Basic Networking Terminology

Client

A client is any device or software application that sends requests to a server to access resources or services. In everyday terms, your web browser acts as a client when it asks a web server to load a page. Clients initiate communication in the client-server model and rely on servers to respond with the requested data or functionality.

Server

A server is a computer or software system that listens for requests from clients and responds by providing resources, data, or services. Servers can host websites, store files, manage emails, or run applications that many users access simultaneously. They are typically designed to be always available, handling multiple client connections at the same time.

Host

A host is any device connected to a network that has an IP address and can send or receive data. This includes computers, servers, printers, smartphones, and any other networked device. The term is used broadly to refer to any endpoint that participates in network communication.

Package / Packet

In networking, a package (or packet) is a small chunk of data broken off from a larger message for transmission across a network. Each packet travels independently through the network and is reassembled at the destination. Packets contain both the payload data and header information, such as source and destination addresses, needed to route them correctly.

Frame

A frame is a unit of data transmission at the Data Link layer of the OSI model. It wraps raw bits into a structured format that includes source and destination MAC addresses, the data payload, and error-checking information. Frames are used to move data between devices on the same local network segment.

Bandwidth

Bandwidth refers to the maximum amount of data that can be transmitted over a network connection in a given amount of time, typically measured in bits per second (bps). Higher bandwidth means more data can flow simultaneously, which generally results in faster network performance. It is often compared to the width of a pipe: the wider the pipe, the more water (data) can flow through it at once.

Latency

Latency is the time it takes for a data packet to travel from its source to its destination, usually measured in milliseconds. Low latency means data arrives quickly, which is critical for real-time applications like video calls and online gaming. Latency is influenced by factors such as physical distance, network congestion, and the number of hops between devices.

Throughput

Throughput is the actual amount of data successfully transferred over a network in a given period of time, as opposed to the theoretical maximum that bandwidth represents. While bandwidth is the capacity of a network link, throughput reflects real-world performance after accounting for packet loss, latency, and protocol overhead. It is also measured in bits per second.

Protocol

A protocol is a set of rules that defines how data is formatted, transmitted, and received between devices on a network. Protocols ensure that different systems, regardless of manufacturer or operating system, can predictably communicate with each other. Examples include TCP, IP, HTTP, and DNS, each governing a specific aspect of how network communication works.

Port

A port is a numerical identifier used to direct network traffic to a specific application or service running on a device. While an IP address identifies the device, the port number identifies which program on that device should handle the incoming data. For example, web traffic typically uses port 80 for HTTP and port 443 for HTTPS.

Socket

A socket is the combination of an IP address and a port number, forming a unique endpoint for network communication. When two devices establish a connection, each end uses a socket to send and receive data, creating a two-way communication channel. Sockets are the fundamental abstraction used by applications to interact with the network.

IP Address

An IP address is a numerical label assigned to each device on a network that uses the Internet Protocol for communication. It serves two main purposes: identifying the host and providing its location in the network for routing purposes. IP addresses come in two versions: IPv4, which uses a 32-bit format, and IPv6, which uses a 128-bit format to accommodate a much larger number of devices.

Mac Address

A MAC address, or Media Access Control address, is a unique hardware identifier assigned to a network interface card (NIC) by its manufacturer. It operates at the Data Link layer and is used to identify devices within the same local network segment. Unlike IP addresses, MAC addresses are typically fixed and do not change as a device moves between networks.

ARP

ARP, or Address Resolution Protocol, is used to map an IP address to a physical MAC address on a local network. When a device wants to communicate with another device on the same network, it uses ARP to discover which MAC address corresponds to a known IP address. The result is stored temporarily in an ARP cache to speed up future lookups.

Transmission Media Types

Transmission media refers to the physical or wireless channels through which data travels between devices. Wired media includes twisted pair cables (like Ethernet), coaxial cables, and fiber optic cables, each with different speeds, ranges, and interference characteristics. Wireless media uses radio waves, microwaves, or infrared signals to transmit data without physical connections.