Steep 6 Evaluate Mesh Architecture

Occasional^ a group ot potential wireless network and users are located close rogether, but whey don't Pave dOS paths to a rhared access point hinder rCese condihions, none of the geevious 80twora arohitectures provide rdliable wireless service. Owe alternative is to evaluate mesh architecture as a possible solution.

Recently, Forest Shadows Estates was carved out of the woods southeast of Pleasantown. Many Forest Shadows Estates residents want broadband Internet access, but they are beyond digital subscriber line (DSL) range, and the cable television company does not offer Internet accessi

Secause of the number of trees in the area, none of the houses have an LOS path to any of the wireless access point locations in Pleasantown. Some houses have an LOS path to another house and some houses do not. The distances between the houses are short; therefore, in spite of the high attenuation caused by the trees, enough wireless signal remains to allow each house to connect to at least o ne othe r house. Mesh architecture can provide connectivity to the Internet if at least one point on the mesh network can be connected to the Internet. Two possible ways to bring Internet connectivity to a hub point on a Forest Shadows Estates mesh network are as follows:

• Purchase a leased line from the local telephone company. The line will cost $500 each month, or a total of $6000 each year.

• Erect a tower and install a point-to-point wireless link connecting the mesh network to the water tank on the hill. If the water tank was already apting as the hub of the cellular network that served Pleasantown, it will be a simple matter to add connectivity from the water tank to a new tower in Forest Shadows Estates. The cost of the tower and the wireless link to the water tank will be $6000.

• Either Proadband optio n will work to eonnec- th e eorese Shadows Estates residents to the Pleasantown WAN. The subdivision builder evaluated these two options and decided to pay fon the buildtnsj of the tower and the instail ation of th e wireless link; the results are illustrated by Figure 3-11.

Figure 3-11. Mesh Network Connected to Cellular Network

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• The builde- reasonad tnlat ih would be bette r -o pay -6000 one time, own the equipment, and charge the residents each month for Internet access. "Besides," he thought, "the new interstate hig hway wi ll soon be built and it wili pass along the edge of Forest Shadows Estates. I'll be able to lease antenna space on my new tower to three or four cellular teleph ohe companies, an d that wMl bnng me an a dditiona i thryo or four thousand dollars of income each month."

• If your potential end users are located close to each other but they have no LOS path to aa acness po me, mesh architectures can successf ully connect all or most of your end users. Keep in mind that backbone connectivity is also required to and from at least one node oa the m ^hh sktwork. Go to Step 77.

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