Chapter 1 Qos Configuration; Overview; Introduction To Qos; Traditional Packet Forwarding Services - H3C S5100-SI Series Operation Manual

Chapter 1 QoS Configuration

When configuring QoS, go to these sections for information you are interested in:

Overview

QoS Features Supported by the S5100 Series Ethernet Switches
Introduction to QoS Features
QoS Configuration
QoS Configuration Examples
1.1 Overview

1.1.1 Introduction to QoS

Quality of Service (QoS) is a concept concerning service demand and supply. It reflects
the ability to meet customer needs. Generally, QoS focuses on improving services
under certain conditions rather than grading services precisely.
In an internet, QoS evaluates the ability of the network to forward packets of different
services. The evaluation can be based on different criteria because the network may
provide various services. Generally, QoS refers to the ability to provide improved
service by solving the core issues such as delay, jitter, and packet loss ratio in the
packet forwarding process.

1.1.2 Traditional Packet Forwarding Services

On traditional IP networks, devices treat all packets equally and handle them using the
first in first out (FIFO) policy. All packets share the resources of the network and
devices. How many resources the packets can obtain completely depends on the time
they arrive. This service is called best-effort. It delivers packets to their destinations as
possibly as it can, without any guarantee for delay, jitter, packet loss ratio, reliability and
so on.
This service policy is only suitable for applications insensitive to bandwidth and delay,
such as WWW, e-mail, and FTP.

1.1.3 New Requirements from Emerging Applications

The Internet has been growing along with the fast development of networking
technologies. More and more people use the Internet to transmit data, share video and
do a lot of other things.
Besides traditional applications such as WWW, e-mail and FTP, network users are
experiencing new services, such as tele-education, telemedicine, video telephone,
videoconference and Video-on-Demand (VoD). Enterprise users expect to connect
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