Networking: OSI Model and Topologies

A seven-layer conceptual model describing how network communication works.

Physical Data Link Network Transport Session Presentation and Application.

Transmits raw bits through physical media such as cables and wireless signals.

Handles local network communication framing and MAC addressing.

Handles logical addressing and routing between networks.

Provides end-to-end data delivery using protocols such as TCP and UDP.

Establishes manages and terminates communication sessions.

Handles data formatting translation encryption and compression.

Provides network services used by applications.

A network layout in which devices connect to a central switch or hub.

A network layout in which devices share a single main communication cable.

A network layout in which devices connect in a circular path.

A network layout in which devices have multiple connections to other devices.

A failure in one individual device connection generally does not affect other devices.

Failure of the central switch or hub can disrupt the entire network.

IEEE 802.11n; supports 2.4 GHz and 5 GHz frequencies.

IEEE 802.11ac; primarily operates on the 5 GHz frequency band.

Both use IEEE 802.11ax; Wi-Fi 6E additionally supports the 6 GHz band.

IEEE 802.11be; supports 2.4 GHz 5 GHz and 6 GHz bands.

Not Found; the requested webpage or resource could not be found.

200 means OK 301 means permanently moved 400 means bad request 401 means unauthorized 403 means forbidden 404 means not found 429 means too many requests 500 means internal server error 502 means bad gateway 503 means service unavailable and 504 means gateway timeout.