1.3.3 Networks
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1.3.3 A) What is a network
two or more computers connected together with the ability to transmit data between each other
1.3.3 A) types of networks
Local area network (LAN) and wide area network (WAN)
1.3.3 A) What the char of WAN & LAN
when defining what either one of them don’t use the word network as its in the world: for example use - A group of computer connected over a small geographical area WAN - large geographical area, allow 4 comms between sites - WAN uses 3rd party connections - WAN less secure than LAN LAN - small geographical area or a single site -Lan uses connection owned by user - more secure than Wan
1.3.3 A) What are the two types of network topologys
Physical and logical topology
1.3.3 A) Explain physical and logical topology
phy - physical layout of wires and components which form thge netywork (bus, star, mesh) Logical - layout which shows how the data flow
1.3.3 A) Explain physical bus topology, adv & disadv
• all devices connected to backbone cable. ends plugged into a terminator ( see notes 4 diagram) A) inexpensive, no addition hardware D) if backbone cable fails entire network disconnects, more traffic means less performance, all computers see the data transmissions, security risk as all devices receive the data
1.3.3 A) Explain physical star, adv & disadv
• uses a central node (normally a switch), which directs data through mac address, unique to a device used to indenify each device on the network. A) consistent preformance even w/ heavy traffic, if one cable fails rest uneffected faster transmission than bus as no data colisions D) enpensive due to switch & cables if switch fails rest of network fails.
1.3.3 A) Explain physical mesh star, adv & disadv
• every node is connected to every other node, commonly found in wirsless tech A) no cable costs (if wireless), more nodes increases reliablity and speed. nodes automatically incorporated, no central switch inc speed D) wirless devices normally cost more, if they are wireded they need more wires makes it more expensive and maintaining network is difficult
1.3.3 A) What is protocols
Set of rules that allow data transmission between devices Protocols are the rules governing communication between hardware devices.
1.3.3 A) Explaining protocols HTTP/TCP/IP/IMAP/POP3/FTP
-hypertext transfer protocol, webpages rendering, encrypted version is https (s = secure) -tcp/ip (transmisson control networks / internet protcol) networking protocol routing packets thorugh network -POP3/IMAP (post office protocol 3/ internet message access protcol) mailing used for emails -FTP (file transfer protocol ) used to transfer files over network _
1.3.3 B) Define internet
a network of networks which allows global communicaion between computers
1.3.3 B) What does tcp and ip stand for
transmission control protocol and internet protocol
1.3.3 B) What is the tcp/ip stack
a stack of network protcols that work together passing packets during communicatioms
1.3.3 B) What are the stages of protcol layering in tcp/ip stack
Application layer Transport layer Network layer Link layer
1.3.3 B) What are the stages of protcol layering in tcp/ip stack Explain application layer
top of the stack that specifies what protocol needs to be used
1.3.3 B) What are the stages of protcol layering in tcp/ip stack Explain transport layer
• uses tcp to establish end-end connection, source and computer • splits data into packets lables w/ numbers, total number of packets the og data splits into ports and port number used for comm • if packet lost, request requests a retransmission of lost packets
1.3.3 B) What are the stages of protcol layering in tcp/ip stack Explain network layer
-adds sourve & destination ip address ( ip address + port number = socket address) - routers operate on this layr, use ip address to forward packets - sockets used to specify which device packets sent too and too the application being used.
1.3.3 B) What are the stages of protcol layering in tcp/ip stack Explain link layer
-connection between the network devices adds MAC address indentifying the network interface cards of sourve and reviceing computer - on same network mac is address of recipent computer or router
1.3.3 B) Why is the ip/tcp stack a stack ?
on the recipents computer these layers are looked from bottom to top. Once the destination has been reached mac address is removed by link layer. Ip address removed by network layer. transport layer removed port and reassembles the packets. finally app layer presents data to recipent in form it was requested in.
1.3.3 B) The ip/tcp stack in order at the souce and at the recipents
Source : file > app layer > transport layer > network layer > link layer recipients : link layer > network layer > transport layer > application layer > file
1.3.3 B) Char of WAN
large geographical area, allow 4 comms between sites + normally needs extra tel communications hardward. Infustructure of wan owneed by third party
1.3.3 B) Whats A DNS
Domin name system used to name and organise internet resourves. Its a hierarchy in which each smaller domina is seperatewd from the layer domin by a full stop. (leed.gov.uk)
1.3.3 B) What does TLD and 2LD stand for in terms of dns
top level domain and 2nd level domain
1.3.3 B) why is DNS used
Domina names easier to rememeber then ip address, role of dns is too translate these domains names into ip address