Computer networks, connections and protocols Flashcards
avantages netowrking
users can share files
users can share peripherals and connections to other netowrks e.g internet
users can access files from any comp on network
servers can control secuiry software updates and backup of data
communication w/ other ppl
two types of netowrk
LAN -Local area network
WAN - wide area network
LAN
covers small geogrpahic area
all hardware for lan owned by organisation useing it
LANs are wired w/ utp cable, fibre optic or wireless using wifi
WAN
large geographic area connecting lans together
infrastructure between lans leased from telecomunication companoes who own and manage it
wans connected by telephone lines, fire optic cables or satellite links
what are computers in lan connected to
a switch
what are computers in wan connected to
router
job of the router
personal home device for connecting to internet - multi function all in one device:
acts as router, switch and wireless access point
disavantage netowrking
increased secuiy risk to data
malware and viruses spead very easily between comps
if server fials comps connected to it may not work
computer may run more slowly if lots of data travelling over netowrk
how does bandwidth affect performance of netowrk
bandwidth is amount of data that can be sent and received successfuly in given time
not a measure of how fats data travels, but how much data can be sent on transmission media
mesaured in bits per sec (bit rate)
factors affecting erofrmace of netork
bandwidth
num of users
transmission media
latency
error rate
how does num of users affect netork performances
too mnay users slow down netowrk if insuffiencient bandwidth for data
how does transmission media affect performance of netowrk
wired connections have highhr bandwidth that wireless
fibre optic cables have higher bandwidth than copper cables
how does error rate affect netowrk performance
less relible connections increase num of erors occuring when data transfered
means data has to be resent until ariving correctly
signal quality of wirelss connections dpeendant on range of devics from wirelss access point and other envitonmental factors
signal quaity of copper cables determinded by grade of material used which reduces interference
length of cable also a factor
how does latency affect netowrk per4mance
latency is delay from transmitting data to receiving it
caused by bottlenecks in infrastructure of netowrk
eg by not using switches to apporpriately segment traffic on netowkr
hardware such as switches and transmission media may not operate on same spd
whats a server
special comp on netowrk not used as workstation
dedicated to serving files and managaing other services
both LAN and WAN can use servers
what is a netowrk using a server and what is a network not using a server
using server:
client server model
not using server:
peer to peer model
job of server
control access and security to one shared file store
manages access to internet
manages printing jobs
provides email services
runs a backup of data
makes reuqests to server for data and connections
avantages client server model
easier to manage security files
easier to take backups of all share ddata
easier to install software pdates to all computers
disavantages client server model
expensive to setup and maintain
requires it specilaists to maintain
server is single point of failure
users will lose access if server fails
what is a peer
comp on a network, is equal to other peers
how does peer-2-peer model work
peers serve own files to each other
each peer resposnsible for own security and backup
peers have own printers
can send print jobs to another peer to process but other peer must be switched on to communicate ith connected printer
avantge peer2pper model
very easy 2 maintain
specialist staff not reuqired
no dependency on single comp
cheaper to set up
no expensive hardware required
disavantage peer2p model
network less secure
users need to manage own backups
can be difficult to maintain well ordered file store
what does every comp need to connect to network
NIC - Netowrk interface card
every device on a network has a NIC
they are integrated into comp
use a protocol (a set of rules) to determine how connection should work
allw a device to conect to either wired or wireless netowrk
WAP
wireless access point
allowes wireless enabled devies to connect 2 network without cables
more convenient
less bandwidth than wired connection
secuirty more a concern with wirless connections
connection sometimes not as strong or relaiable as wired connections
a switch (hardware to connect to lan, in detail)
sends data between comps on a lan
segment network by forwardibg traffic to correct location
learn which devices are connected and understand how to forward traffic in intelligent way
uses NIC address on device to route traffic
a router (detailed)
sends data between networks
creates a wan from a number of lans
cannot connect to a wan withot router
uses IP address (internet protocol) to route traffic
transmission media - copper cables (utp)
wired connections assure max bandwidth security and reliability
with twisted pair cables wires are twisted around each other to reduce interference
there are normally a set of wires for transmission and 4 receiving
gradeof copper and insulating material aggects quality of overall cable and therefore the bandwidth
transmission media - fibre optic cables
uses light to transmit data
cover much longer distances and greater bandwidth than copper
backbone of internet uses fibre optic cables
def protocl
a set of rules that allow two devices to communicate