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TCP/IP Tutorial and Technical Overview - IBM Redbooks

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10.4 WiMax<br />

confidentiality functions of WPA into one protocol. CCMP is considered fully<br />

secure.<br />

Also known as WirelessMAN, the Worldwide Interoperability for Microwave<br />

Access (WiMAX) is a digital communications system defined by the IEEE<br />

st<strong>and</strong>ard 802.16 (most recently approved in 2004). Much like the Wi-Fi Wireless<br />

Alliance, WiMAX is monitored by the WiMAX forum, which strives to ensure<br />

product compliance with the 802.16 st<strong>and</strong>ard <strong>and</strong> device interoperability.<br />

Similar to the client/server model (see 11.1.1, “The client/server model” on<br />

page 408), WiMAX uses the notion of subscriber stations <strong>and</strong> base stations.<br />

Base stations provide the wireless access <strong>and</strong> provide the same functions as the<br />

WAPs. Subscriber stations are the clients using the wireless access provided by<br />

the base station.<br />

802.16 family of st<strong>and</strong>ards<br />

There are several specifications in the 802.16 family of st<strong>and</strong>ards:<br />

802.16 This applies to enabling last mile wireless broadb<strong>and</strong> access <strong>and</strong> can<br />

be used as an alternative to DSL <strong>and</strong> cable. This specification is also<br />

known as WirelessMAN.<br />

802.16a This specification addresses issues of radio spectrum use. It<br />

specifies added support for the 2 to 11 GHz range that provides<br />

support for low latency applications such as video <strong>and</strong> voice. It<br />

enables the provision of broadb<strong>and</strong> connectivity without the<br />

requirement of direct line of sight (LOS) between the subscriber<br />

terminals <strong>and</strong> the base station (BTS).<br />

802.16b This extends 802.16 by increasing the spectrum to 5 <strong>and</strong> 6 GHz. This<br />

provides quality of service (QoS) for voice <strong>and</strong> video services.<br />

802.16c This extends 802.16 by representing the 10 to 66 GHz range. This<br />

extension also addresses issues such as interoperability,<br />

performance evaluation, testing, system profiling, <strong>and</strong> performance<br />

evaluation.<br />

802.16e Also known as Mobile WiMaX. This extends <strong>and</strong> improves the<br />

modulation schemes described in the original/fixed WiMax st<strong>and</strong>ard.<br />

This allows for fixed wireless <strong>and</strong> mobile NLOS applications by<br />

improving upon the Orthogonal Frequency Division Multiple Access<br />

(OFDMA). This should not be confused with 802.20.<br />

400 <strong>TCP</strong>/<strong>IP</strong> <strong>Tutorial</strong> <strong>and</strong> <strong>Technical</strong> <strong>Overview</strong>

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