# Supplementary service participants

Three parties are identified in the activation or invocation of a supplementary service:

Participant | Description
Served user | The user or node that activates or invokes the supplementary service. If the service is billable, then this is the user or node charged for it.
Originating user | The user or node that originated the call into the network.
Diverted-to user | In call forwarding services, this is the user or node to which the call is rerouted.