protocols Flashcards
FTP - File Transfer Protocol
Provides the rules for file transfer between computers
Used to transfer files too large for attachment to emails
HTTP - Hypertext Transfer Protocol
Provides the rules to be followed by a web browser and a web server when requesting and supplying information
Used for sending requests to a web client (a browser) to a web server and returning web content from the server back to the client
What are protocols?
The rules that computers must follow when they are communicating and sending/receiving data over a network
HTTPS - Hypertext Transfer Protocol Secure
Ensures that communications between a host and client are secure by encrypting communications
SMPT - Simple Mail Transfer Protocol
Provides the rules for sending email messages from client to server and then from server to server until it reaches its destination
POP - Post Office Protocol
Used by a client to retrieve emails from a mail server. All of the emails are downloaded when there is a connection between client and server
IMAP - Internet Message Access Protocol
Messages do not have to be downloaded, but can be read and stored on the mail server. This is better for users with many different devices as they can be read from all devices rather than being downloaded to just one
What are layers?
Levels that the protcols of the TCP/IP stack are organised into through which all data must pass
Application layer
Provides services to applications such as web browsers and email clients. This is where requests are made to web servers or emails are sent
Protocols:
- FTP
- HTTP
- HTTPS
- SMPT
- POP
- IMAP
Transport layer
Divides data sent from the application layer into packets. Checks that data has been received and notifies sender if it has
Protocols:
- TCP
- UDP (User Diagram Protocol)
Internet layer
Adds the source and destination IP addresses to the data and routes it to the recipient computer
Protocols:
- IP
Network layer
Uses network-specific protcols to ensure correct transmission of data through the local network
Protocols:
- Ethernet Protocols
- Wi-Fi Protocols
What’s in a packet?
- Payload (data being sent)
- Destination address (IP address)
- Source address (IP address)
- Packet number (x out of y)
- Check digit
TCP/IP - Transmission Control Protocol/Internet Protocol
A set or stack of protocols that allows a computer to communicate across a WAN
The protocols:
- split the data into smaller packets, reassemble packets on arrival and encrypt/decrypt as required
- add an address in order to transmit the data to the correct destination
- notify the sending computer that the data has been received
