A Network Wireless Access Point Is A Simple Way Of Extending The Network Wirelessly
A network access point (AP) is a piece of network device that connects the wireless clients to a wired network (and usually on to the Internet from there). As with any piece of bridging hardware, it has at least two network connections and shuffles traffic between them. The wireless interface is typically an on-board radio or an embedded wireless card. The second network interface can be Ethernet, a dialup modem, or even another wireless adapter. Many access points now even include multiple Ethernet ports, which simplifies the creation of a trusted network segment.
The access point hardware controls access to and from both networks. On the wireless side, most vendors have implemented 802.11b/g access control methods (such as WEP encryption keys, “closed” networks, and MAC address filtering), and some newer technology implemented 802.11n standards (WPA / WPA2). Some have added proprietary extensions to provide additional security, such as more sophisticated encryption. Many access points also allow control over what the wired network can send to the wireless clients, through simple firewall rules. Much of this functionality is accessible through either a Java-based tool or a simple web page interface.
DWL-7100AP Wireless Access Point Configuration in AP mode
Unfortunately, as is usually the case with proprietary extensions, these services can be used only if all of your network clients are using hardware from the same vendor.
In addition to providing access control, the access point also maintains its own network connections. This includes functions such as dialing the phone and connecting to an ISP on demand, or using DHCP on the Ethernet interface to get a network lease. Most access points can provide NAT and DHCP service to the wireless clients, thereby supporting multiple wireless users while requiring only a single IP address from the wire. Some support direct bridging, allowing the wired and wireless networks to exchange data as if they were physically connected together. If the access point has multiple radios, it can bridge them together with the wire, allowing for a very flexible, extendable network. Some recent network access point products implemented dual-band radio frequency both at 2,4 GHz and 5 GHz, such as DAP-2590 AirPremier Dual-Band Wireless-N Access Point, DWL-7100 D-Link Access point.
Another important service provided by APs is the ability to “hand off” clients as they wander between access points. This lets users seamlessly walk around a college campus, for example, without ever dropping their network connection. Current AP technology allows roaming only between access points on the same physical subnet (that is, APs that aren’t separated by a router). Unfortunately, the roaming protocol was left unimplemented in the 802.11 spec, so each manufacturer has implemented its own method. This means that hand-offs between access points of different manufacturers aren’t currently possible.
Low-cost models (intended for home or small office use) such as the Linksys WAP11 and D-Link DWL-1000AP currently retail for under $100. Higher-end APs like the Proxim AP-2000 and Cisco Aironet 1200 cost about $600. Typically, higher-priced equipment includes more features, greater range, and generally more stable operations. While some APs will claim 802.11b/g/n (or Wi-Fi) compliance, they are not all alike. Features that set different models apart include:
- Direct bridging to the wired network
- Support NAT and DHCP service feature
- Dual-band radio frequency both 2,4 GHz and 5 GHz
- External antenna connectors
- Greater radio output power (most operate at 30mW, while some operate at 100mW or more)
- Security enhancements such as WPA / WPA2 and tagged VLANs
- Upgrade paths to 802.11g and 802.11a
In general, look for an AP in your price range that will work for your intended application, with the greatest possible range. Single radio APs can support several users simultaneously; adding APs to your network is probably preferable to simply adding higher-gain antennas or amps to your existing AP.
See also:
- How to troubleshoot home wireless network
- How to select the best wireless network
- Wireless network antenna – need to know
- DAP-1360 D-Link wireless range extender
- HOWABN1 Wireless access point, bridge, and repeater
- ASUS RT-N13U Wireless access point and router
