Course Material –Lecture Notes
Web browser: A web browser enables access to the Internet through a common
interface. The Internet provides a wealth of information and has become vital to the
productivity of both home and business users. Communicating with suppliers and
customers, handling orders and fulfillment, and locating information are now routinely
done electronically over the Internet, which saves time and increases overall productivity.
The most commonly used browsers are Microsoft Internet Explorer, Netscape Navigator,
Mozilla, and Firefox.
Instant messaging: Instant messaging started in the personal user-to-user space;
however, it soon provided considerable benefit in the corporate world. Now many instant
messaging applications, such as those provided by AOL and Yahoo!, provide data
encryption and logging, features essential for corporate use.
Collaboration: Working together as individuals or groups is greatly facilitated when the
collaborators are on a network. Individuals creating separate parts of an annual report or a
business plan, for example, can either transmit their data files to a central resource for
compilation or use a workgroup software application to create and modify the entire
document, without any exchange of paper. One of the best-known traditional
collaboration software programs is Lotus Notes. A more modern web-based collaboration
application is a wiki.
Database: This type of application enables users on a network to store information in
central locations (such as storage devices) so that others on the network can easily
retrieve selected information in the formats that are most useful to them. Some of the
most common databases used in enterprises today are Oracle and Microsoft SQL Server
An application programmer would list the services that his or her application needs—for
example, a guarantee that each message the application sends will be delivered without
error within a certain amount of time or the ability to switch gracefully among different
connections to the network as the user moves around.
A network operator would list the characteristics of a system that is easy to administer
and manage—for example, in which faults can be easily isolated, new devices can be
added to the network and configured correctly, and it is easy to account for usage.
A network designer would list the properties of a cost-effective design—for example,
that network resources are efficiently utilized and fairly allocated to different users.
Issues of performance are also likely to be important. This section attempts to distill these
different perspectives into a high-level.
CS 6551 Computer Networks – Unit-I