<Jeremy's IT Lab> Day3: OSI Model & TCP/IP Suite

OSI Model & TCP/IP Suite

 

Networking model:

categorize and provide a structure for networking protocols and standards

 

■ OSI Model

-> conceptual model that categorizes and standardize different functions in NW

 

Adjacent-layer interaction

• Encapsulation : 7 -> 1
• De-encapsulation : 1 -> 7

Same-layer interaction

1 - 1 or 2 -2 , 3-3...

 

PDUs: Data + header +...

 

7 Application:

-> closest to the end user

-> interacts with SW apps (web brower)

-> protocols: HTTP/ HTTPS

-> Identifiying communication partners + Synchronizing comm

-> process-to-process

6 Presentation:

-> translate data between application and network formats

5 Session:

-> Control dialogues (Sessions) between communicating hosts (ex. web browser - YouTube)

 

4 Transport:

-> segments and reassambles data

-> breaks large pieces of data which will be sent

-> host-to-host communication

-> PDU: segment

 

3 Network:

-> Logical addessing (IP address)

-> connectivity between end host on diff networks (outside of LAN)

-> provides path selection source - destination (Router)

-> PDU:  packet 

 

2 Data Link:

-> node-to-node communication (ex. PC to Switch)

-> MAC address, Switch

-> define how data is formatted for transmission

-> detects and corrects Physical Layer errors

-> PDU: frame

 

1 Physical:

-> defines physical characteristics of transfer data between devices (bits to electrical or radio signals)

-> PDU: Bit

 

■ TCP/IP Suite

-> Conceptual model and set of comms protocols used in the Internet and other networks

-> actually in use in modern networks

 

4 Application (Application + Presentation + Session)

3 Transport 

2 Internet (Network)

1 Link (Data Link + Phisical)

 

 

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Acronyms

• OSI : Open Systems Interconnection
• IP : Internet Protocol
• PDU : Protocol Data Units