RFC 9827: Renaming the Extended Sequence Numbers (ESN) Transform Type in the Internet Key Exchange Protocol Version 2 (IKEv2)
Recent RFCs 2025-11-06
Summary:
This document clarifies and extends the meaning of Transform Type 5
in Internet Key Exchange Protocol Version 2 (IKEv2). It updates RFC
7296 by renaming Transform Type 5 from "Extended Sequence Numbers
(ESN)" to "Sequence Numbers (SN)". It also renames two currently
defined values for this Transform Type: value 0 from "No Extended
Sequence Numbers" to "32-bit Sequential Numbers" and value 1 from
"Extended Sequence Numbers" to "Partially Transmitted 64-bit
Sequential Numbers".