Components

CCITT/ITU-T has specified the following components:

Invoke. This component specifies the requested operation. A Begin message always includes one (or more) invokes. Continue and End messages sometimes include invokes.

TCAP Portion

Components Portion

Figure 15.1 -2 TCAP message.

Return Result, Last (RR-L). This component is a final response to an invoke. It contains the information obtained in a successful operation.

Return Result, Not Last (RR-NL). This component is a non-final response to an invoke, and contains a part of the information generated by the operation. This component is necessary because the maximum length of a message signal unit (MSU) is 272 octets. Since the MSU contains the component, and information for TCAP, SCCP, and MTP, the maximum length of a component is about 240 octets. Most operations yield information that fits within one component. If the information is too voluminous, it is segmented, and carried in one or more RR-NL components, and a final RR-L component.

Return Error. This component is a final response to an invoke, and indicates that the requested operation was executed, and has failed.

Reject This component is a final response to a received component. It indicates that the component cannot be processed, because its syntax is not correct.

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