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WANs       Wide Area Network

Local-area networks accommodate local users - people within a building or on a campus. Wide-area networks (WANs) connect users and LANs spread between various sites, whether in the same city, across the country, or even around the world. "Remote access" refers to a simple connection, usually dialed up over telephone lines as needed, between an individual user or very small branch office and a central network. Your business gains access to the Internet through some type of remote connection. A single user can dial up an ISP via modem. Multiple users within a campus might choose to rely on a router to connect to the ISP, which then connects the campus to the Internet.

In general, LAN speeds are much greater than WAN and remote-access speeds. For example, a single shared Ethernet connection runs at 10 mbps. Today's fastest analog modem runs at 56 kbps - less than 1% of the speed of an Ethernet link. Even the more expensive, dedicated WAN services such as T1 lines don't compare (with bandwidth of 1.5 mbps, a T1 line has only 15% of the capacity of a single Ethernet link), and the faster WAN T2 to T4 lines are too expensive for most companies.  For this reason, proper network design aims to keep most traffic local - that is, contained within one site - rather than allowing that traffic to move across the WAN.