Communication Flashcards
Define network
A collection of computers, servers and other devices (nodes) connected to one another to allow the sharing of resources and data.
Define internet
A global computer network providing information and communication facilities; consisting of many interconnected networks
Define network topology
The arrangement of the nodes (computers, switches, routers etc.) and of the connections between them that make up a network.
Define data packet
A formatted unit of data that is transmitted over a packet-switching network
Define protocol
An agreed format, or set of rules, which allows differing networked devices to communicate.
Define connectivity
Connecting devices to each other in order to transfer data, including cabling and wireless
Advantages of networks (6)
• Share hardware, software, and data/files
• Easier for internal communication/can send email
• Central backup
• Easier to monitor network activity
• Centrally controlled security
• Can access data from any computer
Disadvantages of networks (5)
• A network manager may need to be employed – expensive
• Security problems – files sent between computers could spread a virus
• Hackers can gain access to data more easily
• If the server is down, all workstations on the network are affected
• Initial cost of servers, communication devices, etc. can be expensive
Define LAN and WAN
Local Area Network- computer systems located relatively close e.g. a school
Wide Area Network- computer systems located relatively distant e.g. the internet
Common network topologies (4)
Bus
Ring
Star
Mesh
Layout and process of a bus network
Nodes are connected to a single cable on which data can be sent, called the bus with terminators on each end.
The bus carries packets along the cable and checks the destination address in the packet at each node.
The node either ignores the packet or processes the data.
Advantages of a bus network (3)
• Easy to implement and add more computer systems to the network
• Quick to set up – well suited for temporary networks
• Cost-effective – less cabling
Disadvantages of a bus network (6)
• Difficult to troubleshoot the bus
• Performance degrades as additional computers are added
• If there is a problem with the main cable or
connection, the entire network goes down
• Low security – all computers on the bus can
see all data transmissions
• Proper termination is required
• Data collisions (two computers trying to send a packet at the same time) are more likely, which causes the network to slow down
Layout and function of a ring network
Nodes are connected in a ring or a loop. Packets are sent around the ring, being passed from one node to the next until they arrive at their destination
Advantages of a ring network (4)
• Data is transferred quickly and consistently
• Data transmission is relatively simple as
packets travel in one direction only
• Adding additional nodes has very little impact
on bandwidth
• It prevents network collisions
Disadvantages of a ring network (4)
• If any of the nodes fail, the ring is broken and data can’t be transmitted efficiently
• If there is a problem with the main cable or
connection, the entire network goes down
• It is difficult to troubleshoot the ring
• Because all nodes are wired together, to add a
another you must temporarily shut down the
network
Layout of a star network
Each node is connected to a central node, also known as the hub
Advantages of a star network (6)
• Good performance/fast network speed
• Easy to set up
• Possible to add more nodes without taking the network down
• Any non-centralised failure will have very little
effect on the network
• Minimal network collisions
• Better security
Disadvantages of a star network (2)
• Expensive to install – more cabling required
• Extra hardware required, such as a hub
Define circuit switching
A network technology that provides a temporary dedicated link between two nodes regardless of the number of switching devices through which the data has to travel. During the connection, no other data can be transmitted along the same route.
