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TCP/IP Tutorial and Technical Overview - IBM Redbooks

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Feature <strong>and</strong> performance-enhancing proxies<br />

The WAP model recommends the use of proxies to optimize the connection<br />

between the wireless clients <strong>and</strong> the Web (see Figure 18-2).<br />

Client<br />

WAP<br />

MicroBrowser<br />

(with WTA)<br />

EncodedRequest (URL)<br />

Encoded Response(Content)<br />

Content<br />

Figure 18-2 Feature <strong>and</strong> performance-enhancing proxy<br />

Proxy<br />

HTTP<br />

Proxy<br />

Feature<br />

Enhancements<br />

Application Server<br />

HTTP<br />

Server<br />

Content<br />

A variety of functions are then provided by the WAP proxy, including:<br />

Request URL<br />

Protocol gateway Translates requests from a wireless protocol stack (for<br />

example, the WAP 1.x stack—WSP, WTP, WTLS, <strong>and</strong><br />

WDP) to the WWW protocols (HTTP <strong>and</strong> <strong>TCP</strong>/<strong>IP</strong>). Also<br />

can perform DNS lookups for the URLs requested by the<br />

client.<br />

Content encoders <strong>and</strong> decoders<br />

Translates WAP content for better utilization of the<br />

underlying link, reducing the b<strong>and</strong>width use by different<br />

compression techniques.<br />

Chapter 18. Wireless Application Protocol 659

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