Question

You receive the following data fragment: 011001111100111101111101 . You know that the protocol uses bit stuffing. Show the data after destuffing.

Short answer

The destuffed data is 011001111111011111111.

Step-by-step solution

Understanding Bit Stuffing

Bit stuffing is a technique used in data transmission where a '0' is inserted after a sequence of five continuous '1's to differentiate data from control information. The sequence '01111110' is usually a frame delimiter and isn't part of the actual data.

Identify Bit Stuffed Patterns

In the given data fragment, locate sequences of five '1's. The data is: 011001111100111101111101. We identify these sequences to look for the presence of a stuffed '0'. Notice the sequences '11111' at positions 7 to 11, 14 to 18, and 20 to 24.

Remove the Stuffed '0's

For each identified sequence of '11111' followed by a '0', remove the '0' right after these sequences. This gives us the destuffed data: 011001111111011111111.

Key concepts

Data Transmission

Data transmission is the process of sending data from one place to another. It can involve multiple systems, devices, or components communicating with each other. For efficient and accurate transmission, maintaining data integrity is crucial. This means ensuring that the data sent is exactly the same as the data received. To do this, various techniques are used to handle errors and ensure correctness.

One such technique is **bit stuffing**, which helps differentiate between data and control signals. By inserting extra bits, the protocol makes sure the communication remains organized and understandable by both sender and receiver.

• Ensures the sequence of bits is not mistaken for special control information.
• Keeps the data stream continuous and uninterrupted.

Overall, robust data transmission techniques like bit stuffing are key for reliable and effective communications.

Control Information

In data communication, control information is vital for managing and interpreting the data being transmitted. It refers to the data used by protocols to manage the setup, delivery, and flow of data. Control information helps in coordinating the start and end of data transmission.

To distinguish control information from actual data, certain patterns or sequences are used. **Bit stuffing** serves as a tool to separate these two, ensuring that patterns meant for control are not mistaken as part of the data.

• Prevents data from being misconstrued as control commands.
• Ensures synchronous and orderly data transfer.

This structure allows receivers to clearly understand and process the data without ambiguity or confusion.

Frame Delimiter

A frame delimiter is like a bookend for frames in data communication. It marks the beginning and end of a frame, which is a packet of data, within a transmitted stream. Recognizing these delimiters is crucial for correctly interpreting the received data.

For example, the sequence '01111110' is often used as a frame delimiter. In bit stuffing, the protocol ensures that this sequence doesn't appear in the actual data, so it's reserved only for marking frames.

• Helps receivers identify where a frame starts and stops.
• Aids in separating different frames in a data stream.

By using clear frame delimiters, networks can manage data transmission efficiently, avoiding misinterpretation and maintaining data accuracy.