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Lesson 2 Networking
Objective Describe the overall importance of networking to eBusiness.

What is networking?

You can think of networking as the set of baseline technologies that enable computers to communicate and share information. Together, these technologies create and connect the different and disparate networks that may be part of your solution. Networking is like a set of pipes. As pipes convey water from home to home, so networking conveys information from computer to computer.

Computer networking involves connecting computers in the same building or office so users can readily communicate with other computers or devices. Switches connect multiple devices in one building on the same network. Computers, for instance, can connect to printers, fax machines, scanners and servers through a switch. Routers tie multiple networks together, such as when a computer connects to an internet router to access the web. Routers control the information going to and from computer networks through security software and programs.
A network is a set of devices (often referred to as nodes) connected by communication links that are built using different physical media. A node can be a computer, telephone, or any other device capable of sending and receiving messages. The communication medium is the physical path by which message travels from sender to receiver. Example media include fiber-optic cable, copper wire, or air carrying radio waves.

Networking is about transmitting messages from senders to receivers over a communication channel. Key issues we encounter include:
  1. Noise corrupts the messages; we would like to be able to communicate reliably in the presence of noise
  2. Establishing and maintaining physical communication lines is costly; we would like to be able to connect arbitrary senders and receivers while keeping the economic cost of network resources to a minimum
  3. Time is always an issue in information systems as is generally in life; we would like to be able to provide expedited delivery particularly for messages that have short deadlines

The above diagram gives a high level overview of a how a network can be configured.

Figure 3-2: The customer cares about the visible network properties that can be controlled by adjusting the network parameters.

Figure 3-2 illustrates what the customer usually cares about and what the network engineer can do about it. The visible network variables, easily understood by a non-technical person include:
  1. Delivery: The network must deliver data to the correct destination(s). Data must be received only by the intended recipients and not by others.
  2. Correctness: Data must be delivered accurately, because distorted data is generally unusable.
  3. Timeliness: Data must be delivered before they need to be put to use; else, they would be useless. Fault tolerance and cost effectiveness are important characteristics of networks. For some of these parameters, the acceptable value is a matter of degree, judged subjectively. Our focus will be on network performance (objectively measurable characteristics) and quality of service (psychological determinants).
  4. Limited resources can become overbooked, resulting in message loss. A network should be able to deliver messages even if some links experience outages.
  5. The tunable parameters for a network include: network topology, communication protocols, architecture, components, and the physical medium (connection lines) over which the signal is transmitted.

Networking and Internet protocol

The eBusiness solutions being built today are Web-based, which itself is Internet-based. Therefore, the most important networking elements for eBusiness involve the hardware, protocols, and software that go into Internet protocol (IP) based networks.
What are protocols and why are they important? A protocol is a set of rules and conventions that determines how computers exchange information over a network. Protocols are important within the context of eBusiness because most solutions are delivered through networks using Internet protocols.
Other networks (usually from pre-Web-era solutions) may well be involved in your eBusiness solution. They can be made to work with other IP-based networks through gateways and other networking interfaces. The next lesson is about one technology used for connecting computers, LANs and WANs.