This recommended practice defines a message exchange framework based on information elements (IE) as a transport method for KMP datagrams and guidelines for the use of some existing KMPs with IEEE Std 802.15.4?1. This recommended practice does not create a new KMP. This recommended practice describes support for transporting KMP datagrams to support the security functionality present in IEEE Std 802.15.4. Significant in support of KMP transport is the definition of a general purpose multiplexed (MPX) data service supporting fragmentation@ re-assembly@ and protocol dispatch for payloads unable to fit in a single MAC frame.