Which of the following fields was introduced in the IPv6 base header and has…
2026
Which of the following fields was introduced in the IPv6 base header and has no direct counterpart in the IPv4 header?
Answer: C. FLOW LABEL — ConceptProtocol versions may either rename an existing header function or introduce a new field. A direct counterpart performs the same operational role even…
- A.
VERSION
- B.
CHECKSUM
- C.
FLOW LABEL
- D.
HOP LIMIT
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Show answer & explanation
Correct answer: C
Concept
Protocol versions may either rename an existing header function or introduce a new field. A direct counterpart performs the same operational role even when the field name changes.
Comparing IPv4 with IPv6 therefore requires checking both the header diagrams and each field’s function.
Application
The IPv6 Flow Label is a 20-bit field used to identify packets that belong to the same flow for special handling. IPv4 has no field with that role, so FLOW LABEL meets both parts of the question.
Contrast
VERSION appears at the beginning of both IPv4 and IPv6 headers and identifies the header format.
CHECKSUM refers to the IPv4 Header Checksum; IPv6 removes that base-header field rather than adding it.
HOP LIMIT is the IPv6 form of IPv4’s Time to Live field, so the two names serve the same per-router lifetime function.
Cross-check and result
The standard IPv4 header diagram has Version, Header Checksum, and Time to Live, while the IPv6 base header has Version, Flow Label, and Hop Limit. The functional comparison leaves FLOW LABEL as the introduced field without an IPv4 counterpart.