Note

The following section is only applicable to the DSC Platform.

The NP Gateway launches custom queries to the PSX for ISUP Initial Address Messages (IAMs) that were intercepted at MTP3. SS7 messages are forwarded to the NP Gateway application through the Gateway Redirection (GWR) Application ID registration over MTP3 L4 connections on configured NAs.

Traffic Flow and Traffic Considerations

The NP Gateway intercepts MSUs based on a gateway redirection criteria at GWST.  The following three figures display the standard message flow processed by the NP Gateway application.

Ported REL Return Example

Ported IAM Prepend Example

Not Ported Example

Loadsharing of Traffic from the NP Gateway to PSX

The PSX NP Service is defined with a mandatory Primary PSX Name and an optional Secondary PSX Name. If the primary PSX is connected (licensed feature at PSX), the associated PSX query is sent in a round-robin implementation to the connected PSX Hosts. Since UDP does not guarantee delivery, the NP Gateway retransmits PSX queries if necessary. If no answer is received within the NP Gateway Transaction Timeout from when the IAM is first received, the IAM message is treated as a nonported call and is returned to the SS7 network unmodified.


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