CCNA Notes (cont) :
26. WAN (Wide Area Network) devices extend the reach of
LAN (Local Area Network) devices. WANs typically span over a wide
area, such over multiple cities / countries. WANs are connected over
serial lines that operate at lower speeds than LANs. Some of the WAN
devices are:
1.
Routers: Routers are responsible for routing the packets in an
internetwork.
2.
Modems: Modems connect to public telephone circuits through dial-up.
3.
CSU/DSU: Stands for Channel Service Unit / Data Service Unit.
CSU/DSUs are used for connecting to Central Office of a Telephone
switching company and provides serial WAN connections.
4.
Communication Servers: These are used for dial in/out to remote
users. Provides RAS Remote Access Server) functionality.
5.
Multiplexers (mux): Multiplexers combine two or more signals before
transmitting on a single channel. Multiplexing can be done by
sharing "time" or "frequency".
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