| Define the internet | A network of interconnected computer networks which uses an end-to-end communication protocol |
| Explain the term domain name | Identifies an organisation or individual on the Internet
Domain names map to IP addresses, meaning they are essentially a human-friendly representation of an IP address |
| Explain how the domain name server system functions in organising domain names | A domain name server stores a table of domain names and their corresponding IP address
If a domain name server does not have a record of the domain that you are trying to access, your request will be passed to another domain name server |
| What forms the main structural basis of the internet | Cables passing under the ocean to connect different continents |
| Whats an internet service provider | a company that
provides its customers with access to the Internet |
| Define a packet | A packet is a container in which data is transmitted over networks |
| What are all the contents of a packet? | Adress for the sender
Adress for the recipient
Packet contents
Time to live
Protocol
Packet number x of y
End of packet flag
Checksum |
| Explain how packet switching is used to send a message | Message is split into multiple packets
Each packet is sent via the best route through routers
Packet is reasembled with other packets at destination |
| Explain in DETAIL how time to live works | Each packet can only pass through a finite number of hops. A packet’s time to live (or TTL) is a number that indicates how many hops the packet can partake in and is reduced by one with each hop. When a packet’s TTL expires, the packet is said to be dropped, meaning that the packet is deleted. The recipient will notice a missing packet and request that the sender transmits the missing packet again. |
| What is meant by a 'hop' in terms of packet switchin? | Every time a packet passes through a router |
| Define a router | Network device that sends packet to the receprienct via the quckest possible route |
| Define a gateway | Connecting node between two networks of different protocols |
| Where and why are routers used | In networks to send data to different places
To speed up the process of data transfer |
| Where and why are gateways used | Between networks of different protocols
To make packets conform to the new networks rules |
| State the way in which routers can enable maxmim performance | Routers hold tables with information relating to the fastest (least hops or least conjested) routes to certain devices which they frequently update so as to enable maximum performance |
| What two factors affect the route that a router can decide to give for a packet? | Least congestion
Least amount of hops |
| Describe the term 'uniform resource locator' (URL) in the context of internetworking | an address assigned to files on the Internet |
| Explain how routing is achieved across the Internet | Routers forward data packtes from one network to another
Each router stores data about the avaliable routes to the destiantion node
Looks up the destination IP addresses in its routin table to find the best router to which to forward the packet to
Routers continue to forward the packet until it reaches its destination node |
| https:// www. bbc.co.uk/ne ws/technology/index.html
What part of the URL is the protocol | https:// |
| https://www.bbc.co.uk/news/technology/index.html
What part of the URL is the extension | .html |
| https://www.bbc.co.uk/news/technology/index.html
What part of the URL is the subdirectory | /technolgoy |
| https://www.bbc.co.uk/news/technology/index.html
What part of the URL is the name of the file being requested | /index |
| https://www.bbc.co.uk/news/technology/index.html
What part of the URL is the directory | /news |
| https://www.bbc.co.uk/news/technology/index.html
What part of the URL is the subdomain | www |
| https://www.bbc.co.uk/news/technology/index.html
What part of the URL is the domain | bbc.co.uk |
| Explain the term ‘fully qualified domain name’ FQDN | a domain that specifies an exact resource and can be interpreted in only one way. |
| Explain the term IP address | Code that is assigned to every computer on the Internet and every device that
communicates on a network |
| How are domain names are organised | The domain name server (DNS) system |
| Explain why small/ rarely visited webites take longer to acess than large and freuqently visisted ones | require numerous changes of servers before a record can
be found. This makes those websites slightly slower to access than large websites |
| Whats the purpose and function of the domain service | ? |
| https://www.bbc.co.uk/news/technology/index.html
What part of the URL is the Fully Qualified Domain Name | www.bbc.co.uk |
| Explain the service provided by Internet registries | Giving every device in the world a unique IP address |
| Why are internet registeries needed | To stop devices having the same IP addresses which is a fundamental part of the functionality of the world wide web |
| What is an internet registery | An internet registry is an organisation responsible for the allocation of IP addresses |
| What is TTL | a number that indicates how many hops the packet can partake in |
| What does An FQDN always include | An FQDN will always include the server’s host name |
| Whats a sequence number? | A list of numbers linked by a rule
Encryption |
| What are the names for the 3 parts of a data paclet? | Trailer Header Payload |
| In a data packet what is inside a header | Adress for the sender
Adress for the recipient
Protocol
Packet number x of y
Time to live |
| In a data packet what is inside a trailer | Checksum
End of packet flag |
| In a data packet what is inside a payload | Actual data |
| What are the roles of a router | To examine the destination of each packet
forward packts from one network to another
manage congestion
choose an appropriate forwarding route
route packets according to desitaion ip adresss
store incoming pakcets temporarly
change link adress in packet
store and make use of routing table |
| Whats the purpose of DNS on the internet | Translate IP addresses to IP addresses |
