OSI Reference Model ppt by TP

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Mohammad Tanvir ParvezEngineer (O&M)

Mango Teleservices [email protected]

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OSI Reference Model


Objective

The original objective of the OSI model was to provide a set of

design standards for equipment manufacturers so they could

communicate with each other.

23/17/2015 Presented By : Mohammad Tanvir Parvez


What is OSI Model ?


Open Systems Interconnection (OSI) is a set of internationally recognized, non-proprietary standards for networking and for operating system involved in networking functions.

7.. Application Layer6. Presentation Layer5. Session Layer4. Transport Layer3. Network Layer2. Data Link Layer1. Physical Layer

All People Seem To Need Data Processing

7 Layers


Layer 7 : Application Layer

The top layer of the OSI model

Provides a set of interfaces for sending and receiving applications to gainaccess to and use network services.

Ex: HTTP, FTP, SMTP

PDU : User Data

• The application layer is responsible for providing services to the user.


Layer 6 : Presentation Layer

Data formatting, translation, encryption, and compression. Ex: ASCII, HTML, JPEG. PDU : Formatted Data .

• The presentation layer is responsible for translation, compression, and encryption.


Layer 5: Session Layer

Responsible for setting up, managing and tearing down sessions betweenpresentation layer entities.

Providing dialog control between devices. It coordinates communication between systems and serves to organize their

communication by offering three different mode : simplex , half duplex , fullduplex .

PDU : Formatted Data.

• The session layer is responsible for dialog control and synchronization.


Layer 4: Transport Layer

Manages the transmission of data across a network.

Manages the flow of data between parties by segmenting long datastreams into smaller data chunks.

Can use either connectionless or connection oriented sessions. Connectionless sessions rely on upper layer protocols for error control and

are often used for faster less reliable links. Ex: UDP.

• The transport layer is responsible for the delivery of a message from one process to another.


Layer 3: Network Layer

Handles addressing messages for delivery, as well as translating logicalnetwork addresses and names into their physical counterparts.

Responsible for deciding how to route transmissions between computers. This layer also handles the decisions needed to get data from one point to the

next point along a network path. This layer also handles packet switching and network congestion control. Devices: Routers . PDU: Packet.

• The network layer is responsible for the delivery of individual packets from

• the source host to the destination host.


Layer 2: Data Link Layer The data link layer provides access to the networking media and physical

transmission across the media and this enables the data to locate its intendeddestination on a network.

The data link layer provides reliable transit of data across a physical link byusing the Media Access Control (MAC) addresses.

The data link layer uses the MAC address to define a hardware or data linkaddress in order for multiple stations

Devices: Switches, Bridges. PDU: Frame.

• The data link layer is responsible for moving frames from one hop (node) to the next.


Layer 1: Physical Layer

Defines physical medium and interfaces. Determines how bits are represented. Controls transmission rate & bit synchronization . PDU: Bits. Devices: hubs, cables.

• The physical layer is responsible for movements of• individual bits from one hop (node) to the next.


Summary



PDU’s And the OSI Model


Any Question???



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OSI Reference Model ppt by TP

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