NetworksHow to choose a networkFactors when choosing a network Reasonscost of network Includes costs of the server, cabling, software,

and cost of their party communication services. It is a limiting factor for small and big organisations because you may spend too much money.

size of organization The size of an organisation is a big factor because if it is a small network you may only need a LAN but if it is big you need a WAN.

how the system will be used If the system is primarily for storing information then you will need to have a lot of space if you are using it for processing power then you will need to have a good processor in the server and it must be efficient.

existing systems If there are existing systems you need to find a way to hook them up to the network and make sure there are no conflicts.

performance required The performance is very important you need to take into consideration about the topologies, server needed and how the network will support the user.

security issues You will need to determine the budget that is available to implement the network and ensure that it is adequate to cover all of the work that is required.

Type of networks and topologiesClient server networks is where several computers are connected to one or more servers - These are networks that have one main server that other workstations are connected o, they are the best for large networks because the server is normally more powerful than the other workstations and this is where all the programs and files are stored.

Peer to peer networks is when the computers in a network are arranged in a way that all of them have equal status - These are networks that have the same status meaning they can communicate with each other freely without the need of one computer being the central computer. These are good for file sharing over the internet because anyone that is a part of the networks can access each other’s files.

Factor Peer to peer Client serverCost saving No server is needed so

computers can be the sameServers are expensive to buy

Low operational cost Less set up and maintenance cost Cost of setup and maintenance is higher

Computer status All machines have same status The server is more important than the rest of machines

Network manager All users take responsibility for the network so no network manager needed

Network manager is needed due to specialist knowledge to manage the network.

System expertise All users must have IT knowledge Only the network manager needs to know about IT users don’t

Easy to set up They can be set up by anyone who knows little bit about IT

Network operating systems require technical knowledge to set up

Reliance on server There is no server so don’t need to worry about it

If the server fails the network is unusable

Peer reasonability All users can decide on what resources they share with the other user

The user needs little specialist knowledge because this is performed by the admin

Security Poor security because resources shared

Better security due to one person having responsibility

Back up Cannot be made centrally in one place so users have to back up on their own

Centralised so only the admin can install software and make back ups

File storage Hard to find files because they are not centralised

Easier to find files because centralised

Network size Only suitable for small networks of 15 or less devices

Higher load tolerant so suitable for large networks

Topology Description Advantages DisadvantageBus/Ethernet This is when all

devices connected to the network is linked together with a cable called a backbone

Cost effective

East to install because there isn't a lot of cables

Easy to add devices to the network.

Ring A ring network is when the devices are arranged in a circle and data is passed between them until it reaches its destination.

Each computer has the same access as the others so no one computer can hog the network.

Higher transmission speeds / Data flows in one direction only (so large volumes can be transmitted).

No collisions.

Faults are difficult to locate.

It is impossible to keep the network running whilst equipment is added or removed because there is only one path for the data to follow.

Break in cable and network won’t work.

Star Uses a central connection point to connect all the devices on the network together the central point is a hub, switch or router.

Fault tolerant – if one of the cables fails, then the other computers can still be used.

Load tolerant – extra computers can be added without much loss in performance because all computers have their own path to the server

Easy to add extra computers – extra computers can be added without disturbing the network.

Different speeds are possible on different spokes/ arms of the network.

Higher cost – the large amount of cabling needed makes it more expensive.

Dependence on the central server/hub.

Advantages of Wi-Fi:

• allows inexpensive LANs to be set up without cables • allows people the freedom of working anywhere a signal can be received • ideal for networks in old listed buildings where cables would not be allowed to be installed • global set of standards – you can use Wi-Fi all over the world • can use a variety of devices such as tablets, mobile phones • Health and safety – tidier desktop with no trailing cables.

Disadvantages of Wi-Fi:

• power consumption is high – which means laptops soon exhaust their rechargeable batteries • there may be health problems in using Wi-Fi • there may be security problems even when encryption is used • Wi-Fi networks have a very limited range (e.g. 150 ft) • can get interference if wireless network

Software components

User account

User accounts are given to people who use a network, it is normally set by the network administrator or manager, these accounts will have certain rights that they can do for example change desktop settings, password, manage file in storage area. The network manager is incharge of what software users can use, what files is shared with them, if the user can copy the files and also if user can install their own software.

Auditing

This is when you keep a record of who has done what on the network for example it keeps a record of usernames, when and how many times they logged on, programs they used, files accessed and details of the changes they made, it is important to identify abuse of the system.

Security strategies

Used to minimise security threats, you can do this by using passwords and user ID’s to authenticate users of the network, virus checkers for making sure if there are viruses so they can be removed, firewalls to prevent software and hardware and files from hackers, encryption to keep data secret when transferring data over the network.

Configuration management

Process of managing and maintaining the information about the network for example when it needs repair, expansion or upgrading. By doing this it makes it easier to repair expand or upgrade the network, it will be optimised to run faster, less server downtime, security be optimised, possible to roll back to a previous backup and also keep record of all the changes made to the network s you don’t need to write down the settings.

Remote management

Used to see which users are on the network, check emails sent in by company time, internet sites users visited, check the hardware, number of users doesn’t exceed the licenses, guide users if having problems, make sure there is no unauthorised software, log a user off, see if components of the network is failing or not, rebuild stations by adding software.

Disaster planning (backup and restoration);

Disasters could be caused by hardware failures, software bugs, natural disasters, deliberate damage, and accidental damage. Disaster planning is needed to minimise disruption, get the system working again, and ensure staff know what to do to recover data.

Backup should be taken regularly, kept away from the computer in a fireproof safe or offsite, use of RAID systems or use of grandfather father and son principles in batch processing systems.