Arithmetic Checksum

Arithmetic checksum is a method used to detect errors in data transmission by performing a numerical sum of the data and including the result with the transmission. Here’s how it works:

Overview

• Usage: Commonly used in protocols like TCP and IP on the Internet.
• Process:
  • Conversion: Convert characters to numeric form.
  • Summation: Sum the numeric values.
  • Transmission: Include the sum (or its manipulated form) with the data.

Example

1. Data: 4 bytes with values 56, 72, 34, and 48.
2. Summation: Calculate the total sum:
   • ( 56 + 72 + 34 + 48 = 210 )
3. Manipulate Sum: Simplify the sum to fit a specific format, e.g.,
   • ( 210 \rightarrow 2 + 10 = 12 )
4. Transmission: Send the data along with the checksum value 12.
5. Receiver: Performs the same summation and manipulation to verify the checksum.

Limitations

• Detection: While arithmetic checksum improves error detection over simple parity, it still may not catch all errors.
• Need for Improvement: Cyclic Redundancy Check (CRC) offers a more robust error detection method.

Summary

• Arithmetic Checksum: Converts data to numeric form, sums it, and includes the result with the transmission.
• Limitations: Not entirely foolproof; may not detect all types of errors.

Next Step: Explore Cyclic Redundancy Check (CRC) for a more reliable error detection technique.