OSI model
The Open Source Interconnect (OSI) model was devised by the International Organisation for Standardisation (ISO) as a conceptual framework that characterises the communication functions of any networking system.
TCP/IP model
The TCP/IP model is a concise version of the OSI model. It contains four layers, unlike seven layers in the OSI model. The layers are:
- Process/Application Layer
- Host-to-Host/Transport Layer
- Internet Layer
- Network Access/Link Layer
Encapsulation / Decapsulation
When data is passed from each layer in OSI , it attach header info that information is known as PDU (Protocol Data Unit).
Data transfer from 7. application layer to 1. Physical layer.
When it reach to 2. Data Link layer. IT attach header as well as tailer info.
Then 1. Physical layer..data is converted to bit (1 and 0) and transfered over one to other physical layer..like router to router [gateway/ access point].
SO Encapsulation is adding header info to Datagram.
{L2,L3,L4,L5,L6,L7 [datragram] t2 }
Decapsulation is removal of header info from datagram as it moves through layer.
IOT reference Model
Data link layer addressing - MAC addressing
Data Link layer of the OSI model uses media access control (MAC) addresses to send and receive data frames.
Thanks edx.org
- IOT Network