TCP/IP stack
Layered architecture defining protocols for internet communication: physical, data link, network, transport, and application layers. TCP/IP enables global internet communication.
Real World
When you send an email via Gmail, the message passes down through each TCP/IP layer: the application layer formats it as SMTP, the transport layer segments it with TCP, the network layer adds IP addresses, and the data link layer frames it with your router's MAC address.
Exam Focus
Learn all four layers in order with one protocol per layer — examiners frequently ask you to match protocols to their correct layer.
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