Networks

=__ BY THE PORTZ :) 2 main types of network__=  The two main types of network are: 1) Peer- to - Peer Networks 2) Client Server

A **Peer to Peer Network** is where a small number of computers are linked together and can communicate but there is no central file server. It is easy and straight-forward to set up and the software to do so if often contained in the operating system.

A **Client Server** is where there is a main server that contorls the network. The computers linked to it are called clients (hence client server). It required specialiased software running on the server and is used when there is a reasonably large number of users.

=__Network Topologies__= There are three main types of network topologies. These are: 1) Bus 2) Star 3) Ring

Have **one long cable** (backbone), with the file server and workstations attached along it. Each connection is called a **node**. Every computer along the line recievers each signal sent which means if there is a lot of **traffic**, the communication will be **slow**.
 * __Bus Networks__**

**__Star Networks__** Each computer has its own **seperate connection** to the file server. It is more **fault tolerant** since a failing cable does not affect the other computers. Easy to **add individual computers.** More **expensive** as more **cabling** required.
 * Faster** than a bus network, as if there is a lot of work on one computer, this doesn't affect the performance of the others.

__**Ring Networks**__ Computers are linked together by cables in a circle, and data flows **one way.** Suitable for a **small number of computers**, as there is no file server as data is stored individually rather than centrally. Difficult to **add** more computers. If **one computer stops working**, the whole **network will stop.**
 * Cheap** and **Fast** although it can become slow if there is a lot of traffic.

=__Wireless Networking__= This is very useful for connecting portable laptops to a network, or connecting computers in buildings where cabling is difficult. Wireless networking **requires** a **transmitter**, which transmits via an antenna to a wireless network carson the computers. There are usually **not as fast** as a normal computer network as the **antenna has a limited range**.

=__Networking Hardware/Software__=

==In order to run an efficient and effective network, the computers will require certain software and hardware in order to work. __Hardware__ Network interface card and a connection to the network A main central computer to share programs and files A modem of gateway will be needed. User Accounts & Logs==

Disaster Planning

 * Exam Questions **

A network topology is the different types of networks and the different ways networks are set up, for example a ring, bus and star networks are all topoligies (Nic) You are nearly there, but there is a danger this would only get 1 mark. Can anyone add to this?
 * Explain what is meant by the term topology (2 marks)**

Topology is the term used to describe the set-up of a network, in terms of the arrangement of the elements such as links and nodes. Different topologies work in different ways, as data flow is different throughout them. For this reason, certain topologies are most appropriate for certain organizations, and some are more expensive to set up and maintain than others. There are three main types of topology, bus, star and ring. [Mikeyy :o)] A very thorough answer, Mike. Was this another internet search? (the 'z' in organisation gave you away!)

A star network can be set up using different communication links depending on how fast you want each part of the database to be for example you could use fibre optic cabling on one section if you want that section to run fast. Good example However they can be expensive/ costly to set up because the central server can be very expensive, so a small business for example may be unable to afford one. A ring network is good because it is cheap to set up and can be quite fast because all the data flows in one direction around the network, however if one computer fails then the whole network will fail can anyone insert another disadvantage, or more detail here for full marks? (Nic) A further disadvantage to a ring network is that it can be very diffficult to expand. Due to the fact that there must be no breaks in the network, it is extremely difficult to add a new workstation when the network is in operation, and the network usually has to be closed down while this work is carried out, which can cause many problems for an organization. [Mikeyy :o)] Good addition, Mike. This would take the answer up to full marks 6/6
 * Explain the advantages and disadvantages of a star and a ring network (6 marks)**

A company will have to consider what other networks there are to intergrate with the new one, for example they may be required to link an existing network with the new one, and therefore certain networks may allow this better than others. Also they may be able to use some aspects of the existing database to help create the new network, which will help save money and time. They will also have to consider what speeds and performance they require the network to have, for example if they require some parts of the network to be very quick but others not so quick then a star network would be perfect as it allows the user to create different links between the different parts of the network dependant on the required speeds (Nic). Good detail here, but only 6 marks as there are only 3 factors explained. Can you add another one for full marks? The future of the organization may also be a consideration due to the fact that if they may wish to add to the network in future then perhaps a topology such as star would lend itself more easily than a ring, due to the diffiulties of expanding a continuous ring network????? [Mikeyy :o)] Good - I think you mean the configuration of the network - it needs to be in line with their future plans & the example you give is excellent. 8 marks.
 * Other than the cost of the network and the size of the organisation, explain four factors which influence the choice of a network for a company (8 marks)**

A peer to peer network is where a small group of computers are connected together without a central server and the computers communicate directly with each other. they are very simple and cheap to set up. Ho wever they are limited with the number of computers which can be connected and will not be as efficient as other network types. This is very good for the 2 marks allocated to the peer-to-peer section of the answer. Compared to a client server, in which computers are joined together using a server which can be expensive and difficult to set up but will be much more efficient and faster to use. (Nic) You need the same level of detail that you gave in the peer-to-peer section for the client-server section for the 2 marks - can you add more detail here for 1 further mark (currently 3/4)
 * Compare and contrast a peer-to-peer and client-server network (4 marks)**