Chapter 5: Networking Flashcards
Network
A collection of computers and peripheral devices connected together
What are a few types of networks?
- LANs
- WANs
- MANs
LAN
Local Area Network: a collection of computers and peripherals connected together within a limited area
What kind of areas are LANs used in?
- Residences
- Schools
- Laboratories
- Office buildings
WAN
Wide Area Network: a collection of computers and LANs connected together over a large geographical area, often using leased infrastructure
MAN
Metropolitan Area Network: spans an entire city or campus, formed by connecting together multiple LANs
Order the following network types in ascending order of size:
- MANs
- WANs
- LANs
3 1 2
What three main categories does the use of networks benefit?
- Sharing resources
- Communication
- Centralised management
Advantages of using networks for Sharing Resources (3)
- Shared resources can be accessed anywhere on the network from any computer
- Ability to use shared peripheral devices, e.g. printers and scanners
- Internet connection can be shared
Advantages of using networks for Communication (3)
- Email can be used to communicate with colleagues
- Messaging systems can be used to chat while working
- Files can be transferred between computers easily
Advantages of using networks for Centralised Management (4)
- User profiles and security can all be managed centrally
- Software can be distributed across the network as opposed to individual installation
- Users can use any PC on the network and access their own files
- Data can be backed up centrally
Disadvantages of using networks (5)
- Purchasing network cabling and file servers can be costly
- Managing a large network is complicated and requires training. A network manager usually needs to be employed
- If the file server goes down, files on the server become inaccessible. The computers can still be used, but are isolated
- Viruses can spread to other computers throughout a computer network
- Risk of being hacked, especially with WANs. Security measures, e.g. a firewall, are needed to prevent this
Network topology
A schematic description of the layout of a network
Bus Network
A topology where each device is connected to the main cable, referred to as the bus. Any device can transmit at any time, but only one transmission can occur along the main bus at any one time
Pros and Cons of Bus Networks (3 | 4)
Pros
- Easy and inexpensive to install
- Easy to add new computers to network
- Broadcasting onto a bus is faster than transmitting around a ring network through many devices
Cons
- Main cable failure leads to the whole network going down
- Cable failures hard to isolate: affects all attached computers
- Not secure - all data broadcasted on one cable
- Performance slows down as the amount of traffic increases
Ring Network
A topology where each device is connected to the next in a loop. Uses a token-passing protocol to manage transmission one device at a time
Pros and Cons of Ring Networks (3 | 3)
Pros
- Not dependent on a central computer
- Token passing protocol is simple and reliable
- Consistent performance even when there is a lot of traffic
Cons
- A single node or link failure could potentially disrupt the whole network
- Not secure - all connections shared
- Slow - data goes around the whole network
Star Network
A topology where each device has its own cable connecting it to a central device, which can be a switch or server
Pros and Cons of Star Networks (4 | 2)
Pros
- Failure of a cable only affects one station
- Consistent performance even when the network is heavily used
- Easy to add new computers
- Most secure - messages transmitted down unshared links
Cons
- Can be costly to install - lots of cabling needed
- Dependence on a single switch: if this fails, the whole network goes down
What kind of networks are the following topologies used in:
- Ring?
- Bus?
- Star?
- LANs and MANs
- LANs only
- LANs and WANs
What two ways can the computers in networks be configured to behave in?
- Client-server
2. Peer-to-peer
Peer-to-peer
A method of organising devices in a network where all devices are of equal status instead of being designated specialised roles. Every computer can access resources on another computer, provided access rights have been granted
How are the computers in a peer-to-peer network connected together?
They are cabled together to form a LAN
Why might a small company use a peer-to-peer network?
It is not cost-effective to have a specialised server
Peer-to-peer: 1. Computer status 2(+/-). Setting up and maintenance 3(+/-). Management 4(+/-). Backing up 5(+/-). Dependency 6. Usage 7(+/-). Number of computers
1. All computers have equal status 2+. Easy to set up and maintain 3-. No centralised management - less secure 4-. Each computer backed up separately 5+. No dependency on a server 6. LANs only 7-. Impractical for over 10 computers
Client-server
A method of organising devices in a network where some computers have roles as servers. These provide resources and services to other computers, known as clients. Management of the network and shared resources and files is centralised at the server
What are the two kinds of computers used in a client-server network?
- Servers: holds data and controls access
2. Clients: where the user actually works
What is the job of a server computer? (3)
- To control access to shared resources e.g. files, printers
- Where all the data is stored, making data storage centralised
- May have specialised roles e.g. print servers, dedicated to controlling access to shared printers and queuing print jobs