Protocols

• Protocols


  A protocol is an agreed format, which allows two devices to communicate. Put simply, a protocol is a set of rules.
• TCP/IP (Transmission Control Protocol/Internet Protocol)


  Two protocols that combine to allow communication between computer systems on a network. IP is a protocol that sets out the format of packets and an addressing system. TCP is a protocol that allows packets to be sent and received between computer systems.
• HTTP (Hypertext Transfer Protocol)


  HTTP is a protocol than can be used to transfer multimedia web pages over the internet.
• FTP (File Transfer Protocol)


  FTP is a protocol that can be used when copying a file from one location to another via a network or the internet. It is typically used for the transfer of large files, as it allows broken communications to resume transferring a file rather than having to restart.
• Protocol stack


  Set of protocols that work together to provide networking capabilities.
• TCP/IP 5 layer protocol stack model

  TCP stands for Transmission Control Protocol and IP stands for Internet Protocol. There are five layers to this model:

  • Physical layer
  • Data link layer
  • Network layer
  • Transport layer
  • Application layer
• Physical layer


  Transmits the raw data. It consists of hardware such as switches.
• Data link layer


  Sends data from the network layer to the physical layer. It divides the data to be sent into data frames.
• Network layer


  Responsible for the addressing and routing of data. Routers belong to the network layer as they use logical addresses to direct the data from the sender to the receiver.
• Transport layer


  Ensures that data is transferred form one point to another reliably and without errors. Responsible for making sure data is sent and received in the correct order
• Application layer


  Provides interfaces to the software to allow it to use the network. Examples of software include email
• Layers and protocols

  A) Application

  B) Transport

  C) Network

  D) Data link

  E) Physical

  
• Ethernet Protocol


  At the data link layer, they describe how network devices can format data for transmission using frames and packets
• Wi-Fi Protocol


  Used for certain types of wireless networks that use 802.11 wireless protocols for transmitting data using electromagnetic waves in place of cables.
• Email Protocols 


  To use email, you must have an email client on your computer that has access to a mail server.
• IMAP Protocol


  Email protocol that stores email messages on a mail server. It stands for Internet Messaging Access Protocol. It allows the email user to read and handle email messages as though they were stored locally on their own computer.
• POP3


  Post Office Protocol 3 (POP3) is the third version of a protocol for receiving email. POP3 receives email for a client and stores it in a single file on the mail server.
• SMTP


  The Simple Mail Transfer Protocol (SMTP) is used to deliver email from the sender to an email server, or when email is delivered from one email server to another. SMTP can only be used to send emails, but not receive them.