AP networking

Encapsulation

The process of wrapping data with protocol information at each layer of the OSI model.

De-Encapsulation

The process of removing protocol information from the data as it passes back up through the layers of the OSI model.

OSI Model

A conceptual framework used to understand and implement the interoperability of different networking systems.

Application Layer

Layer 7 of the OSI model that deals directly with user data and application services.

TCP (Transmission Control Protocol)

A connection-oriented protocol that ensures reliable data transmission.

UDP (User Datagram Protocol)

A connectionless protocol that sends data without guaranteeing its delivery.

PDU (Protocol Data Unit)

The format of the data at each layer of the OSI model; for example, packets at Layer 3, frames at Layer 2.

Frame

A Layer 2 (Data Link) packet encapsulation that includes MAC address and error checking information.

Packet

A Layer 3 (Network) encapsulation of data that includes the IP address for routing.

Segment

A Layer 4 (Transport) PDU that contains a portion of the application's data along with TCP header information.

Bit

The smallest unit of data in computing, representing a binary state of 0 or 1.

IP Addressing

A system that assigns a unique identifier to each device on a network for communication.

MAC Addressing

A hardware identifier assigned to network interfaces for communications at the data link layer.

Layer 3

The Network layer in the OSI model responsible for path determination and logical addressing.

Layer 2

The Data Link layer in the OSI model that establishes communication on the local area network.

Layer 1

The Physical layer in the OSI model that transmits raw data bits over a communication medium.

Protocol Data Units (PDU) at each layer

Data encapsulations vary in type for each layer; data at Layer 7, segments at Layer 4, packets at Layer 3, and frames at Layer 2.

Encapsulation analogy

The process of wrapping data is compared to putting a letter inside multiple envelopes as it is sent through different layers.

Troubleshooting in the OSI Model

The OSI model helps isolate issues in network communications by separating functions into layers.

Modularity in Networking

Facilitates changes by allowing updates or replacements in one layer without affecting others.