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Can TCP packets be corrupted?
According to this answer, TCP packets are corrupted all the time without the checksum catching it.
Can the Internet checksum detect all bit errors?
A 16-bit sum-of-words checksum will detect all single bit errors and all error bursts of length 16 bits or fewer. It will also detect 99.998% of longer error bursts.
Can two packets have the same checksum?
The TCP checksum is two bytes long, and can detect any burst error of 15 bits, and most burst errors of 16 bits (excluding switching 0x0000 and 0xffff). This means that to keep the same checksum, a packet must be corrupted in at least two locations, at least 2 bytes apart.
What happens when a packet is corrupted?
Packets can arrive out of order. That can happen especially if two packets follow different paths to the destination. Packets can be corrupted, which means that for some reason, the received data no longer matches the originally sent data.
How are checksums used to detect an error?
A non-match indicates an error. For error detection by checksums, data is divided into fixed sized frames or segments. Sender’s End − The sender adds the segments using 1’s complement arithmetic to get the sum. It then complements the sum to get the checksum and sends it along with the data frames.
Is the 15 bit CRC checksum good enough?
Only you can answer what that point is. That said, the 15 bit CRC checksum CAN uses on every message is good enough for the vast majority of applications. CRCs can be arranged to always detect a single bit error, but it is possible to change multiple bits so that the result looks correct.
How can the CRC checksum give the position where the error?
To calculate the number of redundancy bits r required to correct a given number of data bits m. we must find a relationship between m and r. With m bits of data and r bits of redundancy added to them, the length of the resulting code is m + r.
What happens when a TCP checksum gets corrupted?
If a TCP checksum gets corrupted in transit the recomputed checksum won’t match the now corrupted checksum. Great, all fine so far. What happens when both the payload and checksum get corrupted and the recomputed checksum, whilst different to what it should be, just happens to match the now corrupted checksum?