Wireless Everywhere! (Part 1)

Wireless is fast becoming the standard for computer network connection. Wireless network technology is everywhere you look—from Wi-Fi, to Bluetooth, to wireless (cellular) broadband. In the office, home, car, airports, coffee shops, and hotels—wireless is everywhere!

There are many types of wireless communications used in computer networks today. In the first part of this series, I'll focus on the one of the most popular types of wireless, Wi-Fi.

What's In a Name?
Wi-Fi is the well-known name for the technology used in a wireless local area network or WLAN. Wi-Fi is also known by the IEEE 802.11 standard it supports such as 802.11a, 802.11b, 802.11g, and the new 802.11n. For the purpose of this article, I'll use the generic term "wireless" to reference all the above terms.

Initially, wireless performance just didn't compete with wired connections. The maximum throughput of the initial 802.11b standard was just 11 Mbps (megabits per second) compared to most wired networks that provide a consistent 100 Mbps connection to workstations.

Even the more prevalent next-generation standards (802.11g and 802.11a) only support 54 Mbps at best. Although some manufacturers provide proprietary "turbo" modes to double throughput, they rarely sustain maximum levels.

New 802.11n Standard
The emerging 802.11n standard finally allows wireless performance to effectively compete with wired networks. 802.11n provides throughput from 100 to 300 Mbps (with a theoretical maximum of 600 Mbps) and improves both range and reliability.

To get a better idea of the speed improvement, a file that takes 10 minutes to transfer using 802.11g can be transferred in less than 1 minute using 802.11n. The performance improvements along with the convenience of mobility and ease of connectivity make wireless an attractive and viable alternative to wired networks.

Currently, 802.11n is in it's final draft stage (draft 4.0 was approved May 2008). Although many manufacturers have released "n-draft" products, the final version of 802.11n is not expected to be ratified until early 2009. However, most manufacturers claim their products' firmware will be easily upgradeable to the final standard.

For more information on 802.11n and wireless networks, see the references listed below.

The Benefits
Wireless networks afford many benefits. The most obvious advantage is mobility. Wi-Fi enabled notebooks and smart phones can connect to the network from anywhere within range of a wireless access point (AP). You can put an AP in common areas such as conference rooms, lunch rooms, lobbies and even offer guest Internet access for visitors.

A big benefit of wireless networks is the ease and flexibility of deploying both mobile (notebook) and fixed (desktop) workstations. With wireless, a workstation just needs to be in range of an existing AP to connect to the network. This means you don't need to install a new Ethernet jack or place the workstation near an existing one.

Another benefit is a simplified network topology. Wireless network topology eliminates the need for Ethernet cables that connect each workstation to the network. Instead, you connect a fewer number of access points that each support multiple (10-20) workstations. This greatly reduces the number of Ethernet cables and jacks that need to be installed.

The Costs
But all these advantages come at a price. The most obvious is the new equipment needed, plus new security and network management considerations.

First, you'll need to purchase the 802.11n access points needed for your environment. Each AP must have at least one 1 Gbps wired network connection to support multiple wireless workstations.

If you use power over Ethernet (PoE), 802.11n APs will needs more power than the current PoE standard provides. Some AP manufacturers allow you to use 2 PoE connections for each AP to power the unit. Otherwise, you'll need a nearby power outlet. Eventually, the emerging PoE Plus (802.3at) standard, which is still under development, will provide adequate power for 802.11 APs with a single Ethernet connection.

Next, each workstation will need a wireless adapter (network interface card) that supports the 802.11n standard. Newer notebooks offer integrated adapters that support 802.11n, and there are adapters available for desktops and printers.

Finally, you will need to address security concerns to ensure only authorized users access the wireless network. You should use 802.11i and 802.1X in conjunction with a RADIUS server to authenticate wireless users. Your wireless intrusion detection system (IDS) must recognize the 802.11n technology, and you should continue to monitor for unauthorized (rogue) APs on your network.

WLAN (wireless LAN) switches greatly simplify WLAN management and allow you to centrally manage your WLAN. These specialized appliances incorporate the AP intelligence in the switch and relegate the APs function to a virtual radio transceiver. WLAN switches and can do things that standard LAN switches and APs don't do such as a wireless client location discovery and preemptive roaming.

Wrapping It Up
Wi-Fi offers many advantages and the 802.11n standard makes it a viable solution. But don't go out and get a bunch of APs and replace your wired connections just yet. WLAN design and deployment is a complex undertaking that must be carefully planned. But don't wait for 802.11n to be ratified, the current n-draft equipment is excellent and a great solution for your WLAN needs.

Next time, I'll discuss the other half of the wireless solution — wireless broadband. Please post your questions and comments regarding this article. Also check out the references below for more information on Wi-Fi, 802.11n and related technologies.

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References:
IEEE
Wi-Fi Alliance
Intel and 802.11 (Intel)
FAQ: 802.11n wireless networking (Computerworld)
802.11n (Wikipedia)
802.11i (Wikipedia)
802.1X (Wikipedia)
PoE Plus (Gartner)

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By Harry Hiles, HBH Technology LLC — 27 May 2008