Netgear CG814M ユーザーズマニュアル

B-12

Networks, Routing, and Firewall Basics

The CG814M Gateway conforms to the Institute of Electrical and Electronics Engineers (IEEE) 
802.11b standard for wireless LANs (WLANs). On an 802.11b wireless link, data is encoded using 
direct-sequence spread-spectrum (DSSS) technology and is transmitted in the unlicensed radio 
spectrum at 2.5GHz. The maximum data rate for the wireless link is 11 Mbps, but it will 
automatically back down from 11 Mbps to 5.5, 2, and 1 Mbps when the radio signal is weak or 
when interference is detected.

The 802.11b standard is also called Wireless Ethernet or Wi-Fi by the Wireless Ethernet 
Compatibility Alliance (WECA, see http://www.wi-fi.net), an industry standard group promoting 
interoperability among 802.11b devices.

The 802.11b standard offers two methods for configuring a wireless network - ad hoc and 
infrastructure.

In an ad hoc network, computers are brought together as needed; thus, there is no structure or fixed 
points to the network - each node can generally communicate with any other node. There is no 
Access Point involved in this configuration. This mode enables you to quickly set up a small 
wireless workgroup and allows workgroup members to exchange data or share printers as 
supported by Microsoft Networking in the various Windows operating systems. Some vendors 
also refer to ad hoc networking as Peer-to-Peer group networking.

In this configuration, network packets are directly sent and received by the intended transmitting 
and receiving stations. As long as the stations are within range of one another, this is the easiest 
and least expensive way to set up a wireless network. 

With a wireless Access Point, you can operate the wireless LAN in the infrastructure mode. This 
mode provides wireless connectivity to multiple wireless network devices within a fixed range or 
area of coverage, interacting with wireless nodes via an antenna.