computing networks

what is a protocol

a set of rules followed to allow two devices to communicate

purpose of Ethernet

communications and data transfer

what is Ethernet

Ethernet is a family of related protocols

purpose of Wi-Fi

communications and data transfer

what is Wi-Fi

Wi-Fi is a family of related protocols and is a trademark for the technology that allows electronic devices to connect to a wireless LAN (WLAN)

what is the generic term for networks of Wi-Fi’s nature

WLAN

how do Wi-Fi compatible devices connect to the Internet via a WLAN and a Wireless Access Point

the WAP receives data from a network via its physical connection. The transmitter converts this data into radio waves which are transmitted . Devices on the network receive these radio signals via a Wi-Fi adaptor which allows it to communicate or download data from the data source

purpose of Transmission Control Protocol

Communications over a LAN/WAN

purpose of Internet Protocol

Communications over a LAN/WAN

use of IP

identifies the location of a device on the internet and routes individual packets on a WAN via routers

use of TCP

provides an error free transmission between two routers by defining how messages are broken up into packets and reassembled at the destination. Also detects errors and resends lost packets

purpose of User Datagram Protocol`

communcations over LAN/WAN

use of UDP

uses a simple connectionless transmission model where computer applications send messages(datagrams) to other hosts on an IP network. Has no error checking or correction and maintains an open connection between the sender and recipient- faster and so used in online gaming

purpose of HTTP (Hypertext Transfer Protocol)

Webpage Requests - requests the web server to transmit the requested web page to the user’s browser for viewing

use of HTTP

used for accessing and receiving web pages in the form of HTML files on the internet

purpose of HTTPS

serves the same purpose as HTTP, but encrypts the information for more secure transactions

use of HTTPS

bank transactions

purpose of File Transfer Protocol

to transfer computer files between a client and a server on a computer network

use of FTP

used for uploading web pages and associated files to a web server for hosting

purpose of Internet Messaging Access Protocol (IMAP)

stores email messages on a server but allows users to view and manipulate the messages as though they were stored locally on their own computers. Users can organise messages into folders, flag messages as urgent and save drafts

use of IMAP

users use IMAP for receiving emails

purpose of Simple Mail Transfer Protocol (SMTP)

sending out emails from a client or relaying and forwarding emails from one mail server to another

use of SMTP

mainly used for sending emails

which protocols are in layer 1 (application)

HTTP, HTTPS, FTP, IMAP, SMTP

which protocols are in layer 2 (transport)

TCP, UDP

which protocols are in layer 3 (internet)

IP

advantage of the four layer model

lets suppliers easily adapt the protocol software to the specific hardware and OS

how does the four layer model work

packets of data are passed down through the layers which each perform their individual functions before it is transmitted across the network

what is the role of the application layer

it is where the network applications (eg web browsers, email programs) operate. The data is encoded so it is understood by the recipient

what is the role of the transport layer

it sets up the communication between the two hosts and establishes settings such as size of packets

what is the role of the Internet layer

addresses and packages data for transmission. Routes packets across the network. It attaches the IP address of the sender and the destination

what is the role of the link layer

It is where network hardware (NIC) is located. OS drivers also sit here

example of link layer job

It attaches the MAC addresses of the sender and the recipient, allowing the packet to be directed to a specific device on a LAN