Physical Connections

There are many ways to connect to a remote network. Some, such as the Plain Old Telephone Service (POTS), offer a direct connection between you and the remote host. Others, such as cable and Digital Subscriber Lines (DSL), allow you to connect, but the connection occurs over a public network (the Internet), which can bring additional considerations such as authentication and security problems. A summary is provided here:

  • Public switched telephone network (PSTN) The PSTN offers by far the most popular method of remote connectivity. A modem and a POTS line allow for inexpensive and somewhat reliable, if not fast, remote access.

  • Integrated Services Digital Network (ISDN) ISDN is a dial-up technology that works much like the PSTN, but instead of using analog signals to carry the data, ISDN uses digital signals. This makes it faster than the PSTN.

  • Cable In an effort to take advantage of the increasing demand for high-speed Internet access, cable TV providers now offer broadband Internet access over the same connection that is used to carry cable TV signals.

  • DSL DSL services are the telecom companies' broadband offering. xDSL (that is, the family of DSL services) comes in many varieties, and as with cable, you need a special modem in order to use it.

  • Satellite Perhaps the least popular of the connection methods discussed here, satellite provides wireless Internet access; although in some scenarios, a PSTN connection is also required for upstream access. Of the technologies discussed in this section, satellite is the least suitable for remote access.

  • Wireless Internet Wireless Internet access is provided by a Wireless Internet Service Provider (WISP). The WISP provides public wireless Internet access known as hotspots. Hotspots provide Internet access for mobile network devices such as laptops, handheld computers, and cell phones in airports, coffee shops, conference rooms, and so on. A hotspot is created using one or many wireless access points near the hotspot location. A hotspot typically requires a WAP at each location connected to a high speed broadband connection such as DSL, cable Internet, or even T1 connections. The technology is based on the 802.11 standards; typically, 802.11b/g and client systems require only an internal or external wireless adapter.