Key differences between Internet Checksum and Cyclic Redundancy Check; differentiate between IC and CRC;

Internet Checksum (IC) Vs Cyclic Redundancy Check (CRC)

IC and CRC are both error detection mechanisms to ensure data integrity after transmission across the network.

Internet Checksum (IC)

Cyclic Redundancy Check (CRC)

· Covers part of IP header (Network Layer), as well as TCP/UDP data (Transport Layer).

· 16-bit modulo 2 arithmetic. Also known as “hash sum”

· Done in software.

· It can detect single-bit errors (please refer below)

· Less complex.

· Very weak error detection mechanism.

· Oldest method used for data validation.

· Used in many DLL (Data Link Layer) protocols, such as Ethernet and WiFi.

· Typically 32-bit, sent as trailer. Also known as “polynomial code checksum”

· Done in both software and hardware.

· It can detect double-bit errors. (please refer below)

· Increased complexity in the computation.

· Very powerful error detection mechanism.

Bit error – in a data sequence, change of bit 0 to 1 or vice versa.

Single-bit error – change of a single bit in the entire sequence that is transmitted

Double-bit error - change of two bits of data sequence

**************