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<concept id="GUID-375C5C68-67C0-5414-9D41-DDD76692DC81" xml:lang="en"><title>Traffic

Classes</title><shortdesc> Traffic Classes are used to categorise the types of communication

carried by a Universal Mobile Telephone System (UMTS).</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>When implementing QoS within a UMTS you can divide the types of traffic

that can be carried into classes based on their characteristics. Also, with

the bandwidth, latency, and reliability there are some characteristics that

the network needs to adapt if it has to carry the traffic effectively. Two

of these are whether the traffic comes intermittently and whether the upstream

and downstream traffic characteristics are symmetric or asymmetric. </p>

<p>The traffic classes carried by a UMTS are divided into the following categories: </p>

<ul>

<li id="GUID-6FA20E30-9FB2-5E94-A927-5761E2E102B8"><p> <b>Conversational Traffic

Class (Voice telephony)</b> - This is characterized by a fixed, and relatively

small bandwidth with a small latency and comparatively less number of transmission

errors. The upstream and downstream data rates are symmetrical. </p> </li>

<li id="GUID-06BD9213-2841-5325-AC89-66F0FEAF6ED4"><p> <b>Streaming Traffic

Class</b> - This class of traffic is continuous data such as streaming video.

Some errors can be tolerated for example, dropped lines in a single video

frame. The data rates are high and generally asymmetrical. </p> </li>

<li id="GUID-A2708944-1C45-5C5C-A62D-8BB41B3D9C22"><p> <b>Interactive Traffic

Class</b> - This class of traffic handles user request or server response

traffic such as web browsing. It is medium bandwidth, must be reliable and

is intermittent asymmetric data. Unlike the other classes different priorities

can be attached to interactive traffic. </p> </li>

<li id="GUID-DD1AC5DC-BE61-5C7D-A91E-164B813AF9FA"><p> <b>Background Traffic

Class</b> - This traffic is low volume occasional traffic such as an Email.

A reasonable delay is acceptable to the user but reliability must be high. </p> </li>

</ul>

<p>The following table illustrates the characteristics of these classes: </p>

<table id="GUID-A640819E-C63F-583B-9C73-6252BE86D789">

<tgroup cols="6"><colspec colname="col0"/><colspec colname="col1"/><colspec colname="col2"/><colspec colname="col3"/><colspec colname="col4"/><colspec colname="col5"/>

<thead>

<row>

<entry>Traffic Class</entry>

<entry>Acceptable Bandwidth</entry>

<entry>Acceptable Latency</entry>

<entry>Acceptable Reliability</entry>

<entry>Intermittent Data</entry>

<entry>Asymmetric</entry>

</row>

</thead>

<tbody>

<row>

<entry><p>Conversational </p> </entry>

<entry><p>Low </p> </entry>

<entry><p>Low </p> </entry>

<entry><p>Low </p> </entry>

<entry><p>No </p> </entry>

<entry><p>No </p> </entry>

</row>

<row>

<entry><p>Streaming </p> </entry>

<entry><p>High </p> </entry>

<entry><p>Medium </p> </entry>

<entry><p>Medium </p> </entry>

<entry><p>No </p> </entry>

<entry><p>Yes </p> </entry>

</row>

<row>

<entry><p>Interactive </p> </entry>

<entry><p>Medium </p> </entry>

<entry><p>Medium </p> </entry>

<entry><p>High </p> </entry>

<entry><p>Yes </p> </entry>

<entry><p>Yes </p> </entry>

</row>

<row>

<entry><p>Background </p> </entry>

<entry><p>Low </p> </entry>

<entry><p>High </p> </entry>

<entry><p>High </p> </entry>

<entry><p>Yes </p> </entry>

<entry><p>Yes </p> </entry>

</row>

</tbody>

</tgroup>