Chapter 2.1 - Networking Concepts and Models

These flashcards cover key concepts and terminology related to networking models, including the OSI and DoD models, encapsulation, and decapsulation.

Conceptual Model

A representation of a system or process used in networking to help understand end-to-end network communication.

OSI Model

A seven-layer network conceptual model created by the International Organization for Standardization (ISO) to standardize networking functions.

DoD Model

A four-layer network conceptual model commonly known as the TCP/IP model, used in the internet protocols suite.

Abstraction layer

Generalization of a system, process or device.

Decapsulation

The process of removing a header and/or trailer from data to retrieve the original data.

Encapsulation

Adding heading or trailing information to network data to prepare it for transmission.

Header

Information added to the beginning of network data before its transmission.

Trailer

Information added to the end of network data before its transmission.

Protocol data unit (PDU)

Data encapsulated with an abstraction layer's header or trailer.

Payload

The actual network data being transmitted, excluding the headers or trailers.

OSI Layer 7 (Application)

The layer where network protocols interact with a network-aware application.

OSI Layer 6 (Presentation)

The layer where data is prepared for transmission between the application layer and the session layer.

OSI Layer 5 (Session)

The layer where a data transmission channel, known as a session, is established between communicating devices.

OSI Layer 4 (Transport)

Responsible for end-to-end communication and error recovery, ensuring complete data transmission between devices.

Transmission control protocol (TCP)

A network protocol used to establish a guaranteed, connection-oriented communication channel between communicating devices.

User Datagram Protocol (UDP)

A network protocol used to provide non-guaranteed, connectionless data transport for communicating devices.

Segment

PDU created by TCP. Includes a network header called a TCP flag.

Datagram

PDU created by UDP and includes a UDP header.

TCP flag

TCP header that contains connection state information.

OSI Layer 3 (Network)

Responsible for routing and forwarding data packets across networks using the Internet Protocol (IP).

Router

Layer 3 networking device that connects at least two networks.

Routing protocol

Ruleset used by a router to determine the most efficient route to a destination network.

OSI Layer 2 (Data Link)

Provides node-to-node data transfer and framing for data packets, ensuring they are transmitted error-free across the physical layer.

Frame

PDU created by layer 2, containing data transmission parameters and physical addresses.

Logical link control (LLC)

Layer 2 sublayer providing data flow control, error detection, and error correction.

Media access control (MAC)

Layer 2 sublayer that controls how data is placed onto and received from the network medium, managing resource sharing and addressing.

OSI Layer 1 (Physical)

The lowest layer of the OSI model, responsible for the physical transmission of data over network media, including cables and signaling.

Layer 1 payload transmission - method

As a series of binary numbers on the network medium.

DoD model: Application layer

Responsible for allowing network-aware applications to interact with transmitted data. Corresponds to OSI model layers 5, 6 and 7.

DoD model: Transport layer

Handles end-to-end communication via TCP and UDP, ensuring complete data transfer and error recovery. Corresponds to OSI layer 4.

DoD model: Internet layer

Responsible for routing data across the network through logical (IP) addressing. Corresponds to OSI layer 3.

DoD model: Network access layer

Controls the physical transmission of data over the network, including framing and MAC addressing. Corresponds to OSI layers 1 and 2.