Description: An entry containing information about one unidirectional or bidirectional crossconnect on the slave switch controlled via VSI. A VSI controller represents an instance of a service layer accessible to a network control application. The application creates virtual links via service requests to the controller, which in turn sends commands to the VSI slave, indicating the participating logical interfaces. Conversely, links are taken down by a reverse process. Virtual link creation and deletion come about as a result of routing decisions.