H3C H3C S5100-SI, Operation Manual, Page: 390 / 830

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QoS Configuration
When configuring QoS, go to these sections for information you are interested in:
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Overview
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QoS Features Supported by the S5100 Series Ethernet Switches
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Introduction to QoS Features
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QoS Configuration
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QoS Configuration Examples
Overview
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.
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.
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 their