IEEE 802.1AC-2016 pdf free download – IEEE Standard for Local and metropolitan area networks— Media Access Control (MAC) Service Definition.
7. Basic architectural concepts and terms The architectural concepts used in this and other IEEE 802.1 standards are based on the layered protocol model introduced by the OSI Basic Reference Model (ISO/IEC 7498-1) and used in the MAC Service Definition (this standard), in IEEE Std 802, in other IEEE 802 standards, and elsewhere in networking. IEEE 802.1 standards in particular have developed terms and distinctions useful in describing the MAC Service and its support by protocol entities within the MAC sublayer.
7.1 Protocol entities, peers, layers, services, and clients The fundamental notion of the model is that each protocol entity within a system is instantiated at one of a number of strictly ordered layers, and communicates with peer entities (operating the same or an interoperable protocol within the same layer) in other systems by using the service provided by interoperable protocol entities within the layer immediately below, and thus provides a service to protocol entities in the layer above. The implied repetitive stacking of protocol entities is essentially unbounded at the lowest level and is bounded at the highest level by an application supported by peer systems. In descriptions of the model, the relative layer positions of protocol entities and services are conventionally referred to by N, designating a numeric level. The (N)-service is provided by an (N)-entity that uses the (N-1)-service provided by the (N-1)-entity, while the (N)-service user is an (N+1)-entity. Figure 7-1 illustrates these concepts with reference to the MAC sublayer, which contains MAC entities that provide the MAC Service to MAC Service users.
7.2 Service interface primitives, parameters, and frames Each (N)-service is described in terms of service primitives and their parameters, each primitive corresponding to an atomic interaction between the (N)-service user and the (N)-service provider, with each invocation of a primitive by a service user resulting in the service issuing corresponding primitives to peer service users. The purpose of the model is to provide a framework and requirements for the design of protocols while not unnecessarily constraining the internal design of systems; primitives and their parameters are limited to (but include all of) the information elements conveyed to corresponding peer protocol entities or required by other systems (and not supplied by protocols in lower layers) to identify (address) those entities and deliver the information. The parameters of service primitives do not include information that is used only locally (within the same system) e.g., to identify entities or organize resources.
7 The primitives of the MAC Service comprise a data request and a corresponding data indication, each with MAC destination address, MAC source address, a MAC Service Data Unit (MSDU) comprising one or more octets of data, and priority parameters. Taken together these parameters are conveniently referred to as a frame, although this does not imply that they are physically encoded by a continuous signal on a communication medium, that no other fields are added or inserted by other protocol entities prior to transmission, or that the priority is always encoded with the other parameters transmitted.IEEE 802.1AC pdf download.