CPSC 689/602--Spring 1997

Computer-Supported Cooperative Work


Paper Report

Title:Networks
Author:Vinton G. Cerf
Citation:Scientific American 265(3), September 1991


Vinton G. Cerf, is the founder father of the Internet. He currently holds the position of senior vice-president at MCI. His talks on topics such as the future of the Internet, expl osion of usage, needs for increasing bandwidth and infrastructure etc., are well received by members of the Internet community.

We now live in a small world. Technology has reduced distances and cut across cultures, making information access faster and easier. Information, residing on a server located in a far -off place, may be only a few milliseconds away. Telephony and data communication have bridged distances to a great extent. Almost the entire world is networked, using fiber topics and other communication media. In this paper Vinton describes briefly, some of the technologies, that existed at the time of his writing.

There are two methods of sending information over communication links. They are circuit switching and packet switching. Circuit switching involves the setting up of a dedicated path for the duration of transmission. In order delivery of data is the rul e, but this method has a large path-setup time. Packet switching allows better utilization of available network bandwidth but does not guarantee in-order delivery of packets.

Ethernet is a commonly used packet switched network, it operates at speeds upto 10 Mbps. It increases channel throughput, by first sensing a channel and transmitting, only if it perceives the channel to be idle.

Token-ring is another technology, which improves on the collision minimization scheme of the ethernet, by issuing tokens. Only computers that have tokens can transmit.

FDDI, is a very recent technology that uses Fiber at the physical layer and achieves high throughput rates. It uses laser or light for transmission. The technology is failure resistant to a certain extent.

Researchers at the University of Western Australia developed the DQDB technology, which is a slight modification of the token ring.

Frame Relay is similar to the virtual-circuit system, that leaves the error checking and re-transmission, to the receiver and sender nodes.

ISDN is a digital technology, that permits very high data rates, suitable for video conferencing. However, it has not been widely accepted by users of networking technologies, despite the promise it holds.

One of the hottest technologies is the Asynchronous Transfer Mode (ATM), which can achieve throughputs upto 622 Mbps.

Though, there are a number of other technologies for data transmission, the key to their adoption, seems to be open architectures.

With the widespread proliferation of networks, some issues that come to the fore are security, authentication, integrity, privacy and cryptography. No amount of research, seems to satisfy users on these sensitive issues.


Report prepared by: Ajay Kumar Gummadi Email: ajay@ee.tamu.edu
Discussion date: February 17, 1997            Report date: February 17, 1997