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1. LAYERS

   • MAC address routes frames on LAN (LAYER 2)
     • devices assigned diferent IP addresses each time they connect to router
   • IP address routes packets on WAN (LAYER 3)
     • IP address can be static = useful on webservers
       • can also be dynamic - client COM
   • splitting larger problems into sub problems
     • devices can be manufactured to operate at specific layer

2. PROTOCOLS

   • CSMA/CD
     • provides error free transmission between two devices on LAN
     • TCP/IP
       • provides error free transmission between two devices + routing packets on WAN
       • HTTP
         • a client-server method of requesting HTML files
         • HTTPS
           • encryption + authentication of client-server data from web pages
           • FTP
             • send files between computers
             • SMTP
               • sends mail to mail server
               • POP
                 • used by email clients to get email from a mail server
                 • IMAP
                   • used by email clients to get email from a mail server+manage remote mail boxes

3. PACKETS

   • packet switching - method of routing packets
   • packet switching
     • more secure than other methods
       • TCP splits data into multiple packets
         • IP routes indiv. packets in diff. directions
           • TCP checks if transmission between points was successful
             • TCP sequences packets back in order at destination