Thomas G. Robinson
, Executive Vice President, CBG Communications Inc.
Considering wireless WANs, individual PANs and offsite SANs, how does your network grow? Whether you are a network planner, a provider of IT services or just a frustrated network user, it's like some sort of high-tech nursery rhyme, trying to determine which technically feasible, efficient and cost-effective direction your network should move in next. Especially if you're the caretaker of a highly distributed network, at some point you may run out of wireline options and will need to focus on potential use of wireless WAN/LAN technology.

Having worked with a lot of wireline (fiber optic, HFC, etc.) institutional networks (I-Nets) for cities, counties, school districts, colleges and universities, I've observed that many have moved or are moving toward wireless technology as a solution to reach especially outlying locations and city center locations where the cost to access or construct high-capacity wireline infrastructure is prohibitive. At this point, many institutions are primarily focused on WiFi and meshed network technology.

WiFi, the market name for products compliant with IEEE 802.11x standards, provides wireless connections for ethernet transport at speeds up to 4 megabits per second (Mbps). 802.11b-based WiFi products operate in the 2.4 gigahertz (GHz) band and have until recently been thought of mainly to create relatively short radius wireless LANs.

Essentially, the wireless network broadcasts through access points to devices with WiFi-enabled network interface cards (NICs) that might be located throughout a corporate facility, campus or office park.

Schools and governments can certainly use the technology effectively in a campus environment. For example, 802.11-based WiFi can be used to link administrative centers that are in close proximity to each other such as a downtown city hall, police command center, fire headquarters, transportation authority, etc. Many school districts have campus environments where an elementary, middle and high school will be co-located, and WiFi links can be very beneficial.

What about linking these WiFi pockets together into a true wireless WAN, or what about connecting remote facilities to the WAN that may be miles from the closest other facility, such as wastewater treatment plants, public works garages or remote fire stations? Where wireline infrastructure development is too costly, WiFi holds some promise here as well, with advances in 802.11b transmission technology centered on directional antennas. Further, where higher transport rates are needed, advances in 802.11a technology now provide transport rates of greater than T-3 (45 Mbps) connectivity.

Institutional users, especially public safety organizations, have expressed concern about the security of WiFi transmissions. There is a wireless encryption protocol known as WEP (Wired Equivalent Privacy) that is built into the 802.11b standard. It is useful for communications that require a low level of security, but can be successfully compromised by knowledgeable hackers. Consequently, transmissions that require a high level of security should employ additional encryption enabled on the sender and receiver customer premise equipment.

The City of Orlando, Fla., and other jurisdictions are looking at the applicability of meshed networks to meet a number of their communications needs. Essentially, a meshed network is, at its heart, a fixed wireless network, but has so many "hopping" points that devices enabled for remote access can literally be deployed anywhere in the service area and maintain a point-to-point connection. In other words, rather than trying to establish a base station that has line-of-sight to all necessary points, many repeater locations are established instead that each have a line-of-sight to the next one down the line, or using point-to-multipoint technology, to any receiver within its line-of-sight radius.

In a downtown area, for example, such technology would be extremely useful by enabling WAN connections to "hop" from building to building, while at the same time enabling many points of remote access for otherwise hard-to-connect personnel, such as policemen walking a beat (with their PDA).

Even inside a facility, network architects are looking at wireless technology, especially if it may be used cost-effectively, instead of retrofitting older facilities with fiber optics or other high capacity cabling. One of my dearest and oldest colleagues in this business used to say that the network world had moved from being defined by POTS (Plain Old Telephone Service) to the new realm of PANS, which he characterized as "Pretty Amazing New Stuff." Well, one area of new stuff really is called PANs–Personal Area Networks. PANs, originally targeted at the home market but very adaptable to the small business, institutional facility and office complex market, enables wireless connections at speeds up to 1 Mbps to occur as access devices are moved from room to room. Essentially, low-power microcells can be established in any room to connect PDAs, laptops, data communications-enabled phones, etc., back to a central server or out to the Internet. Bluetooth is one of the PAN technologies that has gained a significant foothold in the marketplace.

The great thing about PANs is that they can be deployed in a very cost-effective and unobtrusive manner. For residential applications, for instance, the microcells have even been disguised as nightlights, so that they can be powered up and function well, even as they blend into a room aesthetically.

For the network planner, the phrase "what a tangled web we weave" has an altogether different meaning and a special significance. Untangling the web is a constant challenge; while at the same time, making the web stronger through the use of new wireless and wireline technologies is the reward.

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