The CALL signal signals the calling of a service by another service.

An example of signaling during the invocation of a service call.

S1 EMIT    CALL
S1 RECEIPT SUCCEED

An example of signaling during the execution of a service request that involves another service.

S1 EMIT    START
S2 EMIT    CALL
S2 RECEIPT SUCCEED
S1 EMIT    SUCCEED
S1 EMIT    STOP

An example of signaling from the perspective of both ends in a service-to-service interaction.

S1 CONTEXT          |  S2 CONTEXT
------------------------------------------
S1 EMIT    START    |    
S2 EMIT    CALL     |    
                    |  S2 EMIT    START
                    |  S2 EMIT    SUCCEED
                    |  S2 EMIT    STOP
S2 RECEIPT SUCCEED  |
S1 EMIT    SUCCEED  |
S1 EMIT    STOP     |

An example of signaling from the perspective of both ends in a service-to-service interaction in which the service name was transferred with the request payload.

S1 CONTEXT          |  S2 CONTEXT
------------------------------------------
S1 EMIT    START    |    
S2 EMIT    CALL     |    
                    |  S2 EMIT    START
                    |  S1 RECEIPT CALL
                    |  S1 EMIT    SUCCEED
                    |  S2 EMIT    SUCCEED
                    |  S2 EMIT    STOP
S2 RECEIPT SUCCEED  |
S1 EMIT    SUCCEED  |
S1 EMIT    STOP     |