DATA LINK

Sir. Jetand classmates

Presented to:

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presentation about"data link"

Jericho R. Andresand 2 others

05.The future of data link

01.Introduction

04.The challenges of data link

03.The benefits of data link

02.How datalink works

TABLE OF CONTENTS

"data link"

01

introduction

OSI MODEL

1.Physical

2.Data Link

3.Network

4.Transport

5.Session

6.Presentation

7.Application

• The data link layer is the second layer of the OSI model. It is responsible for providing reliable communication between two nodes on a network.
• It ensures that data is delivered correctly and without errors.
• It also controls the flow of data between the nodes.

What is data link?

• The data link layer is essential for reliable communication over a network.
• It helps to ensure that data is not lost or corrupted during transmission.
• It also helps to prevent congestion on the network.

Why is it important?

Broadcast / | \ Device 1 -------- Router -------- Device 2 | | \ Device 3 Device 4

Device 1 ----------------------- Device 2

Point-to-Point / \

There are two main types of data link:

• Point-to-point: This type of data link connects two devices directly.

In a point-to-point data link, there is a direct connection between two devices. Only the two devices can communicate with each other.

• Broadcast: This type of data link allows data to be sent to all devices on the network.

In a broadcast data link, there is a shared connection between multiple devices. Any device can send data to all the other devices on the network.

The different types of data link

"data link"

02

How data link works

Each frame contains a header and a trailer.

The data link layer works by dividing the data into frames.

The trailer contains error-checking information.

The header contains information about the destination and source addresses, as well as the length of the frame.

The data link layer also performs error detection and correction.

If an error is detected in a frame, the data link layer will request that the frame be sent again.

The data link layer also performs flow control

• This prevents a sender from sending data faster than the receiver can receive it.

flow control in the data link layer:

• Flow control is a technique used to regulate the amount of data that the sender can send to the receiver.

• This is done by using a variety of techniques, such as stop-and-wait flow control, sliding window flow control, and rate-based flow control.

• The goal of flow control is to prevent the sender from overwhelming the receiver with too much data.
• This ensures that the data is delivered reliably and efficiently.

03

The benefits of data link

• Improved security: The data link layer can help to improve the security of the network by providing encryption and authentication services.

• Increased throughput: The data link layer can help to increase the throughput of the network by preventing congestion.

• Improved reliability: The data link layer helps to ensure that data is delivered correctly and without errors.

04

The challenges of data link

challenges of data link

security

The data link layer can be vulnerable to security attacks, such as spoofing and denial-of-service attacks.

cost

The data link layer can add cost to the network, as it requires additional hardware and software.

Latency

The data link layer can add latency to the network, which is the time it takes for data to travel from one node to another.

05

The future of data link

The future of data link

New applications:

Data link is being used in new applications, such as the Internet of Things (IoT) and virtual reality.

Emerging technologies:

Emerging technologies, such as 5G and optical networking, are expected to improve the performance and reliability of data link.

06. METODOLOGÍA

05

Noicy channel protocols

Stop-and-wait

is the simple error control and flow control technique that works by sending one frame at a time and waiting for an acknowledgment from the receiver before sending the next frame. This process continues until all frames have been sent and acknowledged. In a noisy channel, stop-and-wait can be inefficient because it can lead to a lot of retransmissions. If a frame is lost or corrupted in transmission, the sender will have to wait for the timeout period to expire before retransmitting the frame. This can lead to significant delays in data transmission.

How it works

1. The sender sends a frame.
2. The sender waits for an acknowledgment from the receiver.
3. If the sender does not receive an acknowledgment within a specified time, it retransmits the frame.
4. This process continues until the sender receives an acknowledgment for the frame.

Stop and Wait

Selective repeat

Selective repeat is a more efficient error control and flow control technique than stop-and-wait because it allows the sender to continue sending new frames while waiting for acknowledgments for previously sent frames. The sender maintains a sliding window of sent frames and can continue sending new frames as long as the number of unacknowledged frames (the "window size") is within a specified range. If the receiver receives a frame out of order or if a frame is corrupted, it discards the frame and sends a negative acknowledgment (NACK) to the sender. The sender then retransmits only the frames that were NACKed.

How it works

1. The sender maintains a sliding window of sent frames.
2. The sender can continue to send new frames as long as the number of unacknowledged frames (the "window size") is within a specified range.
3. If the receiver receives a frame out of order or if a frame is corrupted, it discards the frame and sends a negative acknowledgment (NACK) to the sender.
4. The sender retransmits only the frames that were NACKed.

Selective Repeat

Go-Back-N

Go-Back-N is another error control and flow control technique that allows the sender to continue sending new frames while waiting for acknowledgments for previously sent frames. The sender maintains a sliding window of sent frames and can continue sending new frames as long as the number of unacknowledged frames (the "window size") is within a specified range. If the receiver does not receive an acknowledgment for all frames within a specified time or if a frame is corrupted, it sends a timeout message to the sender. The sender then retransmits all the frames in the window starting from the last acknowledged frame.

How it works

1. The sender maintains a sliding window of sent frames.
2. The sender can continue to send new frames as long as the number of unacknowledged frames (the "window size") is within a specified range.
3. If the receiver does not receive an acknowledgment for all frames within a specified time or if a frame is corrupted, it sends a timeout message to the sender.
4. The sender retransmits all the frames in the window starting from the last acknowledged frame.

Go Back-N

Which protocol to use in a noisy channel The choice of error control and flow control technique to use in a noisy channel depends on a number of factors, including the channel characteristics, the network requirements, and the trade-offs between efficiency and complexity. Stop-and-wait is the simplest protocol to implement, but it is also the least efficient. Selective repeat and Go-Back-N are more efficient protocols, but they are also more complex to implement. In general, selective repeat is a good choice for noisy channels because it minimizes the number of retransmissions. Go-Back-N can be used in noisy channels, but it can lead to a lot of retransmissions if the channel is very noisy. Conclusion Stop-and-wait, selective repeat, and Go-Back-N are all error control and flow control techniques that can be used in noisy channels. The choice of technique depends on a number of factors, including the channel characteristics, the network requirements, and the trade-offs between efficiency and complexity.

Thank you!