lRef. ASi->As control T-ROa As-RB I-invRep(ASi,...) actor REi(TEl) REdef where APi=SAPI in LAPD SAPI=0 and CHi=TEI in LAPD LAPD layers (NWi) Call-handling logical node in a local exchange (LE) In the send scenario (triggered by an r-invOrd): The agent uses the ASik>callRef table for mapping between the association iden- tifier (ASi) used in the SAG and in the message protocol (the callRef). It uses the T-AS table to identify the TE actor (by an As) that handles the actual call (identified by an ASi). It uses the As as an entry to the T-ROa table to get the route endpoint identifier (REi) for the route to the actual TE. It uses the T-RE table to find which LAPD network to use (NWi), and which address parameters (APi, CHi; in LAPD called SAPI and TEI). The agents on the TE side of the DSS1 L3 layer need no tables at all. B2 Association Operations (in SAG) AMLn defines four operations for handling associations, shown in their context in the model below. Association protocol Actor Agent Agent Actor acAssReg agAssOff acAssReq agAssAcc acAssRef agAssRej invokes are used in this phase agRelRep agRelRep acRelOrd agRelRep The essential parameters of these primitives are the association identifier (ASi) and the actor address (AA). Since creating an association is a negotiation procedure between two actors, other parameters may exist as well, e.g., parameters for authentication and parameters for abstract protocol compatibility checking. The association identifier is (strictly speaking) a parameter of the association protocol, which implies that local association identifiers may be used in SAGs (disregarded here, however). The four operations are: Operation is: actorAssociation (acAss) Primitives are: Request(destAA,ASi,...) Confirm(ASi,..) Refuse(ASi,...) Operation is: agentAssociation (agAss) Primitives are: Offer(origAA,ASi,..) Accept(ASi,...) Reject(ASi,...) Operation is: agentRelease (agRel) Primitives are: Report(ASi causedBy{agentLayer,remoteActor},...) Operation is: actorRelease (acRel) Primitives are: Order(ASi,..)