The Physical Connection Posted by Onlinepublications , Monday, March 29, 2010 at 10:26 PM, in Labels: The Physical Connection

The actual connections between the various networks take a variety of forms. The most prevalent for Internet links are 56k leased lines (dedicated telephone lines carrying 56kilobit-per-second connections) and T1 links (special phone lines with 1Mbps connections). Also installed are T3 links, acting as backbones between major locations to carry a massive 45Mbps load of traffic.

These links are paid for by each institution to a local carrier (for example, Bell Atlantic owns PrepNet, the main provider in Pennsylvania). Also available are SLIP connections, which carry Internet traffic (packets) over high-speed modems.

UUCP links are made with modems (for the most part), that run from 1200 baud all the way up to as high as 38.4Kbps. As was mentioned in Section 1.4 [The Networks], page 8, the connections are of the store-and- forward variety. Also in use are Internet-based UUCP links (as if things weren't already confusing enough!). The systems do their UUCP traffic over TCP/IP connections, which give the UUCP-based network some blindingly fast "hops," resulting in better connectivity for the network as a whole. UUCP connections first became popular in the 1970's, and have remained in wide-spread use ever since. Only with UUCP can Joe Smith correspond with someone across the country or around the world, for the price of a local telephone call.

BITNET links mostly take the form of 14.4Kbps modems connected from site to site. Often places have three or more links going; the majority, however, look to "upstream" sites for their sole link to the network.

"The Glory and the Nothing of a Name"
Byron, Churchill's Grave
Zen and the Art of the Internet

2 Electronic Mail

The desire to communicate is the essence of networking. People have always wanted to correspond with each other in the fastest way possible, short of normal conversation. Electronic mail (or email) is the most prevalent application of this in computer networking. It allows people to write back and forth without having to spend much time worrying about how the message actually gets delivered. As technology grows closer and closer to being a common part of daily life, the need to understand the many ways it can be utilized and how it works, at least to some level, is vital.