Wide Area Network (WAN) Infrastructure

Wide Area Network (WAN) Infrastructure

As with LANs, there are numerous devices associated with data information flow across a WAN. Together, these devices create the infrastructure of a functional WAN. These devices include:
•Router
•ATM Switch
•Modem and CSU/DSU
•Communication Server
•Multiplexer
•X.25/Frame Relay Switches

ATM Switches

ATM Switches provide high-speed transfer between both LANs and WANs.

Modem (modulator / demodulator)
Modems convert digital and analog signals. At the source, modems convert digital signals to a form suitable for transmission over analog communication facilities (public telephone lines). At the destination, modems convert the signal back to a digital format.

CSU/DSU (Channel Service Unit / Data Service Unit)
CSUs/DSUs are similar to modems, however they send data in digital format across digital telephone loops. They are usually in a physical box, but they may come in two separate units: CSUs or DSUs.


Multiplexers

A Multiplexer combines multiple signals for transmission over a single circuit. This allows for the transfer of various data simultaneously, such as video, sound, text, etc.

Communication Servers

Communication Servers are typically dial in/out servers that allow users to dial in from remote locations and attach to the LAN.

X.25 / Frame Relay Switches
X.25 and Frame Relay Switches connect private data over public data circuits using digital signal. These units are very similar to ATM switches, but the transfer rate of data is not comparable.