Network Protocols

Network Protocols

1. Protocols

   • TCP/IP most important
     • TCP
       • Rules for how devices connect to network
         • Splits data into packets
         • Reassemble Packets
     • IP
       • Packet Switching
   • HTTP
     • Hyper Text Transfer Protocol
       • web browsers use to access websites
   • HTTPS
     • HTTP Secure
       • More secure HTTP, encrypts
   • FTP
     • File Transfer Protocol
       • Moves files between devices
   • POP3
     • Post Office Protocol v3
       • Retrieves email from server - deletes once downloaded
   • IMAP
     • Internet Message Access Protocol
       • Retrieves copy of email from server

2. Packet Switching

   • used by Routers
   • Direct Data
     • 1. Sending device splits data into Packets
     • 2. Router reads header, decides which way to send
     • 3. Change route depending on network traffic
     • 4. Arrive in different order, receiving device uses Packet numbers to put in right order
   • Packet switching is an efficient use of network

3. Packets

   • Data between networks split into equal sized Packets
     • Payload
     • Header
       • Destination address
       • PacketNumber
       • Source address

4. IP Addresses

   • used when sending data over the internet
     • Four Denary Numbers
     • Assigned before device can access the internet
       • Static
         • Permanent
         • Expensive
       • Dynamic
         • Different every time
         • Expensive

5. MAC Addresses

   • Unique Identifier
     • Hexadecimal
   • Assigned to all network-enabled device
     • Unique
     • Cannot be changed

6. Layers

   • Layers are groups of protocols that have similar functions
     • Self-contained
     • Serves Layer above
   • Application Layer
     • Turns data into websites etc.
       • HTTP FTP SMTP
   • Transport Layer
     • Data flow - split into packets
       • TCP
   • Network Layer
     • Used by routers to make network connections
       • IP
   • Data Link Layer
     • passes data over physical network
       • Ethernet