AQA AS Computing: 9.1 Structure of the Internet Flashcards
Internet
A network of computer networks and computers using unique IP addresses and TCP/IP.
Gateway
Connects networks that use different link layer protocols.
Router
Connects networks that use the same link layer protocols.
IP Address
A unique address that identifies a computer or other electronic device on a network.
WWW
World Wide Web; a system of interlinked hypertext documents accessed via the Internet; also called the Web.
Intranet
A private computer network used to share information or operations within an organisation.
Domain Name
A name that identifies one or more IP addresses.
FQDN
Fully Qualified Domain Name; conists of a host ID and domain name.
URI
Uniform Resource Identifier; specifies how to access a resource on the Internet.
URL
Uniform Resource Locator ; a URI that identifies a resource by its network location.
DNS Server
A server that translates fully qualified domains names into IP addresses.
Server
A software process that provides a serivce requested by a client.
Client
A software process that requests and uses services provided by the server.
Client-server model
A client software process initiates a request for a service from a sever software process, and the server responds to that request.
Protocol
A set of agreed signals, codes and rules for data exchange between systems.
Protocol Stack
A collection of protocol layers; each layer is responsible for part of the process governed by the stack.
TCP/IP protocol stack
A protocol stack for TCP/IP; it has an application layer, a transport layer, a network layer and a link layer.
Port
An address for a software process.
Socket
A combination of a host IP address and a port number.
Bidirectional
Data passes both ways at the same time.
Network Layer
Adds source and destination IP addresses to packets on their way from the transport layer to the link layer, and removes source and desination IP addresses from packets on their way from the link layer to the transport layer.
Link Layer
Handles all the physical details of interfacing with the cable, including the network interface card and a device driver.
Application Layer
Handles the details of a particular networking application, e.g. a web browser using HTTP.
Client Port Numbers
Temporary port numbers used by client processes; they lie in the range 1024 to 4095.
Well-known port numbers
Universally known port numbers used by services; they lie in the range 0 to 1023.
