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Wireless Networking
Basics of Wireless Networking
Currently, there are four wireless networking standards competing for your airtime. 802.11b is the corporate darling and has a suitably wide range for use in big office spaces. 802.11a offers bigger bandwidth and fewer interference problems but a shorter range. The most recent addition to the wireless throng is 802.11g, which became an official standard in June 2003. 802.11g combines the long range of 802.11b and the high throughput of 802.11a. It is also fully compatible with older 802.11b equipment.
802.11
802.11 refers to a family of specifications developed by the IEEE for wireless LAN technology. 802.11 specifies an over the air interface between a wireless client and a base station or between two wireless clients. The IEE accepted the specification in 1997.
There are several specifications in the 802.11 family:
- 802.11 - Applies to wireless LANs and provides 1 or 2 Mbps transmission in the 2.4 GHz band using either frequency hopping spread spectrum (FHSS) or direct sequence spread spectrum (DSSS).
- 802.11a - An extension to 802.11 that applies to wireless LANs and provides up to 54 Mbps in the 5GHz band. 802.11a uses an orthogonal frequency division multiplexing encoding scheme rather than FHSS or DSSS.
- 802.11b (also referred to as 802.11 High Rate or Wi-Fi) - An extension to 802.11 that applies to wireless LANs and provides 11 Mbps transmission (with a fallback to 5.5, 2 and 1 Mbps) in the 2.4 GHz band. 802.11b uses on DSSS. 802.11b was a 1999 ratification to the original 802.11 standard, allowing wireless functionality comparable to Ethernet.
- 802.11g - Applies to wireless LANs and provides 20+ Mbps in the 2.4 GHz band.
802.11b
802.11b is currently the most popular and least expensive wireless LAN specification. It operates in the 2.4 GHz radio spectrum and can transmit data at speeds up to 11 Mbps within a 100-foot range. The 802.11b balance of economy, bandwidth, and particularly range, have made it the dominant standard for business, and many employees have taken the technology home with them for work and family computing. The Wireless Ethernet Compatibility Alliance (WECA) has done its part by verifying hundreds of products to make sure they work together. But Wi-Fi has a couple of drawbacks. It shares airspace with cell phones, security radios and other devices so it's vulnerable to interference. And because of data transfer overhead and the inevitable wall or other transmission obstacle, its real throughput is closer to 5Mbps, or about half of its spec.
802.11a
A recent arrival, 802.11a has a couple of advantages over 802.11b. It runs at a less populated frequency (5.15GHz to 5.35GHz) and, thus, is less prone to interference. The 802.11a bandwidth is much higher, at a theoretical peak of 54Mbps. Even though actual throughput is closer to 22Mbps, it still offers a lot more elbowroom than 802.11b does for transferring high quality digital audio and video or other large files across the network, as well as for sharing a broadband connection. And some manufacturers offer proprietary modes that can push throughput a little higher. The main problem with 802.11a is its shorter range: 75 feet compared to 802.11b's 100, forcing you to buy more access points to ensure full coverage. 802.11a equipment is also currently more expensive than its 802.11b counterparts, although the price gap is narrowing steadily. WECA has just begun certifying 802.11a products, which will carry the organization's new Wi-Fi Certified capabilities label.
Because 802.11b and 802.11a use different bands within the radio spectrum, they are incompatible with one another. However, dual band equipment is currently available, which makes it possible to connect at both 2.4GHz and 5Ghz, but prepare to pay twice the price for this gear. If you want to make a choice between the two bands and stick to it, consider these factors: if you already use one or the other standard at your business, you should probably use the same at home to make telecommuting easier; If compatibility and price are not issues, 802.11a's better performance and lower susceptibility to interference could be worth the extra expense. But if you need to cover a lot of group cheaply, 802.11b's the more efficient choice.
Move over Wi-Fi, 802.11g is here!
802.11g, long touted as the high performance successor of 802.11b, was ratified in June 2003, but networking manufacturers flooded the market with 802.11g gear months before it was approved as a standard. Most of the gear that was sold prior to ratification will need a firmware upgrade to bring it up to the final spec. 802.11g has two features that many believe will make it the new dominant Wi-Fi standard: great throughput at around 22Mbps and backward compatibility with 802.11b. That's right: 802.11G operates at the same frequency as 802.11b (2.4GHz) and is backward compatible with the granddaddy of Wi-Fi specs. This makes 802.11g the obvious choice, not only for anyone building a new network, but also for those interested in adding onto or gradually upgrading a preexisting 802.11b network. The only downside to 802.11g is the fact that it uses a more crowded slice of spectrum with only three non-overlapping channels. This will make 802.11a a better choice for some environments, especially those populated with devices that share the 2.4GHz spectrum, such as cordless phones, baby monitors, and microwave ovens.
EarthCam offers our clients Wireless Network Planning, Design and Specification services and can help you implement a reliable Wireless Data Service for your camera network.
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