3.1 NETWORK types and PERFORMANCE (lan, wan, topology + more) Flashcards
what is a network?
a network is more than one computer system connected together allowing for communication and sharing of resources
what is a lan
a local area network
features of a lan
- situated geographically close together (same site)
- school / office
- within the same building or small site
what is a wan
wide area network
features of a wan
- geographically distant computer systems
- across a country or the world
- third party communication channels
advantages of client - server network
- controlled centrally and easily backed up
- hardware, software and resources shared easily over the network
disadvantages of client - server network
- large amounts of data traffic congestion slows the network down
- if a fault occurs within the server then the whole network will fail
- IT technicians required to manage and maintain the network
- malware (viruses and worms) can spread quickly across the network
advantages of peer to peer network
- not dependent on a server
- easy to setup
- perfect for quickly sharing files
disadvantages of peer to peer network
- no central device to manage security of backups
- computer performance decreases the more devices connected
what are data packets?
data broken down into smaller parts
what happens when all the packets arrive at the destination?
data is reassembled back into an original file
what is the header of a packet?
source address
destination address
packet number
protocol
what is the payload of a packet?
the data itself
what is the trailer of a packet?
a calculation on the data to see if any errors or corruption have occured during transmission
what is network topology?
the layout of computer systems on a network
what is a name for devices in a network (and topology diagram)?
nodes
what are the two types of topology?
star and mesh
how does star topology work?
each computer system connected to the central hub / switch
the hub / switch looks at the destination address and transfers the packets directly
what are advantages of star topology?
- improved security data packets are not sent directly
- new systems can be attached directly to the central system
- transfer speeds are generally fast
disadvantages of star topology
- extra hardware (hub / switch) required to be purchased
- if central system hub/switch fails the whole network is unusable
what is a mesh topology?
where each computer system is connected to every other computer system
what is a partial mesh?
where some nodes (printer or something) are only connected to every other node
how does mesh topology work?
data packets are transferred to the destination address along the quickest path node, to node
if a pathway is broken it can take an alternative route
advantages of mesh topology
- if one cable / system fails then data packets can take an alternative route
- withstand large amounts of data traffic
- new systems can be added to the network without disrupting the entire topology
disadvantages of mesh topology
- large amount of cables expensive to install and maintain
- redundant cabling should be avoided (connecting systems that wont ever communicate)
name some factors that affect the performance of a network
bandwidth
users at the same time
data collisions
interference (thick walls)
applications used
distance to travel
signal strength
amount of data to transfer
server / cpu performance
