Page 85 - DCAP104_EXPOSURE_TO_COMPUTER_DISCPLINES

Exposure to Computer Disciplines

Notes Objectives

After studying this unit, you will be able to:

• Understanding network structure.
• Discuss network architecture.
• Explain network topologies.
• Explain network protocols.

• Discuss network media.
• Understand network media.

5.1 Network Structure

Networks are usually classified using three properties: Topology, Protocol, and Architecture.
Topology specifies the geometric arrangement of the network. Common topologies are a bus,
ring, and star. A bus topology means that each computer on the network is attached to a common
central cable, called a bus or backbone. This is a rather simple network to set up. Ethernets use
this topology. A ring topology means that each computer is connected to two others, and they
arranged in a ring shape. These are difficult to set up, but offer high bandwidth. A star topology
means all computers on the network are connected to a central hub. These are easy to set up, but
bottlenecks can occur because all data must pass through the hub. You can consult the diagram
below to see these three topologies:

Figure 5.1: Network Structure

Protocol specifies a common set of rules and signals the computers on the network use to
communicate. There are many protocols, each having advantages over others. Let’s run through
the common ones:
• TCP/IP : Transmission Control Protocol / Internet Protocol. This was originally developed
by the Defense Department of the US to allow dissimilar computers to talk. Today, as many
of us know, this protocol is used as the basis for the internet. Because it must span such large
distances and cross multiple, smaller networks, TCP/IP is a routable protocol, meaning
it can send data through a router on its way to its destination. In the long run, this slows
things down a little, but this ability makes it very flexible for large networks.

78 LOVELY PROFESSIONAL UNIVERSITY