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<h1>TCP throughput optimisation for (E)GPRS</h1>

<p>This section includes some recommendations for the essential
settings of:</p>


<ul>
<li><p>BSS</p>
</li>
<li><p>HLR</p>
</li>
<li><p>Packet Core</p>
</li>
<li><p>MS-PC interface</p>
</li>
<li><p>FTP/HTTP server.</p>
</li>
</ul>


<p>These recommendations can be used to obtain the maximum throughput provided
by an EGPRS MS with up to 3 timeslots. Maximum throughput means that it is
limited mainly by the available link bandwidth of 59.2kbit/s per slot, excluding
the protocol overheads.</p>


<p>Most of the parameters are already optimised for high throughput,
but they have been specified in order to identify possible bottlenecks. The
purpose is not to design a new TCP stack implementation, but rather to define
the right TCP parameter values in order to get the best performance. The same
recommendations also apply to UDP transport in RLC ACK mode.</p>


<p>The User Plane of EGPRS includes some potential throughput
bottlenecks, which are illustrated in Figure <em>Protocol stack
for EGPRS User Plane with Terminal Equipment</em> and Figure <em>Protocol
stack for EGPRS User Plane</em>.</p>


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<img alt="urn:mars:dn03316841:1:en:global:cgm_fixed:data:data" border="0" src="NED?action=retrieve&amp;identifier=dn03316841&amp;edition=1&amp;language=en&amp;coverage=global&amp;encoding=gif&amp;component=data&amp;item=data" /><p class="figure-caption">Figure: Protocol stack for EGPRS User Plane with Terminal Equipment</p>
</div>


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<img alt="urn:mars:dn03316853:1:en:global:cgm_fixed:data:data" border="0" src="NED?action=retrieve&amp;identifier=dn03316853&amp;edition=1&amp;language=en&amp;coverage=global&amp;encoding=gif&amp;component=data&amp;item=data" /><p class="figure-caption">Figure: Protocol stack for EGPRS User Plane</p>
</div>


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<p>Table: Sub-areas for throughput optimisation</p>


<table border="1">
<thead>
<tr align="left" char="" charoff="50" valign="bottom">
<th colspan="1" rowspan="1" valign="top"><p>Sub-area</p>
</th>
<th colspan="1" rowspan="1" valign="top"><p>Chapter</p>
</th>
</tr>
</thead>
<tbody>
<tr align="left" char="" charoff="50" valign="top">
<td colspan="1" rowspan="1"><p>TCP/IP</p>
</td>
<td colspan="1" rowspan="1"><p>2</p>
</td>
</tr>
<tr align="left" char="" charoff="50" valign="top">
<td colspan="1" rowspan="1"><p>SNDCP/LLC</p>
</td>
<td colspan="1" rowspan="1"><p>3</p>
</td>
</tr>
<tr align="left" char="" charoff="50" valign="top">
<td colspan="1" rowspan="1"><p>RLC/MAC</p>
</td>
<td colspan="1" rowspan="1"><p>4</p>
</td>
</tr>
<tr align="left" char="" charoff="50" valign="top">
<td colspan="1" rowspan="1"><p>PPP/IrDA and PPP/USB</p>
</td>
<td colspan="1" rowspan="1"><p>6</p>
</td>
</tr>
</tbody>
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<p><a href="NED?action=retrieve&amp;identifier=dn03301829&amp;edition=4&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=ned_2#ned_2" onclick="sync(this);return true" shape="rect">TCP/IP and throughput optimisation for EGPRS</a></p>


<p><a href="NED?action=retrieve&amp;identifier=dn03301829&amp;edition=4&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=ned_5#ned_5" onclick="sync(this);return true" shape="rect">SNDCP/LLC and throughput optimisation for EGPRS</a></p>


<p><a href="NED?action=retrieve&amp;identifier=dn03301829&amp;edition=4&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=ned_6#ned_6" onclick="sync(this);return true" shape="rect">RLC/MAC and throughput optimisation for EGPRS</a></p>


<p><a href="NED?action=retrieve&amp;identifier=dn03301829&amp;edition=4&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=ned_7#ned_7" onclick="sync(this);return true" shape="rect">BSSGP and throughput optimisation for EGPRS</a></p>


<p><a href="NED?action=retrieve&amp;identifier=dn03301829&amp;edition=4&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=ned_8#ned_8" onclick="sync(this);return true" shape="rect">HLR and throughput optimisation for EGPRS</a></p>


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<div class="div">
<h2>Virus update or background data transfer</h2>

<p>Automatic virus updates or other background processes may
reduce the obtained throughput substantially. It is difficult to detect the
existence of such procedures without IP layer trace.</p>
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