Networks 1 Flashcards
What is a
network?
an arrangement of two or more computers that are connected for the purpose of sharing resources and data
What do networks allow multiple users to do?
- share data files with each other
- share hardware devices
- share an internat connection and internet services, such as the world wide web and email
- comunicate with each other, using services such as email and messaging
- work together using web-based software, virtual meetings, shared calendars, etc
What are the key characteristics of
LANs?
- small geographical area
- owned by private individuals
- more secure
- slower cables but few users
- less expensive as less hardware is required
What are the key characteristics of
WANs?
- large geographical area
- owned by businesses and organisations
- less secure
- faster cables but shared amongst millions of connections
- more expensive
- mesh network
Describe a
bus topology.
All the nodes on the network are connected to a single cable, known as the backbone. Messages are sent along the cable in the form of electronic signals. A terminator at each end absorbs signals that have reached the end of the cable, preventing them from bouncing back.
What are the advantages of a
bus topology?
- relatively cheap to install since very little cabling is needed
- if one node fails, the rest can still communicate with eachother
- very easy to add extra devices to the network
What are the disadvantages of a
bus topology?
- if the cable is cut or damaged, the whole network stops functioning
- more collisions will occur with more devices and the network will run slower
- all nodes on the network ‘see’ all data traffic, this may be a security risk
Describe a
star topology.
Every node is directly connected to a central node. All data traffic passes through the central node, which is responsible for routing it to its destination.
What are the advantages of a
star topology?
- if one node goes down, the rest of the network will continue functioning
- a damaged cable doesn’t stop the network from working, just the device connected to it
- data traffic is only sent to the intended recipient, this makes it secure
- it is easy to locate faults because they normally only involve one node
- nodes can be added and removed without having to take the entire network offline
What are the disadvantages of a
star topology?
- if the central node fails, then the rest of the network stops functioning
- network performance depends on the capacity of the central node
- a lot of cabling is required, making it difficult and expensive to set up
Describe a
mesh network.
each node is connected to multiple other nodes
in a fully connected mesh network, every node is connected to every othe node
in a partially connected mesh network, some nodes are connected to all nodes while other nodes may only be connected to one or two others
What are the advantages of a
mesh network?
- very fault tolerant, if one node fails, messages are rerouted
- nodes can be added and removed without having to take the entire network offline
- very scalable, any number of additional nodes can be added
- very high performance because each network node is connected to multiple other nodes
What are the disadvantages of a
mesh network?
a fully connected wired mesh network is difficult and expensive to install
What is the
internet?
A shortening of the words ‘inter’ and ‘network’ which together mean interconnected network. It is a network of networks that is not owned by any single organisation or government.
Describe the
structure of the internet.
- Every device connected to the internet is part of a network.
- Local networks connect to the internet via a point of presence (POP) provided by an internet service provider (ISP).
- The ISP’s network is connected to a high-level network owned by a major telecommunication company, such as BT. Each of these companies has its own dedicated internet backbone.
- Network access points (NAPs) interconnect the internet backbones to form a worldwide (partially connected) network.
Routers forward data from one network to another across the internet from source to destination.
