d behaviors. 'The exception is when a resource is represented by a resource layer, e.g., as directory resources are in the Internet architecture (DNS) and in OSI networks (the X.500 directory). 2.3 Agents and Actors Messages that carry ASP information: Message Detector Generator Object Event LPM-specific reference reference identifier identifier LSM event information parameters (optional) (optional) (optional) (optional) (if any) Operation Primitive parameters Example: { connect(encoded), Request (encoded), 3.1.kHz voice (encoded), 1234566 (calledPartyNumber encoded), etc., ...} Messages that carry LPM information only: Message LPM-specific parameters for the message type notASP Fig. 2.26 General formats for messages when a layer is separated into an LSM and an LPM Since the existing DSS1 L3 standard does not define the LSM, no general approach to message formatting, data typing, and encoding has been used. Message description and encoding to the bit-level is therefore defined uniquely for a large number of message types to a great length. Also, as a result of the absence of an LSM description, there exist message types that represent several ASPs, depending on some parameter value in the message, or on who sends the message (the TE or the LE). Such a mapping dissonance makes it harder to understand and maintain the standard and complicates agent functions. Let's now take a closer look at the actor-agent interface (AAI) for control lay- ers. We saw that an LSM can have an existence only if it is contained in an LPM and if there exist an AAI in the actual layer element. We also saw that, in natural language, events in an AAI could be expressed as map <LSMeventSpecification> on the AAI of <detecting actor identifier>. An obvious observation is therefore that AAI-event types are ASPs that carry the ASPs of the LSM. We say that ASPs in such AAIs are meta-primitives, i.e., primitives that carry other primitives (a com- mon term for meta-primitives in some standards is invoke). In AMLn only two such meta-primitives are