6.2 - Networks Flashcards
What is a LAN?
Local area network
Two or more computers connected together within a small geographical area
What is a network topology?
Arrangement of the various computing devices which make up a computer network
What is a bus topology?
An arrangement where nodes are connected in a daisy chain by a single central, communications channel
What is a star topology?
An arrangement where central node or hub provides a common connection point for all other nodes
How does a bus network work?
- all nodes are connected to a single backbone cable
- each end of the backbone is connected to either a terminator or a computer which stops signals ‘bouncing back’
- each node is passive
- data is sent in one direction at a time only
- only one computer can successfully transmit at a time
Advantages of a bus network?
- inexpensive to setup
- devices can be easily added
- good for small networks
Disadvantages of a bus network?
- main cable is the single point of failure
- limited cable length
- performance degrades with heavy use
- poor security
How does a star network work?
- computers are connected to a central node (switch/hub)
What does a switch do in a star network?
Sends each communication to the specific computer it is intended for
What does a hub do in a star network?
Broadcast the message to every device on the LAN
How does a switch direct the messages to the specific devices?
MAC Addressing:
- every networked device contains a NIC (network interface card)
- each NIC is given a unique MAC (media access control) address which is hardcoded into it when manufactured
- the switch holds all of the MAC addresses for each device connected to it so it can send the correct packets of data to the correct devices
What are the advantages of a star network?
- easy to isolate problems
- good performance
- more secure if a switch is used as data is only sent to the recipient
What are the disadvantages of a star network?
- can be expensive to setup because of the length of cable required
- central device is the single point of failure
What is the physical topology?
How devices are physically connected
What is the logical topology?
How the devices communicated across the physical topology
