Wide area network (WAN) technologies are used when communication needs to travel over a larger geographical area.
Telecommunications Evolution
The following is a quick snapshot of telecommunications history:
- Copper lines carry purely analog signals.
- T1 lines carry up to 24 conversations.
- T3 lines carry up to 28 T1 lines.
- Fiber optics and the SONET network.
- ATM over SONET
SONET was developed in the United States to achieve a data rate around 50 Mbps to support the data flow from T1 lines (1.544 Mbps) and T3 lines (44.736 Mbps).
Europe has a different infrastructure and chose to use Synchronous Digital Hierarchy (SDH), which supports E1 lines (2.048 Mbps) and E3 lines (34.368 Mbps). SONET is the standard for North America, while SDH is the standard for the rest of the world.
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