Which statement accurately describes how IPv6 handles checksums?

• A. IPv6 uses a header checksum identical to IPv4
• B. IPv6 includes a header checksum in extension headers
• C. IPv6 uses a checksum in the extension header
• D. IPv6 does not have a header checksum; integrity is provided by upper-layer protocols

Answer: (C)

IPv6 does not include a header checksum in the IPv6 header or in any extension header. The network layer was designed to be processing-friendly by removing a checksum, so integrity is handled at higher layers. Transport-layer protocols like TCP and UDP provide checksums that cover a pseudo-header (including source and destination addresses, the protocol number, and the payload length) plus the payload itself. This means errors affecting IP header fields are detected by the transport-layer checksum rather than by an IP header checksum. Extension headers are not equipped with their own checksums either. So the accurate idea is that IPv6 relies on upper-layer checksums for integrity, not a header checksum at the IP layer.