vide support for temporary service elements in a logical node is through connections that are provided by a connection-oriented CSP (e.g. a virtual circuit service). This requires that the integrator manages multiple connec- tions in communication with the CSP. A generic model for logical nodes that use such a service looks as shown in Fig. 5.17. Logical node Integrator intCEI extCEI CON-CSP Fig. 5.17 The connection handling model for a logical node 5.3 Discrimination The properties of this model are as follows: The logical node is connected to the CSP over a CON-SAP and a over a CSI for connection control. The integration function in the node consists of a SAP handler (SAH) and a con- nection controller (CC). Connections are temporary. Connections are ordered, offered and removed through communication between the CC and the CON-CSP. When no connections are established over the SAP, no service elements exist in the node (they might, however, exist on the node platform, i.e. in the P-dimen- sion, but not in the DC-plane). The CC might support translation between global titles (GT) and addresses (SAPIs). The CC also establishes internal connection endpoints (intCEI) between the SAH and service elements, and relates intCEls to the external connection endpoints (extCEl) that are used between the logical node and the CSP. The reason for sep- arating internal from external CEIs is that the internal interfaces can also be made usable for CNL-CSPs. Neither the CC nor the SAH terminate any messages. SAH translates between extCEls and intCEls and performs discrimination of data flows based on CEIs. No discrimination protocol is necessary, since the CSP provides the extCEI for incoming messages, and the service elements provide the intCEls for outgoing messages. All service elements must terminate the same protocol (PRA in Fig. 5.17). This is because there is no mechanism in the integrator to instantiate a specific type of service element. Therefore the model suits cases where the logical node must handle many transactions 