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Introduction MOREnet Frame Relay Connections Local Frame Relay WAN Wireless WAN Point-to-Point Dedicated Connection

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Wide Area Networking Options for REAL

Introduction

The goal of this document is to provide Missouri Library systems with some basic options for connecting branch libraries to the Internet and to the main library.

MOREnet Frame Relay Connections

Each Library system in the state of Missouri is eligible for a direct connection to the Internet delivered through a leased network data circuit by the REAL program. Each branch library could have a direct connection as well, depending on the local and REAL budget amounts available. A direct connection requires that the library have a minimum of two networked computers, which essentially forms a Local Area Network (LAN) as shown in Figure 1 below.

MOREnet Frame Relay Connection
Each library has a direct connection to MOREnet with dedicated bandwidth to their site.

Figure 1. Direct Connection to MOREnet

The bandwidth of a leased network data circuit typically ranges from 56 Kilobits per second (Kbps) to 1536 Kbps [T1 or 1.4 Megabits per second (Mbps)]. A leased circuit typically is mapped as a Permanent Virtual Circuit (PVC) from one location to another. Virtual circuits are priced by the distance between two sites — as if they were directly connected (not including the distance to the local phone company switch). For example, in Figure 1 a circuit would be mapped from the library to the next router on the MOREnet backbone. A Committed Information Rate (CIR) of 1.4 Mbps would guarantee that this much bandwidth would always be available to the customer on this line.

Local Frame Relay WAN

With this option branch libraries would connect through a local frame relay service to the MOREnet direct connection at the main library. This option is feasible if there is only one telephone company servicing the area and/or the library system has an E-rate discount greater than MOREnet's (~64 percent).

Customer Campus Network Diagram
(Frame Relay WAN)

Figure 2. Local Frame Relay WAN

There are several disadvantages to this option for library systems. Locally managed systems require more technical support on site and all sites have to actually share the bandwidth of the main router as shown in Figure 2. Additional router and CSU are needed at the local building.

Wireless WAN

This locally managed option can be cost effective and provide greater bandwidth if the area is relatively flat and distances are less than approximately 10 miles between sites. The devices generally used in these situations are wireless bridges or routers that attach to the wired LANs at each site and transmit data to the other site via radio frequency as shown in Figure 3.

Figure 3. Wireless WAN

Radio WANs usually operate in the unlicensed 2.4 gigahertz (GHz) frequency. Using spread spectrum technology, bandwidth of 10 MB and more can be attained for at least 10 miles. The radio transceivers must have line-of-site so topography and tree lines are major concerns. Towers can be built to compensate for differences in topography but these can be costly. Typically a site evaluation is done by the wireless vendor before investigating this option further. Radio WANs are attractive because there are no ongoing costs, but E-rate discounts do not apply.

Point-to-Point Dedicated Connection

A Point-to-Point dedicated connection refers to a dedicated leased line between two sites. This type of connection uses some of the unused copper wire in existing phone lines. It is leased from the telephone company for a monthly charge but the customer is responsible for the devices at each end that allow data to be transmitted across the wire. It is commonly called an "unloaded copper" or "clear channel" connection since it does not go through the frame relay cloud. Consider it as a cable running from site A to the local telephone switching site to site B. The gauge of the wire represents another variable in determining the viability of this technology.

To send data across this wire you must have a device at each site that can send data across this type of connection. This could be a router with a CSU/DSU or there are special types of equipment that bridge data across this type of connection. Figure 5 shows both types of Point-to-Point connections.

Customer Campus Network Diagram
(Point-to-Point WAN)

Figure 4. Point-to-Point WAN

Point-to-Point connections will generally not be a viable option for Library systems because they are distance sensitive and require local technical support and expertise. The bandwidth of a routed connection typically will be 56 Kbps to T1 and is determined by the CSU/DSU on the line. The bandwidth of a bridged connection depends on the specifications of the proprietary equipment, the gauge of the wire and the distance.