Flashcards
networks and protocols
Cards in this deck (30)
- 1what is a network?a network is collection of computing devices connected for the purpose of communication
- 2what are the advantages of a network?- users can share resources
- users can share peripherals and connections to other networks like the internet
- users can access resources from any computer on network
-users can communicate with others on network - 3disadvantages of networks?increased security risks to data, esp on internet. susceptible
risk of spread of malware and viruses between computers
if reliant on server and server fails, it may impact other computers in the network
large volume of data travelling on network could lead to reduced performance - 4what is a wide area network?a wide area network is a network that covers a large geographical area
uses telecommunication lines
Internet
nationwide Bank network - 5what is a local area network?a network that exists within a defined and limited location.
(more secure than WAN as theres no external communication)
-a small home network
-college network - 6devices needed for LANnetwork interface card:
allows all communication to and from the network
switch:
controls flow of data around a network. All machines and devices are connected to the switch.
it decides the packets of data that need to go to whichever part of network
ethernet cable:
type of cable that is used to transmit data physically throughout a network. connects nic to switch - 7devices for wangateway
translates the protocols and settings of one network into the protocols and settings the other network can understand. used when two networks need to be joined
modem:
used when a network needs to access the internet or use telecommunication lines in WAN
it carries out modulation and demodulation where it translates transmitted data between computers (dealing with and telephone lines (dealing with analogue data) - 8what is a client-server network?a client server model is one where one central computer acts as the network controller and controls security and access to network resources
+better security, all files are stored centrally and require access rights
+data and other resources can be shared
-expensive to install and manage
-professional IT staff are needed for maintenance - 9what is a peer to peer network?a peer to peer is where there is no central server and each pc is an equal participant in the network. they are connected to share files
+no reliance on one computer for access to resources
+doesnt require special operating system
+cheap to set up
+easier to maintain
-difficult to secure as each pc is independent
-difficult to back up as data is distributed between different systems - 10what is a topology?Physical configuration of network which shows the layout and how all the devices on a network are connected together.
there is bus ring and star topology - 11what is a star topology ads/disadsA star topology is designed with each node connected directly to a central switch or computer which acts a router to transmit messages. (client/server)
+if one cable fails, only one station fails, none affected
+ better security as direct communication between server and no interception of others
-expensive, length of cable
-dependant on central server and if it fails, whole network is affected. - 12what is a bus topology ads/disadsone where all the nodes are connected to a single cable which is plugged into a terminator at both ends
+inexpensive and as it requires less cable and less additional hardware
+ easy to install
-if main cable fails, whole network is affected and network data cant be transmitted
- heavy traffic of data can reduce performance
-low security- transmitted data exposed to all computers - 13what is a ring topology? ads disadsone where all of the computers are connected to one another in a circle.
data is passed from one computer to the next until it reaches desired computer.
+ Cheap to install – no server, less cable
+ equal accessibility. Each computer has the same access to resources as another
+Fast transmission rates are possibe
- Break causes whole network failure as all on one cable
-Network has to be shut down whilst devices are added or removed as all data travels on the same one path
-security, data exposed - 14what is the purpose of a switchConnects devices to other devices on a network.
Is intelligent and uses packet switching to send data on to specific destinations based on the hardware MAC address. - 15what is a routerReceives packets on a network and forwards them to the correct destination based on the IP address via the fastest, least congested route
- 16what is a WAPAllows devices in a network to connect to the network wirelessly.
- 17what is are physical transmission media?fibre optic cables
copper twisted pair
coaxial copper
Fibre optic cables transmit data through light so no electrical interference. Data can be transmitted over very large distances more expensive but the data capacity is much higher.
coaxial cable:
The coaxial cable/inner core carries the signal and the outer braiding shields the inner core. it protects the signal from electrical interference. issues because there have been poor connection issues
copper twisted pairs. It is made up of twisted pairs of copper wires that carry the electrical signal. The twisting and voltage usage means it cancels out the interference. cheaper - 18what are the different methods of data transmission?serial: DATA TRANSMISSION WHEREBY BITS OF DATA ARE SENT ONE AFTER THE OTHER DOWN THE SAME WIRe
parallel: PARALLEL IS WHEN DATA SIGNALS ARE SENT SIMULTANOUSLY ALONG RIBBON WIRE - 19what are the different modes of transmissionsimplex= when transmission only occurs in one set direction
half duplex: when transmission occurs in both directions but not at the same time
duplex: both directions of transmission at the same time - 20difference between mac and ip address?Mac address is used for routing frames on a LAN. IP address is used for to route packets on a wan
frame is data wrapped by bits used by LAN protocols. A packet wrapped bits used by WAN protocols - 21what is packet switchingPacket switching is a method of communicating data across a network by breaking them down into packets.
the packets have all the destination address info and info on how to reassemble.
no Physical connection
-susceptible to error
+uses any available routes
+ makes it a lot more efficient
+good for large volume of data - 22what is circuit switching?circuit switching involves a physical link between two devices for the duration of the communication, until transfer is terminated:
+no need to split up data as there is an exclusive connection path. data arrives in order
+less susceptible to error
- involves cables and resources, expensive
-wires are unavailable - 23what are methods of error checking?parity check
checksum
echoing back - 24what is parity checking?parity check works by adding an extra bit bit at the start of the data as a significant bit.
this most sig bit is added to create an odd parity or even parity of the group of bytes, by making the total number of 1s even or odd
the type and position of parity are specified in the protocol
the receiving computer sees this and will detect and error if calculation of 1s doesnt add up with parity
it will send back - 25what is checksumWHERE GROUP OF BYTES ARE ADDED UP AND CARRIES OUT OF THE BYTE ARE DISREGARDED.
THE RESULTANT BYTE IS SENT ALONG WITH THE DATA.
ON RECEIPT THE RECEIVING DEVICE CARRIES OUT SAME CALCULATION.
THE RESULT IS COMPARED WITH THE CHECK SUM.
AND A RESEND IS REQUESTED IF THE NUMBERS DON’T MATCH - 26what is echoeing back- WHERE DATA IS SENT FROM SOURCE MACHINE TO DESTINATION.
DESTINATION MACHINE SENDS BACK A COPY TO THE SOURCE.
IF DATA DOESN’T MATCH THEN IT NEEDS TO BE RESENT.
IF IT MATCHES THEN ITS ASSUMED TO BE CORRECT - 27what is a protocol?a protocol is a set of rules that govern the communication between devices.
- 28what is the importance protocols?they define: datagrams, transfer rate, methods or error detection, algorithm to ensure successful transfer
- 29what is the Open systems interconnection model?A model consisting of 7 layers
Application layer- collects and delivers data between the presentation layer
- presentation layer; deals with formatting and presentation of data converts any data necessary for conversion encryption/decryption
session layer- overlooks the initiation. managment and termination of connection sessions. determines modes
transport layer- establishes connection with recipient. carries out packetisation and tracks packets to ensure succesful transmission. checks for errors on packet arrival and requests for resend
network layer- Source and destination IP of packets added. Packets sent to the next hop in the route on a WAN using routers.
data link layer- involves control of access, and error checking and correcting
-involves making data into format that will be sent via different media - 30what is the TCP/IPtransmission control protocol. internet protocol
A set of networking protcols that work as 4 layers that controls data transmission across network
involves Application layer (application/ presentation, session layer)
transport layer (/transport layer)
internet layer (network layer)
network access layer (data link and physical layer)
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- Highers computing (semester 2) Flashcards on networks and protocols, created by Daniel Nnajiuba on 16/05/2022.
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- Daniel Nnajiuba
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