The Runtime Theory

Network Layers in a Request

Visualize the four network layers (application, transport, network, link, physical) and how each adds a header as a request travels to a server.

The Runtime Theory Team05 stages

trace / request.md

APPLICATION LAYERTRANSPORTLAYER (TCP/UDP)NETWORKLAYER (IP)LINK LAYER(ETHERNET/WIFI)PHYSICAL LAYER(CABLE/FIBER/RADIO)

readyThe browser creates an HTTP request with method, path, headers, and body.

Network Layers in a Request

This diagram shows how each layer of the network stack adds its own header to data as it travels from a client to a server.

The Five Layers

LayerProtocolAdds
ApplicationHTTP, HTTPSMethod, path, headers
TransportTCP, UDPPort numbers, sequence numbers
NetworkIPSource/destination IP addresses
LinkEthernet, WiFiSource/destination MAC addresses
PhysicalCable, fiber, radioRaw bits on the medium

Encapsulation

The data grows at each layer as headers are added:

plaintext
[ HTTP headers + body ]
  [ TCP header + HTTP data ]
    [ IP header + TCP data ]
      [ Ethernet header + IP data ]
        [ bits on wire ]

Trace a packet through these layers · Read: IP Addresses and Routing

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