The central piece of hardware in your WLAN is the access point (AP). It sends and receives signals between clients on the network. The AP provides a central point of connectivity for all of the wireless clients and can interface with an Ethernet network or broadband Internet connection. In addition to providing connectivity to wireless NICs (Network Interface Controller), the AP can provide other network services, usually supplied by a server or router in a large network. Some of the additional services that an AP may include are:
– Dynamic Host Configuration Protocol (DHCP) services: DHCP automatically assigns Internet Protocol (IP) addresses to client computers as they connect to the WLAN. DHCP eliminates the need for you to manually configure each computer with a permanent IP address.
– Router services: Typically, an Internet Service Provider assigns a customer a single IP address. A router enables several users on the network to share a single broadband Internet connection. If your ISP uses a proprietary modem/router, you do not need this functionality in an AP.
-Print server: Some APs can act as a print server, and have one or more places to connect printers (both serial and USB ports), so that you can share the printers on the network. This is a nice option, but you also can get standalone wireless print servers that may cost less and won’t degrade performance of your AP.
Look for an access point that is Wi-Fi compliant in the standard that you have chosen, and that is compatible with your operating system. Many APs also can operate in one or more modes: normal, client, bridging, and repeater. Look for one that can operate in all of these; it will give you flexibility if you decide to extend or modify your WLAN in the future. The definition of each of these modes follows:
– Normal mode: The access point operates as a normal AP.
– Client mode: The AP operates as a network client (like an NIC) and does not communicate with NICs, just other APs.
– Bridge mode: The AP communicates directly with another AP capable of point-to-point bridging. Usually both APs must be the same model or from the same manufacturer. This is useful for extending a WLAN between buildings.
– Repeater mode: The AP repeats the signal from another access point, extending its range.
Insider insight: It’s possible to create an ad hoc network between two or more wireless clients without using an AP, but the performance will be poor. Ad hoc connections are really only useful for connecting a couple of clients (like PDAs or laptops) for a quick file transfer.
There are dual-mode APs available that support both the 802.11a (5 GHz) and 802.11g (2.4 GHz) standards. These APs cost somewhat more than single mode devices, but give you greater flexibility when upgrading your network in the future.