ffer(...)) gevOrder(..) Case ASPtype Reject -> createLocalPdu(sendReject(...)) locSend(in B, localSDU) Order -> createLocalPdu(sendOrder(globalSDU)) locSend(in B, localSDU) Fig. 4.27 An implementation of the use of sendOFFER An important conclusion is that the implementation algorithms for the MEH described in the previous figures are not unique for global SAP operations. They look the same for all kinds of global operations. The algorithms depend only on the fact that all global ASPs are described in the same way, which means that the parameters of gevOrder, as a minimum, identify the following information for glo- bal ASPs: The operation class, The operation name, The primitive type, The parameters, If the operation is synchronous or asynchronous. Given that a language, like AML, that includes this information is used for ASPs, and that the operations of the node platform are known, MEHs can be imple- mented by code generation (if the node platform provides reliable data transfer). This subject is treated more in depth in Sect. 5.4. Note also that each type of plat- form requires its own MEHs. Other conclusions are: Global send and receive operations (over network service interfaces) must con- sider the distributed nature of the network. Send and receive operations over platform service interfaces (local) need not consider problems caused by distri- bution. Synchronization (blocking) effects that are specified for global operations are completely independent of how these effects are defined on the local level. 4.6 Summary Summary The most important role for a physical network model of a sysnet model is to unify all model fragments that are created on lower integration levels. Thereby, it can act as an access structure to those fragments. A physical network consists of physical nodes that are related over network interfaces. A network interface relates two physical nodes. A network interface may or may not include a physical media connection. There are three views of every network interface: an external view tha