Quick Reference Guide

Reference Manual for the Model FVM318 Cable/DSL ProSafe Wireless VPN Security Firewall
B-18 Network, Routing, Firewall, and Wireless Basics
Note: The AP and the client adapters can have different default WEP Keys as long as the keys are
in the same order. In other words, the AP can use WEP key 2 as its default key to transmit while a
client adapter can use WEP key 3 as its default key to transmit. The two devices will communicate
as long as the AP’s WEP key 2 is the same as the client’s WEP key 2 and the AP’s WEP key 3 is
the same as the client’s WEP key 3.
Wireless Channel Selection
IEEE 802.11 wireless nodes communicate with each other using radio frequency signals in the
ISM (Industrial, Scientific, and Medical) band between 2.4 GHz and 2.5 GHz. Neighboring
channels are 5 MHz apart. However, due to spread spectrum effect of the signals, a node sending
signals using a particular channel will utilize frequency spectrum 12.5 MHz above and below the
center channel frequency. As a result, two separate wireless networks using neighboring channels
(for example, channel 1 and channel 2) in the same general vicinity will interfere with each other.
Applying two channels that allow the maximum channel separation will decrease the amount of
channel cross-talk, and provide a noticeable performance increase over networks with minimal
channel separation.
The radio frequency channels used are listed in Table 8-1:
Table 8-1. 802.11 Radio Frequency Channels
Channel Center Frequency Frequency Spread
1 2412 MHz 2399.5 MHz - 2424.5 MHz
2 2417 MHz 2404.5 MHz - 2429.5 MHz
3 2422 MHz 2409.5 MHz - 2434.5 MHz
4 2427 MHz 2414.5 MHz - 2439.5 MHz
5 2432 MHz 2419.5 MHz - 2444.5 MHz
6 2437 MHz 2424.5 MHz - 2449.5 MHz
7 2442 MHz 2429.5 MHz - 2454.5 MHz
8 2447 MHz 2434.5 MHz - 2459.5 MHz
9 2452 MHz 2439.5 MHz - 2464.5 MHz
10 2457 MHz 2444.5 MHz - 2469.5 MHz
11 2462 MHz 2449.5 MHz - 2474.5 MHz
12 2467 MHz 2454.5 MHz - 2479.5 MHz
13 2472 MHz 2459.5 MHz - 2484.5 MHz