Networking Beginner

What is OSI Model?

The seven-layer Open Systems Interconnection model that standardizes network communication functions from physical transmission to application protocols.

The OSI model divides networking into seven abstraction layers: Layer 1 Physical (cables, signals), Layer 2 Data Link (Ethernet frames, MAC addresses), Layer 3 Network (IP packets, routing), Layer 4 Transport (TCP/UDP segments, ports), Layer 5 Session (connection management), Layer 6 Presentation (encryption, compression), and Layer 7 Application (HTTP, DNS, SMTP). Each layer serves the layer above it and is served by the layer below. While the internet primarily follows the simpler TCP/IP model (4 layers), the OSI model remains the standard framework for discussing and troubleshooting network issues by layer.

A network protocol used for diagnostic and error reporting, including ping and traceroute functionality.

SSL/TLS Certificate

A digital certificate that authenticates a website identity and enables encrypted HTTPS connections.

Bandwidth

The maximum rate of data transfer across a network connection, measured in bits per second.

Firewall

A network security system that monitors and controls incoming and outgoing traffic based on predetermined rules.

SDN (Software-Defined Networking)

An approach that separates the network control plane from the data plane, enabling centralized, programmable network management.

NAT (Network Address Translation)

A method of mapping private IP addresses to public IP addresses, allowing multiple devices to share a single public IP.

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