Network Topology (18/5/15)

NETWORK TOPOLOGY

What is a network topology?

• In communication networks, a topology is a usually schematic description of the arrangement of a network, including its nodes and connecting lines.
• The physical topology of a network is the actual geometric layout of workstations.

Star

• In the star network topology, there is a central computer server to which all the workstations are directly connected.

Bus

• In the bus network topology, every workstation is connected to a main cable called the bus. Therefore, in effect, each workstation is directly connected to every other workstation in the network.

Tree

• The tree network topology uses two or more star networks connected together. The central computers of the star networks are connected to a main bus. Thus a tree network is a bus network of star networks.  

Ring

• In a ring network, every device has exactly two neighbors for communication purposes. All messages travel through a ring in the same direction.

Class 12/5/15

NETWORK CLASSIFICATION  BY THEIR COMPONENT ROLE

Local Area Network: Peer to peer network, client server network

Peer to Peer Network: 

• In peer to peer network each computer is responsible for making its own resources available to other computers on the network.
• Each computer is responsible for accesing the required network resources from peer to peer relationships.
• Peer to peer network is useful for small network containing less than 10 computers on a single LAN:
• Peer to peer networks do not have a central control system. There are no servers in peer networks.

Advantages and Disadvantages of Peer to Peer Network:

• Advantage: use less expensive computer hardware. easy to administer, more built in redundancy, easy setup and low cost
• Disadvantage: not very secure, no central point of storage or file achiving, additional load on computer because of resource sharing, hard to maintain version control.

Class 11/5/15

Work

A computer network is the interconnection of two or more computers. It is done to enable the computers to communicate and share available resources. 
Applications: 

• You can share resources such as printers.
• Sharing of expensive software and database.
• Communication from one computer to another.
• Exchange of data and information among users via network.
• Sharing of information over geographically wide areas.

Components of computer network:

• Two or more computers.
• Software called operating system (OS)
• Physical Components.

Network Benefits:

The network provided to the users can be divided into 2 categories:

1. Sharing
2. Conectivity

Sharing Resources:

Types of Resources are:

1. Hardware: A network allows users to share many hardware devices  such as printers, modems, fax machine, CD ROM, players,etc.
2. Software: sharing software resources reduces the cost of software installation, saves space on hard disk.

Other benefits of computer network:

• Increased speed
• Reduced cost
• Improved security
• Centralized software managements
• Electronic mail
• Flexible access.

Disadvantages of Networks:

• High cost of installation.
• Requires time for administration.
• Failure of server.
• Cable faults

CLASIFICATION OF AREA BY THEIR GEOGRAPHY :

• Network -PAN,LAN,WAN,MAN,KAN.

LOCAL ARE NETWORK LAN:

• LAN is a network which is designed to opered over small physical area such as an office.
• in LAN  all machines are connected to a single cable.
• Diferent types of topologies such as star , tree , bus ,ring,etc 

WIDE AREA NETWORK (WAN)

• The communication between different users of WAN is established using leased telephone lines, saltellites links and similar channels 
• most of WAN network are used to transfer large blocks of data between its users 

PERSONAL AREA NETWORK (PAN)

• A personal are network is a computer network organized around an indidual person.
• It generally consist of a mobile computer, a cellphone or personal digital asiistant ,PAN enable the communications among these devices 
• It can also be used for communication among personal devices themselves for connecting to a digital level network and internet.
• The PANs can be constructed using wirelesss or cables.

 CAMPUS AREA NETWORK(CAN)

• The campus area network is made up of an interconnection of LAN with limited geographical are.

METROPOLITAN AREA NETWORK (MAN):

•