The Future Of Computer Networking
In this unit, we have looked at many aspects of computer networks.
The Internet has been woven through every topic covered, because
in networking terms, the Internet is now the "only game in
town".
In particular, we have not given any particular coverage of the
Open System Interconnection Reference Model (OSI-RM) of
the ISO.
This represents a major change in the unit.
It remains to be seen whether the Internet can maintain its
dominance in years to come. The following are some factors which
will influence this:
- The implementation of IPv6, the "next generation" of the
Internet Protocol, IP.
- Adoption of the Internet protocols (TCP/IP) as the standard
for business applications, instead of proprietory network
systems.
- Continuing commercialisation of the Internet itself - in
particular, can businesses make a profit out of it?
- New developments in the World Wide Web
- Whether the Internet can scale to become the "Information
Superhighway(tm)"...
Developments In The World Wide Web
In the last lecture, it was claimed that the WWW was an excellent
example of client/server computing "done right".
The WWW now generates the major proportion of all Internet
traffic. Its success is, in large part, due to the way in which
makes the use of networks so simple.
The WWW is based on three fundamental concepts:
- The HyperText Markup Language, HTML. This is being continually
extended, with little agreement on desirable standard features. It
is clear that this could lead to big problems in the future as new
browsers define new, incompatible, markups. The latest, and
greatest new innovation is "applets".
- The HyperText Transfer Protocol, HTTP, currently version 1.0,
may soon be upgraded to version 1.1 with some useful new
features.
- The Universal Resource Locator, URL has some limitations, and
the use of URNs has been proposed as a replacement. This will not
happen.
Business And The Internet
Many businesses now have (full) Internet connections. It has
become common to distinguish a business's Intranet from
the outside Internet with one or more firewalls
separating the two as previously discussed.
A significant aspect of this is that businesses can move to using
TCP/IP networking on their internal network. Nevertheless,
proprietory protocols still have the major market share of this
market.
Ways in which businesses can profit from an Internet presence
include:
- Access to basic services, particularly email. This is
still a major business reason for net access.
- Access to valuable information via the Web.
- Internet advertising, both on their own server and at other
sites, see later slide.
- Electronic storefronts and trading using the Web. This is the
cutting edge of "electronic commerce", see later slide.
- Electronic publishing.
WWW Advertising
Popular Web sites now sell advertising space on their pages.
Typically, an "ad" is simply an in-line image configured as a
hyperlink to the advertiser's own "home" page.
Recent (and proposed) developments in HTML appear to have been
designed to facilitate advertising. For example:
- Flashing (blinking) text
- Frames - sections of the page that remain fixed in place even
when the rest of the page is scrolled.
There is a very great amount of debate as to the
effectiveness of Web advertising. Some of the contentious issues
include:
- How to measure the number of potential customers who have seen
the ad - are "hits" to the page a reliable indicator? This is
important, because ads are normally priced according to how many
"eyes" the publisher can promise Ñ the "CPM".
- How can you tell if the person who downloads the page has
actually read it, or the ad it contains - eg, is "time to next
mouseclick" useful? Does anyone read Web ads?
Electronic Storefronts
In this model of Internet commerce, a company's WWW server is set
up to allow "on-line purchasing" of goods or services, in a manner
analogous to using a mail order catalogue. The enabling
technologies for this are:
- Web pages can contain HTML "forms", with fill-in text fields,
"radio buttons" and all of the paraphenalia needed to obtain
information on the product to be supplied.
- The HTML form is transmitted from the client browser to the
server, where the information is acted upon by a "Common
Gateway Interface" (CGI) program. This program can typically
act as a front-end interface to a corporate DBMS. The CGI program
generates, as output, HTML which is returned to the browser.
- Effective and secure payment systems are crucial to the
success of this model. Currently, the majority of transactions do
not use any particularly innovative technology (eg, plain text
credit card numbers are transmitted!). This will change.
WWW Businesses
Many companies and individuals are already making serious money on
the Web. They seem to fall into the following categories.
- Internet spiders (Bots?) trawl the Web for information about
Web sites and build databases of key words and phrases. A company
then makes available a "search engine" page to allow people to
query these databases. Because these pages are very popular,
advertising space on them commands a premium price. Companies such
as Yahoo! and Lycos have made their founders seriously rich by
floating on the stock exchange.
- Browsers. The Netscape corporation has seen a stratospheric
rise in the value of its shares after its IPO. Some might ask
why?
- Internet hardware:
- The telecommunications carriers who supply the raw bit pipes
have done well. Whether they can continue to do so is not clear.
- Router manufacturers such as Cisco, Bay Networks and 3Com.
- Consultants and advisors....
- Micro$oft...
WWW Browsers As Universal Clients
An interesting recent development is the use of the WWW model for
purposes somewhat different to the original.
Modern browsers, particularly when used in conjunction with CGI
programs running on a server can perform a very wide range of
functions. For example, if an organisation wishes to move a
mainframe application to a client/server environment, they can now
realistically consider using HTML/HTTP and a WWW browser to
achieve their goal.
With all new browsers supporting the execution of "applets"
(written in Java), the potential exists for the browser to take
over many jobs previously managed by the operating system (file
management, for example) or by applications software such as
spreadsheets and word processors. A variation on this theme is
seen in the recent emergence of "network computers" from Oracle,
Apple and others.
Further, browsers may start to become useful in entirely new
fields such as management of industrial plants.
It is difficult to predict where this could lead...
Multimedia And The Internet
Some (rather enthusiastic) pundits have suggested that the
Internet and WWW model is sufficiently flexible to become the new
medium for pay TV, Video on Demand, and all the rest.
At present the WWW has limited support for other media - the most
successful forms are first downloaded and then run through a local
player, eg sound files and MPEG movies. Other approaches, such as
"real audio" work less well.
In the future, the WWW will have to include support for the
existing Internet multimedia structure, the Mbone. Mbone is the
"multicast backbone", a virtual network layered on the Internet
and designed for efficient distribution of:
- Audio conferencing and broadcasting using the vat and
rat tools
- Video conferencing and broadcasting using vic and
others
- Shared graphic tools such as "virtual whiteboards"
(wb) in support of the conferencing tools.
This lecture is also available in PostScript format.
The tutorial for this lecture is Tutorial #21.
Phil Scott