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CHAPTER 7: WIRELESS NETWORK FUNDAMENTALS Wireless Network Configuration
Ad-hoc Mode (Peer-to-Peer Workgroup)
The Institute of Electrical and Electronics Engineers (IEEE) standard f or wireless LANs (WLANs),
802.11, 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 s tructure, nor are
there fixed points to the network — each node can generally communicate with any other node.
There is no access point involved in this configuration. It enab les you to quickly set up a small
wireless workgroup and allows workgroup members to exchange data or share pri nters as
supported by Microsoft Networking in the various Windows operating s ystems. Some vendors also
refer to ad-hoc networking as Peer-to-Peer group networking.
In this configuration, network packets are directly sent and receiv ed by the intended transmitting
and receiving stations. As long as the stations are within range of one a nother, this is the easiest
and least expansive way to set up a wireless network.
To set up an ad-hoc workgroup operating with standard protocols, do the f ollowing:
Set all stations to connect in Ad-hoc mode (or Peer-to-Peer workgroup mode).
Set all stations to use the same network name (or SSID).
Set all stations to either (1) use no WEP encryption key or (2) use an identic al WEP
encryption key.
Set all stations to use the same wireless channel for communication.
Infrastructure Mode
With a wireless access point, you can put the wireless LAN into the Infr astructure mode. It provides
wireless connectivity to multiple wireless network devices within a fixed range or area of coverage,
interacting with a wireless node via an antenna.
In the Infrastructure mode, the wireless access point converts airwave da ta into wired Ethernet
data, acting as a bridge between the wired LAN and wireless clients. Connect ing multiple access
points via a wired Ethernet backbone can further extend the wireless network coverage. As a
mobile computing device moves out of the range of one access poi nt, it moves into the range of
another. As a result, wireless clients can freely roam from one Acces s Point domain to another and
still maintain seamless network connection.
To set up an infrastructure network operating with standard protocols, do t he following:
Set all wireless stations to connect in Infrastructure mode.
Set all stations to use the same network name (or SSID).
Set all wireless access points to use the same network name (or ESSID).
Set all stations to either (1) use no WEP encryption key or (2) an identical W EP encryption
key.
Set up wireless channels used by individual access points. (It is not necessary to s et channels
on the stations as the stations will automatically scan through all cha nnels for the nearest
access point.)