CS 170: Introduction to Networking

Vocabulary flashcards covering the core concepts, components, ISP hierarchies, and protocol layers of computer networking from the CS 170 lecture.

Computer Network

A system that connects end systems (also known as hosts) through communication links and packet switches.

Communication Links

Physical connections and transmission channels—such as twisted copper, coaxial cable, fiber optic, and radio—that transmit data between network devices.

Packet Switch

A device that takes packets from an incoming communication link and forwards them to an outgoing communication link, primarily categorized into routers and switches.

Router

A packet switch located in the network core that operates on the Network layer to forward packets toward their destinations.

Switch

A packet switch located in the access network that operates on the Data Link layer.

Route (Path)

The sequence of communication links and packet switches traversed by a packet moving from sender to receiver.

Socket Interface

An interface provided by end systems specifying how a program on a host requests the Internet infrastructure to deliver data to a destination host, defined by an IP address and a port number.

Network Protocol

Rules defining the format and order of messages exchanged between two or more communication entities, as well as the actions taken on transmission, receipt, or other events.

Network Edge

The perimeter of the Internet composed of end systems (such as computers, smartphones, servers, tablets, and IoT devices) hosting network applications.

Access Network

The network that physically connects an end system to the edge router.

Local Area Network (LAN)

A network technology, such as WiFi or Ethernet, used to connect end systems directly to an edge router.

Network Core

The mesh of interconnected communication links and packet switches that forms the central fabric interconnecting the Internet's end systems.

Store-and-Forward Transmission

A transmission method where a packet switch must receive an entire packet on an inbound link before beginning to transmit that packet onto an outbound link.

IPv4 Address

A numerical label assigned to an end system consisting of four numbers separated by periods, with each number ranging from 0 to 255 (e.g., 162.159.135.42).

Forwarding Table

A table inside a router that maps a packet's destination IP address to one of the router's outbound communication links.

Peering

An arrangement where ISPs on the same tier connect their networks directly to pass traffic between each other without sending it up and down the hierarchy, typically without charging each other.

Internet Exchange Point (IXP)

A shared facility where networks engage in paid peering, host content providers, and utilize state-of-the-art routing and network equipment.

Internet Protocol Stack

The five-layer architectural model of Internet protocols consisting of the Application, Transport, Network, Link, and Physical layers.

Application Layer

The layer where network applications reside; its data packets are called messages, and it includes protocols such as HTTP, SMTP, and DNS.

Transport Layer

The layer responsible for transporting application layer messages between endpoints; its data units are segments, provided mainly by TCP and UDP.

Transmission Control Protocol (TCP)

A Transport layer protocol providing connection-oriented service, reliable data transmission, and flow control.

User Datagram Protocol (UDP)

A Transport layer protocol providing connectionless, unreliable transmission without flow control.

Network Layer

The layer responsible for moving datagrams from host to host across the Internet using IP and routing protocols.

Link Layer

The layer responsible for moving data units called frames across individual communication links between source and destination (e.g., WiFi and Ethernet).

Physical Layer

The layer responsible for moving individual bits across transmission media such as coaxial cable and fiber optic cable.

Encapsulation

The process by which each protocol layer wraps the higher layer's data unit with its own header, converting a message into a segment, a datagram, and ultimately a frame.