Universite catholique de Louvain Universite catholique de Louvain This document describes the LISP Map-Versioning mechanism. This is mechanism to provide in-packet information about EID-to-RLOC mappings used to encapsulate LISP data packets. The proposed approach is based on associating a version number to EID-to-RLOC mappings and transport such a version number in the LISP specific header of LISP- encapsulated packets. LISP Map-Versioning is particularly useful to inform communicating xTRs about modification of the mappings used to encapsulate packets. Note that, in the LISP encapsulation and in the Map Records, bits used for Map-Versioning can be safely ignored by xTRs that do not support the mechanism.