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Anywhere, anytime connectivity-that's the new business rule. Organizations are conducting business on the go. Companies need fast responses and want immediate results. Business environment is fast transforming with instant messaging, text paging, voice services, network access while traveling, and real-time network access in the office.

WLANs are now business-critical. This year the wireless networks, both WLANs and cellular data networks, are poised to get a lot more effective. Draft 2 of the IEEE 802.11n WLAN standard is expected to become final this year. Products based on the draft standard are expected to start appearing by mid 2007 and could have a major impact on enterprise backbone networks. These products, with throughput of 100 to 300Mbps, will be aimed first at the residential, home office and small-business markets, which already have been snapping up so-called pre-11n gear that began shipping in 2006.

At the enterprise level, however, the installation and management of WLAN services has proven to be very time consuming and expensive. As a result, engineers have been developing more efficient 'managed access' mobile solutions that are making WLAN more practical for use in enterprise applications. In addition, many of these technology advances are also in the process of migrating back into improvements for new-generation 'public access' hot spots and evolving unified SMB switching platforms.

Identifying the Challenges
Wireless LAN deployment is inherently somewhat complicated though easier to deploy compared to wired network deployment because of RF nature of the links involved. Each building has different characteristics, and unexpected radio interferences need to be overcome. However, WLAN deployment is not a major challenge once the placements of the Access Points (APs) are freezed on.

CIOs or IT managers often find price points of access points and WLAN controllers on the high side. Vendors have been trying to impress upon them the fact that there is much more to determine actual costs than these initial capital expenses.

Before deploying WLAN, enterprise should consider the variable costs that go beyond simple equipment list prices to ensure that the technology they are investing in maximizes productivity while minimizing cost.

Following are six key issues faced during a typical enterprise-wide wireless LAN deployment:

Technology Selection: Currently, 802.11 a, b, and g are widely used by enterprises. Different technologies can support different data rates. 802.11b can only support a maximum link layer data rate of 11Mbps. On the other hand, 802.11a and 802.11g can go up to a theoretical maximum of 54Mbps. These high rates do not come free, as the range at which 802.11a/g support higher rates is much lower, therefore requiring a larger number of access points to provide similar coverage.

802.11n, which has yet to be fully ratified, is designed to deliver a five-fold increase in data transfer rates compared to current 802.11g equipment and to double the range.

AP Placement and Cell Sizing: The two key objectives of WLAN is to provide connectivity (or coverage) at all desired locations and to provide reasonable capacity to cater to the bandwidth needs of client applications. Depending on the type of WLAN equipment deployed and the intended applications, companies may be forced to overlay two sets of access points-upgrade client devices, add extra access points because of weak technology that limits capacity-and to spend additional money on pre-deployment studies as well as ongoing configuration.

Locations with high user density, or with users running communication-intensive or interactive applications require better capacity than other locations. Bandwidth aggregation through multiple overlapping cells, or use of densely packed small-sized cells are two ways to provide higher capacity at desired locations.

Accounting the Cost: To determine the cost of the deployment and how technology can help, it's important to understand the elements that comprise the total cost of deployment. Every access point (AP) requires an associated Power over Ethernet (PoE) port, a cable run to the place where the AP will reside, and the time associated with deploying all of these. An access point, for instance, that costs $150 can climb up in the $400-550 range when the planning, labor, and PoE are taken into account.

Knowing the limitations of 802.11 and how advanced systems are designed to help can save on equipment as well as labor costs. Costs can be lowered by implementing thin wireless access points (APs), particularly in larger networks. Traditional wireless deployments utilise thick APs, each configured individually.

Limited Channels: Because of limited number of available channels in 802.11 wireless LAN technologies, channels need to be re-used beyond certain re-use distance. Without proper assignment of channels and power calibration of access points, co-channel interference can degrade the performance of wireless LAN. The 802.11b and 802.11g wireless LAN standards operate in the 2.4 GHz band. This band only offers three non-overlapping channels. Each channel is a separate 'pipe' of bandwidth. All clients attached to the access point share that same bandwidth.

The task of the channel assignment process is two-fold-reduce the interference among neighboring cells, and provision enough capacity.