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OSI Encapsulation: Data Wrapping Layer by Layer

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Encapsulation: wrapping data as it moves down the stack

When you load a webpage, your HTTP request ("GET /index.html") doesn't travel alone — it gets wrapped in a series of headers as it moves down through the network stack. Each layer adds its own header containing the information that layer needs to do its job: ports for the transport layer, IP addresses for the network layer, MAC addresses for the data link layer.

At the receiver, the process reverses: each layer strips its header and passes the payload up. This encapsulation model is why protocols are independent — IP works over Ethernet, WiFi, fiber, or dial-up without caring what's below it.

Packets in motion — click to inspect:

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