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THE DATA LINK LAYER:�� ELEMENTARY DATA LINK PROTOCOLS

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ELEMENTARY DATA LINK PROTOCOLS

Implementation of the Physical,Datalink and Network Layers

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ELEMENTARY DATA LINK PROTOCOLS

  1. A Utopian Simplex Protocol
  2. A Simplex Stop-and-Wait Protocol for an Error-Free Channel
  3. A Simplex Stop-and-Wait Protocol for a Noisy Channel

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ELEMENTARY DATA LINK PROTOCOLS

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Elementary datalink protocols

1.A Utopian Simplex Protocol

2.A Simplex Stop-and-Wait Protocol for an Error-Free Channel

3.A Simplex Stop-and-Wait Protocol for a Noisy Channel

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Elementary Datalink Protocols � 1.A Utopian Simplex Protocol

  1. Data are transmitted in one direction only
  2. The communication channel is error-free.

3. The protocol consists of two distinct procedures, a sender and a receiver.

4.The sender runs in the data link layer of the source machine, and the receiver runs in the data link layer of the destination machine.

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Elementary Datalink Protocols � 1.A Utopian Simplex Protocol

5.The sender sends frames continuously without waiting for acknowledgments.

6. The receiver can process incoming data infinitely fast

Limitation:

- No flow control or error handling is implemented

- Unrealistic assumptions (e.g., infinite processing speed, no errors)

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Elementary Datalink Protocols � 1.A Utopian Simplex Protocol

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Elementary Datalink Protocols � 1.A Utopian Simplex Protocol

Sender Receiver

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Elementary Datalink Protocols � 2.A Simplex Stop-and-Wait Protocol for an Error-Free Channel

- Data transmission is one-way (simplex).

- The communication channel is error-free.

- The receiver has finite processing speed.

- The sender transmits one frame and waits for an acknowledgment (ACK) before sending the next frame.

- The receiver sends an ACK after processing each frame.

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Elementary Datalink Protocols � 2.A Simplex Stop-and-Wait Protocol for an Error-Free Channel

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Elementary Datalink Protocols � 2.A Simplex Stop-and-Wait Protocol for an Error-Free Channel

Sender Receiver

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Elementary Datalink Protocols � 2.A Simplex Stop-and-Wait Protocol for an Error-Free Channel

Limitations:

- Inefficient for high-speed or long-distance networks due to waiting time.

- No error handling.

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Elementary Datalink Protocols � 3. A Simplex Stop-and-Wait Protocol for a Noisy Channel

- Data transmission is one-way (simplex).

- The communication channel may introduce errors (noisy channel).

- The sender transmits a frame and starts a timer.

- If the frame is received correctly, the receiver sends an ACK.

- If the frame is corrupted or lost, the receiver discards it and sends no ACK.

- If the sender's timer expires, it retransmits the frame.

- Introduces error detection and retransmission

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Elementary Datalink Protocols � 3. A Simplex Stop-and-Wait Protocol for a Noisy Channel

Limitations

- Still simplex (one-way communication).

- No handling of duplicate frames.

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Elementary Datalink Protocols � 3. A Simplex Stop-and-Wait Protocol for a Noisy Channel

Img source :https://www.sanfoundry.com/

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Elementary Datalink Protocols � 3. A Simplex Stop-and-Wait Protocol for a Noisy Channel

Sender Receiver

samueljohn.m@gmail.com

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Thank You

samueljohn.m@gmail.com

samueljohn.m@gmail.com