3. Computer networks, connections and protocols Flashcards
What is a network?
A network is a system that allows computer systems to communicate and share resources with each other
What are the advantages of using networks
- Data and files can be exchanged and shared between computers on a network
- Resources & Hardware can be shared (such as printers, scanners and internet connections)
- Communication
- Roaming Profile
Disadvantages of Networking
- Hacking
- Expensive Hardware
- Need specialised staff
What are the advantages of big organisations using large networks?
- Centralised maintenance & updates
- Centralised security
- User monitoring
- Levels of Access
What are the characteristics of a LAN
- A local area network has computers that are connected together over a small geographical area such as a single building or site
- LAN usually has its own dedicated infrastructure and hardware that is owned and maintained by the individual
Where are LAN networks typically found?
LAN networks are typically found in homes, schools, universities
What are the characteristics of a WAN
- A Wide Area Network is where the computers are connected over a large geographical area, over a mile apart
- The owners of the WAN do not own the infranstructure as it is a 3rd party infranstructure
What is the largest WAN?
The Internet
Factors that affect the performance of networks
- Number of devices or users
- Bandwith
- Signal Strength
There are other factors that require you to use your common sense
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What are the two types of network models
- Client-Server model
- Peer-to-Peer model
Describe what the client server network is?
- A client is a computer that sends requests to the server for services and resources
- A server is a computer which manages access to a resource or service and provides the services and resources required by the client
In a client server network:
- The network relies on a central server
- All clients (devices) request services from the server (e.g. print services/file services or web hosting).
Give 5 examples of the services that servers may provide in a client server model
- File servers - hold and maintain user files
- Web servers - hold and share web pages
- Print servers - manage printing across a network
- Mail servers - handle emails between users
What are the advantages of a client server network?
- Central File Storage - users can access them from any computer
- Centralised security - Security can be managed centrally using antivirus software on the server
- Software can be installed or upgraded centrally without having to manually update each client machine
- Backups can be done centrally on the file server
What are the disadantages of a client-server network?
- High initial cost for server as they are expensive
- Specialist required to setup client-serve
- If the server goes down, then the whole service goes down for the network and it becomes inaccessible for all devices and users
- Too many client requests to the server can degrade server performance, bottleneck and overload it
What is the peer-to-peer network?
A peer-to-peer network is a network with no central server, where each computer is directly connected together and they can act as both a client and a server.
Furthermore, each peer has equal responsibility in the functioning of the network.
What are the advantages of a peer-to-peer network?
- Less initial cost / maintenance as no server or dedicated hardware is required
- No specialist required
- Easier to setup and add new devices
- If any device fails/is removed the remainder of devices can continue to function as normal
What are the pieces of hardware required to connect to a Local Area Network?
- Wireless access points
- Routers
- Switches
- NIC (Network Interface Controller/Card)
- Transmission media
What does a Wireless Access Point (WAP) do?
- Creates a wireless network using radio waves to allow network access and connectivity for wireless Wi-Fi devices
- They can also be used to extend the range of a wireless network
- Allows connections through wifi and bluetooth
What are the functions of a router?
- Routers work by inspecting the destination IP address of a data packet and determining if it is on the network or not. It then directs the packets/data to another network or to the destination
- They sit between LANs and WANs to connect the two different networks together - for example, joining a home network to Internet
- Has (public) IP address for LAN
- Designates (private) IP addresses to network nodes
When do data collisions occur?
Data collisions occur when two or more packets send data at the same time