Section 5 - Networks and web technologies Flashcards
Define what is meant by the term ‘URL’
Uniform resource locator - full address of an internet resource.
Location of a resource on Internet
Resource name/file type
What are internet registrars?
Hold records of all existing website names and those available to purchase.
What are internet registries?
5 Global organisations with worldwide databases that hold records of all the domain names currently issued to individuals and companies, and their details.
Define what is meant by the term ‘Domain Name System’ /DNS
Identifies the area or domain that an internet resource resides in.
Catalogues all domain names and IP addresses in a series of global directories that DNS servers can access in order to find the correct IP address location for a resource.
What happens when a user requests a webpage using a URL?
Browser requests the corresponding IP address from a local DNS. If local DNS does not have correct IP, search extended up the hierarchy to another larger DNS database.
What happens when an IP address is located?
A data request is sent by user’s computer to the location to find the web page data.
Define what is meant by the term ‘IP address’
Unique address that is assigned to a network device. Indicates where a packet of data is to be sent or has been sent from.
Define what is meant by the term ‘Wide Area Network/WAN’
Relies on third-party carriers or connections and are spread over a large geographical area
Define what is meant by the term ‘Local Area Network’
Consists of a number of computing devices on a single site or building connected by cables over a small geographical area. Hardware is usually owned by the user.
What is a Physical bus topology
All computers are connected to a single cable. Ends of cable are plugged into a terminator.
Advantages of a bus topology
Inexpensive to install
Does not require any additional hardware like star topology
Disadvantages of a bus topology
The main cable fails network data cannot be transmitted to any nodes
Performance degrades with heavy traffic
Low Security - all computer can see all data transmissions
What is a physical star topology?
Central node (switch or computer-like router transmits messages.
Switch - record of MAC addresses of each device on network identify which one to send data to.
Advantages of a star topology
One cable fails, only one station affected
Consistent performance even with heavy usage
Higher transmission speeds/better performance than bus networks
Each station has its own cable/no collisions of data
Easy to add new stations without disrupting network
Disadvantages of a star network
Costly to install - length of cable
Central point of failure - no longer transmit to any nodes
