Multiple DSR Application Invocation Prevention

The DSR provides a mechanism for preventing the same DSR Application from being invoked on two different DSR nodes:

• When a DSR Application does not want to be invoked a second time on another DSR, it can insert a DSR AVP called DSR-Application-Invoked containing its DSR Application ID.
• When the Diameter Routing Function searches an ART, it ignores any Application Routing Rules associated with a DSR-Application that has inserted the DSR-Application-Invoked AVP.

DSR-Application-Invoked AVP

To prevent the same DSR Application from being invoked on multiple DSRs in a network (and processing the same message twice by the same DSR Application), a DSR Application can (optionally) add to the Request message a DSR-Application-Invoked AVP containing the DSR Application ID as describe in Table 3-4.

Table 3-4 DSR-Application-Invoked AVP

Byte 1	Byte 2	Byte 3	Byte 4
AVP Code = 2468
Flags=10000000	Length = 16
Vendor ID = 323
DSR Application Id = Unsigned32

This AVP is decoded by the Diameter Routing Function before ART processing to prevent multiple invocations of the same DSR application. Any Application Routing Rule with this DSR Application ID is ignored by the Diameter Routing Function.

This AVP can be repeated in the Request to indicate different DSR Applications, but is inserted only once per DSR Application.

Insertion of a DSR Application-Invoked AVP is controlled by DSR Application-specific System Options configuration, such as:

• Allow Subsequent RBAR Invocation – Checked = Yes, Unchecked = No
• If checked, subsequent invocation of RBAR on a different DSR node in the network is allowed.