Wireless Networking Basics

The standards

What is a standard?

Standards are agreed-upon technological "rules" followed by device manufacturers to help ensure compatibility between devices that follow the same standard. Standards provide common ground for manufacturers and their software or devices. As two examples, HTML 4.0 is a standard for Web pages, and TCP/IP is a standard for networking.

Several different standards for wireless communication are in use, including HomeRF, Bluetooth and the IEEE 802.11 specifications. Both HomeRF and Bluetooth are geared toward home networking, while the IEEE 802.11 specifications work well for both business and home networks. IEEE 802.11b is the most commonly used standard for wireless networking today.

802.11b
The first practical consumer wireless protocol widely manufactured was 802.11b. It is limited to 11mbps (much faster than anyone's broadband Internet connection but nothing close to the performance you can get using a wired ethernet connection). The 802.11b standard operates on the 2.4GHz frequency (now a common frequency for cordless phones).

802.11a
802.11a was the next standard operating in the 5.8 GHz band. It provides 54mbps of bandwidth (much faster than 802.11b) but it also has limitations. The 5.8GHz frequency has much less penetration because it is more prone to obstacles (such as trees). But it also has its advantages, there are much fewer devices using the 5.8GHz frequency making it an ideal standard for administrators looking for as little interference (or noise from other wireless networks) as possible.

802.11g
802.11g is the latest wireless networking standard operating on the same frequency as 802.11b but also providing the speed of 802.11a (54mbps). It is also is fully backwards compatible with 802.11b wireless clients. This is the perfect standard to migrate to if you are considering a faster wireless network.

Bluetooth
Bluetooth can be described as a wireless version for USB or infrared devices. It is not intended to provide high quality networking and it only works over short distances. Common uses for bluetooth include sending contact data from your computer to your cellphone, printing to a local printer, or synchronizing your PDA. Unfortunately bluetooth also operates on the 2.4GHz frequency potentially causing interference with your 802.11b/g network... Not to mention beware of using 2.4 GHz cordless phones, they cause all sort of problems on 2.4 GHz networks.

HomeRF
HomeRF, another wireless home networking technology, offers voice, data, and streaming media communications. HomeRF is a wireless specification that defines how devices share and communicate in and around the home (e.g., computers, TV set-top boxes, stereo accessories, and cordless phones). It connects devices 150 feet apart or closer. Like Bluetooth devices, HomeRF-compliant products operate in the license-free 2.4-GHz frequency band and utilize frequency hopping spread spectrum (FHSS) technology.


The Components

Routers

Routers act as the gateway between your broadband connection and your home network. Wireless routers come in various configurations, but most are amalgamations of a four-port wired Ethernet switch and a wireless access point. As the name implies, these devices route traffic between your network and the Internet. Most include built-in DHCP servers that automatically assign the right IP address information to each computer on your local-area network, or LAN. A separate WAN, or wide-area network, interface on the router connects your entire home or office network to your broadband modem, allowing you to share your Internet connection through the router. Most routers also have firewall capabilities, and some include more advanced security features. Some routers even have an integrated cable or DSL modem, eliminating your need for two separate devices.

Access Points

The access point is the hub of a wireless network and the central transit point for all of the data flowing between your wireless network and your wired network. There are as many types of access points as there are networking standards: 802.11b, 802.11a, 802.11g, and Bluetooth. Wireless access points do not offer the rich feature set and the high configurability of most routers because they are designed to add a wireless extension to your network and not to play the role of a central gateway. Nevertheless, access points do typically include some security features, such as encryption.

Adapters

An adapter connects your computer or your PDA to a network. If your computer doesn't already have the adapter that you need built in, you can add one. As with access points, there are as many types of adapters as there are networking standards--802.11b, 802.11a, 802.11g, dual band, and Bluetooth--and each type comes in a variety of shapes and sizes, including PC Cards, PCI and mini-PCI, USB, CompactFlash, and SD. Some wireless adapters are decked out with special features, such as retractable or removable antennae, encryption support, or connection-monitoring software. Before making your purchase, always confirm that the adapter is compatible with your operating system. If you plan to use an adapter at work, you should also check to ensure that it is compatible with any encryption schemes in use, such as LEAP or WPA.

Switches and Hubs

Ethernet is the glue that holds together most networks. It's fast and cheap, and it is integrated into just about everything. If you need to expand your network, an Ethernet hub or switch can come in very handy since most desktops and notebooks include a built-in Ethernet adapter. Accordingly, most wireless broadband routers come with a three- or four-port Ethernet switch built in, allowing you to connect to the router via a fast, wired Ethernet connection. Switches and hubs perform similar functions, but switches can handle multiple simultaneous users without any significant decrease in network throughput.

Bridges

A bridge connects two or more wireless networks in a large home, across the street, or across campus. Bridges attach networks together either through point-to-point or point-to-multipoint connections. Not long ago, bridges were expensive high-end products, but now you can find consumer bridges at very reasonable prices. Unfortunately, this technology varies based on the chipset and the firmware, so bridges tend to work only with other bridges of the same type and model. Before you lay down your cash, make sure that the bridges you're considering will work together.