Networks and Web Technologies Flashcards
What is a URL?
A Uniform Resource Locator. It is the full address of an internet resource. It specifies the location, resource name and usually the file type.
What is an internet registrar?
An Internet registrars hold records of all existing website names and details of those domains that are currently available to purchase.
What is a DNS?
Domain Name System. A DNS catalogues all domain names and their equivalent IP addresses.
What happens if a domain name isn’t registered in the DNS server it was requested from?
The DNS server will send a request to another DNS server to see if that server has it. This process is repeated until the domain is found or you run out of DNS servers.
What is an IP address?
Internet Protocol address. A unique address that is assigned to every device connected to the internet. It shows where the device is located on the Internet.
What is a physical bus topology?
When all the devices on the network are connected to a single cable. The ends of the cable are plugged into a terminator.
What is the advantage of a bus topology?
Cheap, as it only requires one cable and no additional hardware.
What are the disadvantages of a bus topology?(3 things)
If the main cable fails the whole network goes down
heavy traffic greatly reduces performance
No security as all devices on the network can see all of the data transmitted across it.
What are the advantages of a star topology?(3 things)
Easy to add new devices as they only need to be connected to the central device.
If a cable fails only that device losses connected to the network.
Security as messages are all sent to the central device and so can not be intercepted by other devices.
What is the disadvantage of a star topology?
If the central device goes down the whole network goes down.
What are the advantages of a mesh topology?(4 things)
The more nodes added to the network, the faster and more reliable it becomes.
If a device goes down none of the other devices are affected.
Network can handle are large amount of traffic
Data transmission is quick as data only needs to travel between the two devices communicating.
What is the disadvantage of a mesh topology?
Can be expensive to setup due to the the number of cables/wireless access points required.
Describe packet switching
The data to be sent is split up into smaller chunks called packets.
Each packet is labelled with the order they should be reassembled.
Each packet has a header and a payload.
The packets are then sent simultaneously across the internet to their destination.
The packets are then reassembled and check for missing or corrupt data, a message is then sent back asking for data to be resent or to confirm data arrived successfully.
What is a router and what does it do?
A device that connects networks together. A router reads the IP address of the destination of the data it has received, it then moves the data forward through the fastest and least congested route.
What is a gateway?
A gateway is used instead of a router to translate data packets when the network protocols being used by the network the data is going to be sent through is different to the one it came through.
