Tag - session layer

OSI Model Review

Lists the seven layers of the OSI model and significant aspects of each layer

OSI Model
Application Layer

  • Provides an interface between a host’s communication software and any necessary external applications.
  • Evaluates what resources are necessary and available resources for communication between two devices.
  • Synchronizes client/server applications.
  • Provides error control and data integrity between applications.
  • Provides system-independent processes to a host.

Presentation Layer

  • Presents data to the application layer.
  • Acts as a data format translator.
  • Handles the structuring of data and negotiating data transfer syntax to Layer 7.
  • Processes involved include data encryption, decryption, compression, and
  • decompression.’

Session Layer

  • Handles dialog control among devices.
  • Determines the beginning, middle, and end of a session or conversation that
  • occurs between applications (intermediary).

Transport Layer

  • Manages end-to-end connections and data delivery between two hosts.
  • Segments and reassembles data.
  • Provides transparent data transfer by hiding details of the transmission from the upper layers.

Network Layer

  • Determines best path for packet delivery across the network.
  • Determines logical addressing, which can identify the destination of a packet or datagram.
  • Uses data packets (IP, IPX) and route update packets (RIP, EIGRP, and so on).
  • Uses routed protocols IP, IPX, and AppleTalk DDP.
  • Devices include routers and Layer 3 switches.

Data Link Layer

  • Ensures reliable data transfer from the Network layer to the Physical layer.
  • Oversees physical or hardware addressing.
  • Formats packets into a frame.
  • Provides error notification.
  • Devices include bridges and Layer 2 switches.

Physical Layer

  • Moves bits between nodes.
  • Assists with the activation, maintenance, and deactivation of physical connectivity
  • between devices.
  • Devices include hubs and repeaters.

OSI Layers
OSI Model

 

OSI Model

Download OSI Download Model Chart

CCNA Exam – OSI & TCP/IP Model

Cisco CCNA Notes

 

what is Connection oriented and Connectionless

Difference Between Connection oriented vs Connection less 

Connection-oriented means that a connection (a virtual link) must be established before data can be exchanged. This can guarantee that data will arrive, and in the same order it was sent. It guarantees delivery by sending acknowledgements back to the source when messages are received.

Example

TCP is an example of an connection-oriented transport protocol.

A common example of connection-oriented communication is a telephone call: you call, the ‘destination’ picks up the phone and acknowledges and you start talking (sending data). When a message or a piece of it doesn’t arrive, you say: “What!?” and the sender will retransmit the data.

Connectionless is the opposite of connection-oriented; the sender does not establish a connection before it sends data, it just sends without guaranteeing delivery.

Example

UDP is an example of an connectionless transport protocol.

Application Layers

Host A————————————Host B

Application layer——-data————Application layer

Presentation layer—–data————Presentation layer

Session layer———–data————Session layer

Transport layer—–segments——–Transport layer

Network layer   ——packets———-Network layer

Data-link layer——-frames———–Data-link layer

Physical layer———–bits————-Physical layer

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CCNA Interview Questions

After Review CCNA course we Conclude some short Questions with Answers

CCNA Interview Question Part 1

CCNA Interview Question Part 2

CCNA Interview Question Part 3

CCNA Interview Question Part 4

CCNA Interview Question Part 5

CCNA Interview Question Part 6

CCNA Interview Question Part 7

CCNA Interview Question Part 8

CCNA Interview Question Part 9

CCNA Interview Question Part 10

CCNA Interview Question Part 11

CCNA Interview Question Part 12

CCNA Interview Question Part 13

CCNA Interview Question Part 14

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