Determining the Costs

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Before arriving at the cost of your WLAN, you must know the network's specific elements. To know which components will be necessary for a WLAN project, draw up a preliminary sketch of the requirements and design. For example, the cost structure will differ radically between a network that provides Internet access in a small HotSpot, a WLAN that services a small business, and a WLAN that accommodates a large organization with a variety of applications.

The components:

Wireless NICs: Each WLAN computing device will need the ability to connect to the wireless network, this includes devices such as PDAs, laptops, PCs, printers and so forth. Thus these devices will need to be equipped with the correct network interface card, typically a PC card. (Unless you have unique application requirements, the user devices will not require additional components.) However, since more and more computing devices ship with wireless ability embedded, there may be no need to purchase a wireless NIC for each user device. But, for each wireless NIC that must be purchased, plan on paying on the average of $65 for each 802.11b card, and figure an additional 25 percent for 802.11a cards (although 802.11a prices could come down as usage of this technology grows). It's too early to predict the average cost of an 802.11g card.

Access Points: Most WLAN deployments will be some type of infrastructure network, which means you will need at least one access point. (Of course, an access point isn't needed for an ad hoc WLAN.) Access points vary widely in price, ranging from less than $100 (for a home or SOHO WLAN) to $2000 for APs that serve enterprise WLANs. The cost depends on the features the device provides. (The benefits gained from an access point's advanced features will likely make the difference cost-effective.)

Since an access point has limited range and capacity, most corporate WLANs will need more than one AP to provide adequate coverage. The site survey will determine the number of access points needed. However, if you are trying to determine the WLAN's preliminary costs before performing a site survey, plan on approximately one AP per 70,000 square feet (6503 square meters) of coverage area. This assumes a range of about 150 feet (45.7 meters) without any limitations due to attenuation. For the WLAN to provide a consistently high data throughput rate, a single AP's capacity also must be limited, typically to somewhere between 30 to 50 end-users. So even though a single AP might be able to provide adequate geographical coverage, additional APs might be needed to provide adequate data throughput rates.

Also consider the costs for mounting the APs and running the necessary network cabling to each access point from the Ethernet switch or hub. If you use in-house labor, calculate the time and cost of (1) running cable for each AP, (2) installing and mounting the APs, and (3) installing network cards in all user devices, and (4) making applicable configuration settings.

Professional Fees: Besides having a professional to perform the site survey, a large organization may want to consider hiring a company specializing in wireless LAN installations. If so, the contract should cover the costs of the site survey and the equipment installation. Here's an example of what to expect for these types of professional services. Cable runs cost approximately $100 for each AP (depending on the scope of your network), then add another $150 or so per AP for installation and mounting hardware. If you also want the contractor to install the network cards in user devices and make applicable configuration settings, you will need to include some additional costs for those services.

There are firms that will handle the entire WLAN project—feasibility, assessment, site survey, financials, and the business case. The fees for the "project" approach, which can be relatively high, may be well worth the expense, especially if the IT staff is already overburdened with its current workload.

Power. A wireless LAN installation may require the addition of electrical wiring and outlets to power the access points. If you don't have an outlet within a couple yards from an access point, you need to install new outlets. The cost can run upward of $300 per outlet (depending on the facility's geographical locations). Or you can sidestep the "power" issue altogether by using power-over-Ethernet (PoE) technology. (Do not use extension cords.)

Switches and Hubs: If you're designing a WLAN to link to an existing wired network, determine if there are enough ports open on the wired network's switches/hubs to connect the WLAN's APs. If not, be sure to include in the WLAN financials the costs for additional switches/hubs to interconnect the APs. The cost of these hardware devices varies widely—from $50 to several hundred dollars—depending on features.

Redundancy: I bet you didn't plan for redundancy, i.e. having spare hardware on-site to replace components that may be defective. This would apply to only the APs and the antennae since they are the only components that offer a single point of failure. If you have a spare on hand, you can replace an access point within an hour or less, but it could easily take a couple of days if you have to order the AP. Only you can assess how important the availability of wireless networking is to your organization and how long the network can be down. My thoughts are that it is advisable to have, at a minimum, one spare access point.

Servers: In addition to the network hardware components, authentication and encryption are required for securing WLAN communications. These capabilities are embedded in the wireless NIC, the AP, and in a back-end wireless authentication server that uses the same protocol as the other components. The wireless server can be a Remote Authentication Dial-In User Service (RADIUS), Lightweight Directory Access Protocol (LDAP), or other server already in place to enforce user access rights. Or it can be a separate server that connects to these other servers specifically to enforce the access rights of wireless users. The costs vary widely, but plan on spending at least $1000 if an extra server is needed for authentication. (Note that some access point vendors have built access control functions into their access point.)

Internet connection: This cost, ranging from $30 for a DSL connection up to $1000 or more for a T-1 line, pertains almost exclusively to the WISP business models, since most corporations and other organizations will already have Internet access.

Additional security measures: This includes extra firewalls, additional security software, etc. The costs for these extra security measures can run from a few hundred dollars to thousands of dollars.

Network management and maintenance: Operational support such as network monitoring and problem resolution and the tools to aid in these exercises should be included in a WLAN's overall cost figures. Such tools usually cost anywhere from $5000 on up.

Intelligent boxes: Refers to catchall switching in combination with dumb access points. Some enterprise-size WLANs may be built upon a thin AP/intelligent box architecture. The prices vary, but the average combined price of an access point and switch port is just under $900 (a price that is similar to an enterprise-class access point). While this type of solution is expensive, the more APs deployed the less the overall cost.

That pretty much sums up the hardware. Of course, there will be additional costs, e.g. purchase of mobile computing devices, project management (in the enterprise environment), user training and support, and IT staff training.



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Going Wi-Fi. A Practical Guide to Planning and Building an 802.11 Network
Going Wi-Fi: A Practical Guide to Planning and Building an 802.11 Network
ISBN: 1578203015
EAN: 2147483647
Year: 2003
Pages: 273

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