, you can use a classification rule to identify traffic with
different priorities according to the ToS field in the IP packet header. It can be very
complicated too. For example, you can use a classification rule to identify the packets
according to the combination of link layer (Layer 2), network layer (Layer 3) and
transport layer (Layer 4) information including MAC addresses, IP protocols, source
addresses, destination addresses, the port numbers of applications and so on.
Classification is generally based on the information in the packet header and rarely
based on the packet content.
1.1.3 Precedence
1) IP precedence, ToS precedence and DSCP precedence
Huawei Technologies Proprietary
1-1
Chapter 1 QoS Configuration