Unit 1: Factors Affecting Networks
Size of the organisation
- Needs to range from small LAN to global WAN
- Some communications are limited by distance they have to travel
How will the system be used?
- What applications does the user require?
- Do they do large amounts of processing?
- Will they need large data storage?
Intergrate Existing Systems?
- Most of time systems are not developed from scratch they need to fit with exisiting systems
- Does it fit with exisiting operating systems and does it support current peripherals?
Unit 1: Factors Affecting Networks (2)
Performance/ Speed of Processing:
- Different parts of the organisation have different requirements?
- Real time e-commerce systems require higher performance
- Some organisatons must perform batch processing over night. e.g. banks.
- A large global WAN needs more devices than a local LAN would need.
- A bank would need higher security as it handles people's personal data whereas a school doesn't need as high security.
Unit 1: Peer to Peer Vs Client Server
Peer to Peer:
- Cost: Cheaper as no server required & low operating costs
- Status: All machines have the same importance
- Network Manager: No manager needed, all users responsible for their own files
- Security: Poor, as all resources are shared
- Back Ups: Cannot be made centrally. Users back up their own data.
- Network Size: Suitable for small networks (15 or less)
- Cost: More expensive because need a server and Mainteneance costs high.
- Status: One machine is more important than others
- Network Manager: Manager needed who allocates access to resouces in the network.
- Security: Better security as it is all centralised and one person is resposible for all.
- Back Ups: Backups done centrally.
- Network Size: More efficient for large networks.
Unit 1: Factors when Designing Security Policies
The Data Protection Act puts an onus on the council to keep the information secure because otherwise it could be misused.
Physical Security - protecting the hardware and software using physical methods to protect the computer equipment and restricting access. E.g. Locks and biometric methods.
Software Security - involves logins and passwordsto restrict access to the computer - using levels of authority to access files and programs.
Investigation of Irregularities: e.g. query any transactions that are made by a customer out of the ordinary.
Firewalls: hardware or software working in the network to prevent communication which is not allowed from one network to another. A firewall controls the data traffic between two networks.
Audit Trails: provide records which can be used to track the transactions being made - they act as a deterrent to staff because they know they're being checked - allows a record to be kept of who edited data or accessed the data.
Unit 1: User Accounts & Logs
Everyone who uses a computer is given a user account.
All users of a network can change their password, desktop settings and manage their files.
It is up to the network manager to decide:
- which files the user can access
- if the user can copy files
- if the user is allowed to install software
When a user logs in they enter their username and password. The system allocates which files and resources to the user.
When a user no longer requires access they can log out.
The log in procedure ensures that only authorised access is made and provides audit trail of what resouces each user has used.
Unit 1: Disaster Recovery
Disaster Planning 1: plan what you'd do if hardware, software or data is lost.
Loss could be caused by:
- Hardware failure
- Bugs/ Viruses
- Natural Disasters
- Deliberate Damage
- Accidental Damage
Disaster Planning 2: is essential to:
- Minimise the damage caused
- Get the systems working again very quickly
- Ensure all the staff know the procedures for recovery data.
Unit 1: Disaster Recovery (2)
- Set up a budget for the recovery plan
- Hardware can be replaced depending on how much they have
- What problems could occur? E.g. data gets lost or hardware gets damaged
- Liklihood of them occuring.
- No organisation can afford to lose their data
- Back ups should be done regularly. This means in worst case scenario the business will have a backup of the data from not too long ago which they can up-date/ carry on from. Backups can be done at night as they take a long time.
Unit 1: Topologies
Advantages of Ring:
- Network not dependant on central computer.
- Each computer has the same access as the others so noone can 'hog' the network.
Disadvantages of Ring:
- A break in connection means the network fails.
- Cannot keep the network running whilst new computers are added.
Advantages of Star:
- Fault tolerant - if one cable breaks others still work as multiple paths are used
- Easy to add computers without affecting the network
Disadvantages of Star:
- Higher cost because more cables needed
- The network is dependant on central hub if it fails then network wont work.
Unit 1: Wireless Networking
Advantages of Wi-Fi:
- Inexpensive LAN's can be set up without cables
- Allows people the freedom of working anywhere signal can be recieved.
- Ideal for networks in old listed buildings where cables cannot be added.
Disadvantages of Wi-FI:
- There may be health problems associated with using Wi-Fi
- There may be security problems even when encryption is used.
- Wi-Fi networks have limited range (150 ft)
- Can get interference when Wi-Fi signals overlap.
Unit 1: Code of Conduct
Code of Conduct - A set of rules and an agreement made by a manager/ employerwhich their employee's must obey regarding use of the internet and ICT.
Code of Conduct contains:
- Respecting the rights of others
- Abiding by current legislation
- Authorisation - what parts of the system they are allowed to use
- Protecting hardware and software from malicious damage
- Data access permissions
- Security policy - defining rules about password disclosure, data transfer, use of email/ internet
Legal Issue -serious & against law - if itis illegal then police can fine you/ lead to imprisonment.
Moral Issue- issue which although most people would consider wrong is not illegal.
Disinformation- false information intended to mislead, this can be a moral or legal issue.
Unit 1: Remote Management
The network manager can perform many tasks:
- Check on emails being sent within the company
- Check on internet sites visited by employers
- Guide users through any problems they're having
- Log users off their computers if they have walked away but left them logged on.
- Shut down any computers that are not functioning correctly.
- Add new software or hardware to the network.