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640-802 CCNA Study Guide - Elktech.org

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C. 172.16.5.1<br />

D. 192.168.5.3<br />

Cisco <strong>640</strong>-<strong>802</strong> Exam<br />

Answer: C<br />

Explanation:<br />

QUESTION NO: 337<br />

Which spread spectrum technology does the <strong>802</strong>.11b standard define for operation?<br />

A. IR<br />

B. DSSS<br />

C. FHSS<br />

D. DSSS and FHSS<br />

E. IR, FHSS, and DSSS<br />

Answer: B<br />

Explanation:<br />

This question is to examine the knowledge point about the wireless.<br />

The differences of performance and capacity of the Wireless local area network mainly depends<br />

on the applied FHSS or DSSS, as well as the applied modulation type, to achieve. Up to now, if<br />

we compare the parameters of existing products in detail, we can see that the DSSS technology<br />

shows relative advantage in the applications which require optimum reliability, while FHSS<br />

technology plays relative advantage in the applications which require low cost. In the selection of<br />

wireless products, we have to pay attention which spread-spectrum technology, DSSS or FHSS, is<br />

chosen by manufacturers. We must prudence the market positioning of end view products<br />

because they can solve the transmission capability and characteristic of the wireless LAN,<br />

including anti-interference ability, usable distance range, bandwidth size, and the data transfer<br />

size.<br />

Generally, DSSS uses the full bandwidth to transmit data to quicken its transmission speed, which<br />

means a greater potential to higher transmission frequency in the future. DSSS technology is<br />

applicable to a fixed environment, or to applications which have higher quality requirement,<br />

therefore, mostly applications, such as wireless plant, wireless hospital, network community,<br />

branch school networking, are applied to DSSS wireless technology products.FHSS is mostly<br />

used in fast-moving endpoint, for example, mobile phone applies FHSS technology in wireless<br />

transmission technology part. Due to the small FHSS transmission range, though under the same<br />

transmission environment, the required technology devices of FHSS is more than those of DSSS<br />

and the price of FHSS will probably be higher as a whole. As to the current business requirement,<br />

high-speed mobile endpoint applications are relatively less, while mostly pay attention to the<br />

transmission rate, as well as the stability of transmission. Therefore, the DSSS technology will be<br />

"Pass Any Exam. Any Time." - www.actualtests.com 233

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