The TCAP layer uses the SCCP connectionless transport service to deliver transaction messages to their destinations. With this service, three additional quality of service options are available to the application:
Quality of service option |
Description |
Message priority |
The application can assign a priority of 0 (lowest priority) through 3 (highest priority). |
Return option |
Allows the calling application to request that messages (transaction requests) that cannot be delivered are returned to the application with a TCAP status indication message. By default, undeliverable messages are discarded by the SCCP layer without notifying the sending application. |
Sequential delivery |
The application can request that consecutive transaction requests are delivered in order. This might be required if an application sends multiple transaction messages without waiting for a response to the first transaction request. When this option is selected, TCAP uses the SCCP class 1 connectionless service. By default, TCAP uses the SCCP class 0 service, which has no guarantee of delivery order. |
Refer to the NMS SCCP Developer's Reference Manual for information about SCCP.