Protocol

Protocol

1. Set of rules for communication so that devices can communicate effectively and reliably

2. Developed in layers

3. TCP/IP

   • Transmission Control Protocol/Internet Protocol
   • Layers
     • Application
       • Where the network applications function (email, websites etc.)
       • Email
         • POP (Post Office Protocol)
           • Sends the only copy of the email to your device
           • Only downloads email onto a single computer
           • Used for inbound emails
         • IMAP (Internet Message Access Protocol)
           • Sends a copy of the email to you
           • Can be downloaded onto multiple computers
           • Used for inbound emails
         • SMTP (Simple Mail Transfer Protocol)
           • Used for outbound emails
           • Goes from Client to Mail Server to Internet
           • Uses domain names
         • FTP (File Transfer Protocol)
           • Handles Uploads and downloads
           • Usually sends unviewable content
           • Can be replaced with HTTP
         • HTTP (HyperText Transfer Protocol)
           • Links websites using Hypertext Links
           • Is used to access websites on a webpage
           • Can be HTTPS for more secure connections
     • Transport
       • A connection is set up between 2 hosts, the rules are agreed (Packet size etc)
       • TCP (Transmission Control Protocol)
         • This splits or assembles the packeted data
         • Acknowledges that the data is sent, this is a form of error checking
     • Network
       • Packets are addressed/put into packets
       • Finds the route between nodes to sent the data
       • IP (Internet Protocol)
         • Addresses the source of the data/the destination of the data
         • Once the data is sent, the IP addresses are removed from the packets
     • Link
       • This is the hardware layer
         • Hubs/Switches/Device Drivers
       • Ethernet
         • A family of protocols
         • Segment, Format, Send
         • Packets are formed at the link layer
         • An ethernet cable links hardware devices
       • WiFi
         • A family of protocols
         • Made up of radio waves which pass through the air
         • The data is encrypted using WPA (WiFi Protected Access)
         • Split up into channels with a designated frequency
         • However different channels can also clash
         • Advantages
           • A remote connection so is easy to use
           • Cheap and easy setup
           • Easily Expandable
         • Disadvantages
           • Interference can occur between channels
           • Often it can be slower
           • It has a limited range
           • Can be unreliable
           • Vulnerable to hacking