An Overview of the Information Highway
Based on the presentation given in Mildred Shaw's CPSC 547 class.
Presentation given by:
Quick Links To Presentation Topics:
Note: What follws below is a portion of the presentation. Links to other pages containing additional presentation material can be found at the bottom of this page.
"The InterNet is a worldwide decentralized distributive cooperative interconnection of numerous underlying technologies and organizations with no overall goals, management, or pricing structure."
TCP/IP - Transmission Control Protocol / InterNet Protocol
Designed to be used on reliable and non-reliable networks
This design was a built in feature of TCP/IP because each packet does not follow the same path, therefore re-routing can occour. If one path is down or slow, the packet may be sent elsewhere, still arriving at the same destination.
Delivery time not guaranteed
Since each packet can travel a different route (not pre-defined), TCP/IP is not useful for applications whose information delivery is time-dependant.
ATM - Delivery time is guaranteed
One solution to this time delivery problem is ATM (discussed below).
ATM - Asynchronous Transfer Mode
Full duplex, end-to-end transfer
ATM offers transmissions that are end-to-end, meaning each cell travels the same path. Since the route is pre-defined, cells can be fired off as they are prepared without waiting for acknowledgemens or routing information to be determined.
Cell construction vs. TCP/IP packets.
Cells are 53 bytes long. 5 bytes are used for the header (includes virtual path and channel information) and 48 bytes for the actual information.
Continuous bit stream
Since cells follow a pre-defined route, the information can be sent in one continuous stream of cells.
Ideal for Video On Demand, voice phones, and other time-dependant applications
Video On Demand needs a continuous stream of information to render clear video and sound. ATM facilitates this very nicely and will surely be a factor in the emergence of Video On Demand.
Virtual channels and paths
As seen in the figure below, ATM relies on a network of virtual channels and paths. These channels and paths need not be physical wires in themselves, rather dedicated bandwidth within a given wire. Information flows down a virtual channel.
FIBRE OPTICS
Future infrastructure of the highway
With optical fibre's extremely high bandwith (2 GHz) and data rate (2 Gbps) it is sure to make up the entire infrastructure of the future.
Works on internal reflection
Works on internal reflection. Light enters the fibre at one end, then reflects back and forth inside the fibre (due to the index of refraction of the walls of the fibre - the light becomes trapped) until it reaches the receiver.
Enough bandwidth for high quality video and sound
Video and sound require a large amount of bandwidth to transmit. Optical fibre provides that bandwidth with room to spare.
Less attenuation
The noise distortion in 10km of fibre is equal to the distortion of light passing through 1 pane of window glass. Because of this, signal repeaters can be between 10km and 100km to keep the signal strong. Compared to twisted pair's repeater spacing (2-
1
0km) and Coaxial (1-10km), optical fibre seems to be the intelligent solution to our transmission needs of the future.
THE ROLE OF ENTERTAINMENT
Always preceeds technology
If there's one lesson that we've learned from history, its that entertainment preceeds and drives innovation in technology.
Acrades of the early 1980's vs. present
When we look back at games like Pong and Pac Man, then look at today's video games, we can see the dramatic and speedy evolution of technology driven by creativity.
User interfaces and harware
So far, PC's have focused on speed and reliability, whereas the arcade machines have focused on creativity. When we play a car-racing video game, we sit in a virtual carseat equipped with steering wheel, gas pedal, brake, clutch, and gear shift. When w
e
sit infront of a PC, we use a keyboard and a mouse. We can use this to observe the lack of creative development of the PC.
VIDEO ON DEMAND
Today's cable system is strictly broadcast
Information travels from the cable provider to the recipient only. There is no information returned.
V.O.D. will be full-duplex (interactive)
When V.O.D. arrives, we will be sending information to the cable provider as they are sending information to us (at the same time). We are incapable of doing this with today's cable system.
Possible services
We will be able to watch sports, news, movies, sit-coms, weather reports, and many other services with Video On Demand. We can rewind, pause, stop and fast-forward (provided we are not watching a live broadcast) to exactly where we want to begin viewing
.
Hardware needed
T.V.'s of the future may come equipped with necessary hardware to facilitate such a system, but if it were to be implemented today, we'd need some sort of remote receiver to decipher our selections. Fibre optic connections will also be necessary to allo
w
a full-duplex mode and carry high band-width information.
REFERENCES
Stallings, William. Data and Computer Communications. Macmillan Pub, New York, 1991.
Gates, William. The Road Ahead. Viking Pub, New York, 1995.
http://www.magic.ca/infohighway/atm.html
LINKS TO OTHER PRESENTATION TOPICS
Nora Lee discussed such topics as Gopher, Kermit, FTP, Justice, Job-Hunting and the Wallet PC.
Kevin Ondic gives a detailed analysis of X.500 and ethics on the InterNet.
Tina Petersen explains ISOC, ARPANet, BBS's, MUD's, IRC's, Censorship and the Future of the Information Highway.
Jonathan Cooke
cookej@cpsc.ucalgary.ca
Last Modified February 06, 1996