Determining Network Connectivity Strategies
Determining Network Connectivity Strategies |
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Many large corporations have offices that are spread out in various geographical locations. These offices need a way to connect and remain connected to the main or central site. Different wide-area connection media are used in different parts of the world. Table 7.1 describes the various wide-area technologies and their uses.
Table 7.1 Wide-Area Technologies
| Wide-Area Technology | Definition |
|---|---|
| T1 | Transmits at a speed of 1.544 Mbps, and consists of 23 B channels, which are used for data, and a 1 D channel which is used for clocking. T1 can also be fractionalized into separate 64 kilobytes per second (Kbps) segments. |
| E1 | Used primarily in Europe. Transmits at a speed of 2.048 Mbps. |
| T3 | Transmits DS3 data at 44.736 Mbps. |
| Frame Relay | Packet-switched technology that is considered the replacement for X.25. Commonly runs at speeds up to T1. |
| Digital Subscriber Line (DSL) | DSL consists of an asymmetric digital subscriber line (ADSL), a high-data-rate digital subscriber line (HDSL), a single-line digital subscriber line (SDSL), and a very-high-data-rate digital subscriber line (VDSL). |
Site connectivity can also rely on the use of dial-up mediums such as Integrated Services Digital Network (ISDN), or analog phone lines (POTS) for low traffic links or backup purposes. For instance, an organization might have a small site to which they normally connect by using a fractional T1 line, but in the event that their wide-area provider fails, they can use the POTS line as a backup.
Multiple sites within an organization are normally connected through routers. Windows 2000 Routing and Remote Access offers routing services that enable an organization to cost-effectively connect remote sites to the central corporate site. Sites can be connected through the Internet using VPNs, saving money for your organization. If you have a site that does not require a full-time connection to the central site, then you can implement a demand-dial router-to-router connection, saving wide-area connection costs.