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SCCP/TCAP Call Flows

Overview

This section shows examples of normal and abnormal SCCP/TCAP message flows. These diagrams are intended to show the protocol aspect of the flow correlating with the host messages. It is not a complete list to cover all the cases. More complete SCCP and TCAP call flows can be found in ITU SCCP and TCAP test specifications.

Host Using SCCP Connectionless Service Directly

These call flows show the normal and abnormal cases when the host uses the SCCP service directly (TCAP service is not used). Only the SCCP peer level service is shown here.

Success

SCCP successfully sends the UNIT-DATA message to the network and informs the host about SCCP receiving the Unitdata message from the network.

SCCP Connectionless Service Direct - Success

Message Returned

SCCP sends the UNIT-DATA message to the network and sets the return option in the Quality of Service parameter. In this case, the message cannot be delivered to the destination due to failures on the network (such as, a Global Title is translated to an unavailable DPC). The message is returned and the host is informed by an N_NOTICE Indication primitive in a PPL Event Indication message.

SCCP Connectionless Service Direct - Message Returned

Host Using ITU TCAP Service

The following diagrams show examples of the host using TCAP services. Note that using TCAP service implies the use of SCCP service in the current implementation.

One Transaction/ One Invocation

The services of each SS7 protocol level is used when the host initiates a single transaction with a single remote invocation. In this case, the transaction is successfully completed and the remote operation is successfully invoked.

Host Using TCAP Service - 1 Transaction, 1 Invocation (ITU)

One Transaction, Two Invocations

The host uses ANSI SCCP/ TCAP services, while one transaction is created and completed successfully, two remote operations are successfully invoked. Only TCAP peer-level services are shown. The SCCP and MTP services are similar to the previous example.

Host Using TCAP Service - 1 Transaction, 2 Invocations (ANSI)

See Transaction Capability Application Part.
International Telecommunications Union (UN)
A computer, attached to the Excel platform through an RS-232 or Ethernet link, from which you run the telecommunications application that controls the Excel platform.
Destination Point Code
See Programmable Protocol Language.
See Signaling System Number Seven.
American National Standards Institute. ANSI administers and coordinates the U.S. voluntary standardization and conformity assessment system for the
telecommunications industry. More details on these standards may be
viewed at www.ansi.org.
See Message Transfer Part.