Protocols and Packet Switching

Protocols and Packet Switching

1. protocols

   • IP
     • Internet Protocol
       • routes individual packets
   • FTP
     • File Transfer Protocol
       • used for sendng or retrieving files
         • to or from a remote server or computer
   • HTTP
     • HypertextbTransfer Protocol
       • used for accessing and recieving web pages in the form of HTML
         • on the internet
       • requests the web server to upload the requested wed page
         • to the user's browser for viewing
     • HTTPS
       • secure protocol
       • encrypts information
         • so it can't be understood by a hacker
   • TCP
     • Transmission control Protocol
       • breaks up messages sent over the internet
         • into small chunks called packets
         • reassembles the packets at the other end
           • deletes errors
           • resends lost messages
   • IMAP
     • internet message access protocol
       • retrieval protocol
       • dowloands message header
         • until the message is opened
         • message is left on the server
   • POP
     • Post office protocol
       • retrieval protocol
         • fetchs data from your remote mail server
       • downloads messgae to local device
         • deletes messgae from the server
   • SMTP
     • Simple Mail Transport Protocol
       • trasfers emails between remote email servers
         • cleint email software sends message
           • to an outgoing mail server
         • mail server contatcs destination mail server
           • to pass on email (using SMPT)
   • ethernet
     • family of protocols
       • responsible for sednig and recieving data
         • along a network cable
       • works over a range of speeds
     • hardware
       • specifies the performance
         • network cables, plugs and sokcets
     • data colllisions
       • when two deivces send data at the same time
         • how to deal with it
     • data format
       • format of the data pakcets sent and recienved

2. packet switching

   • four layer model
     • Application
       • Transport
         • Network
           • Link
             • physical hardware that connects two hosts
               • e.g- NIC and cabling
             • ETHERNET and Wi-fi
           • destination addresses are written on the packets
             • operated by the router
           • IP
         • creates a connection
           • between two computers or hosts
             • computers agree the communication settings and
         • TCP
       • determines the correct protocol to use
         • depending on the application
           • and what you are trying to do
       • FTP,HTTP,POP,IMAP,SMPT
   • alternative method of sending data across a network
     • data is broken into smaller parts
       • data packets
         • sent individually
         • given a packet number
           • to identify the order they are in
         • take the shortest possible route
           • travelling in different directions
       • reassembled when destination is reached
         • confirmation is sent to original computer when all data sent
         • message is sent asking for packets to resend
           • if a packet is missing or corrupted