Data Transmission Protocols

Data Transmission Protocols

1. Emails

   • SMTP
     • Smart mail transfer protocol
     • Used to transmit data from email client to outgoing web server
     • It will establish a connection to your outgoing mail server and onces thats done the email is sent along with the recipients mail address
     • The SHTP will then use the recipients email domain to identify their SMTP server and then will try to establish a connection with it for then it to be accessed
   • POP3
     • Post office protocol
       • 3 = 3.0
     • Used for downloading emails from your mail server
     • With POP3 a connection is established between the recipients email client and their mail server. Then emails are downloaded to the email client and removed from the mail server.
     • Negative: cant access emails across multiple devices
   • IMAP
     • Internet message access protocol
     • Alternative to POP3 but allows for syncing rather then downloading them
     • Updates across all devices at the same time

2. Voice and video calls, over internet

   • SIP
     • Session initation protocol
     • Establishes connection between sender and receiver
       • Used to establish IP addresses
     • SIP signalling packet sent to establish VoIP call, once recieved it rings
   • RTP
     • Real time transport protocol
     • RTP will transmit data packets after the SIP connection has been made
     • RTP is built upon UDP because it gives no guarantee for delivery, taking no responsibility for recovering lost packets.
       • RTP is a protocol built upon the User Datagram Protocol (UDP) which is a more general data transfer protocol
   • RTCP
     • TRP Control Protocol
     • Send control packets that provide feedback on quality of data
       • Sends things like, bytes sent, packet counts, jitter, etc

3. Web pages

   • HTTP
     • HyperText Transfer Protocol
     • Transfers web pages to client so they can be rendered by browser
       • Also includes transfer of additonal related files
     • When you type a URL into your web browser and press return, a HTTP message will be created that requests for a file from the web server that the URL points to. The server will then send an HTTP response message that contains the file we requested.
   • HTTPS
     • HyperText Transfer Protocol Secure
     • Version of HTTP but it encrypts data
   • FTP
     • File transfer protocol
     • transferring files between computers over the internet
     • Using a web servers FTP address, username and password, FTP can establish a connection between a clients computer and the server. This first connection is called the control connection. Once this is established a second connection is established called the data connection.

4. Secure payment systems

   • SET
     • Secure electronic transaction protocol
     • With SET, when a purchase process is started only the purchase order is sent to the merchant website, the card details instead go to the merchants bank. This will then authorise the payment with the purchasers bank and the authorisation is returned to the merchant website to complete the transaction.
   • 3D Secure
     • It is an XML protocol that uses SSL encryption to ensure data is secure.
     • During a purchase process, when a user submits their card details for payment, the merchant website will establish if the card is enrolled on 3D secure. If so, the buyer will be directed to a 3D secure page for their own bank to authenticate the buyer. This successful authentication is forwarded to the merchant website who can then send the buyers card details and the 3D secure authentication to their own bank to authorise the payment.