AP Networking - Unit 1 Vocab

OSI Model

Open Systems Interconnection

Conceptual Framework

Visually shows how data moves throughout networks

7 Layers

Physical Layer

First Layer

Transmits raw data bit streams over the physical medium

Data Link Layer

Second Layer

Defines the format of data on the network

Network Layer

Third Layer

Decides which physical path the data will take

Transport Layer

Fourth layer

Transmits data using transmission protocols including TCP and UDP

Session Layer

Fifth Layer

Maintains connections and is responsible for controlling ports and sessions

Presentation Layer

Sixth Layer

Ensures that data is in a usable format is where data encryption occurs

Application layer

Seventh Layer

Human-computer interaction layer, where application can access the network services

Encapsulation

Starts from Application Layer and goes through to the Physical Layer

Data is “encapsulated” into the OSI model

Decapsulation

Starts from Physical Layer and goes through to the Application Layer

Data is “decapsulating” into the Application Layer

Payload

The data that is sent

Does NOT include headers and footers

Maximum Transmission Unit

Largest packet size that can be sent

IP Header

Header added at the Data Link Layer

Contains address and routing information

Ethernet Header

Header added at Data Link Layer

Contains MAC address information for sender and receiver

TCP Header

Transmission Control Protocol

Reliability over speed

UDP Header

User Datagram Protocol

Speed over reliability