Appendix A: TSPID Explanation
This specification uses a TSPID value that may be a mystery to some readers. The protocol does not act on the TSPID in any special way, so it may appear to be a magic number. Therefore, this section is provided to aid the reader’s understanding of the TSPID but this section DOES NOT affect the above protocol in any way.
The TSPID is a unique, up to 5 character (alpha-numeric), value assigned by the TSS to each Service Registrar (SR). The TSS associates each TFN with a single SR and therefore there is a relationship with that SR’s TSPID. Accordingly, many TFNs are associated with the same TSPID. Therefore, when the TFN/TSPID is provided in the “add” event, the TFT Router can use the TSPID to map TFN routing rules that the TFT Router has configured for that TSPID (e.g. for that SR). The creation and maintenance of these routing rules is outside of this specification and coordinated between the SR and the TFT Router.
Once the TSPID reaches the TFT Router (via an “add” event), the TFT Router uses it to identify a carrier (or service provider) and the preferred messaging aggregator. Again, the TSS is not involved with the routing logic on the TFT Router and these rules are agreed upon between the SR and the TFT Router without the involvement of the TSS.
The TFT Router maps the TSPID to its own unique ID (an ID understood by the TFT Router) and publishes updates using that ID and other data as decided by the TFT Router (i.e. Name). The ID is used to identify the service-provider and its preferred messaging hub/aggregator. This is done via fields within the Name; for example, an ID 12345 with a Name of "SMSServicer – MessagingHubProvider A” tells the consumers of that information to route the messaging for that number as follows:
To SMSServicer if there is a direct-bind to that entity or
To MessagingHubProviderA for termination to SMSServicer or
To their own aggregator - who in turn uses either 1, or 2 to complete the routing.
The TFT Router does not provide explicit routing details (no email addresses or FQDNs, etc.) since the routing can be different depending on who is making the routing decision. The ID is simply an index into the consumer’s local routing table.
In a simple ENUM query, a TN (or TFN) is used to return the ID associated with it. It’s that ID that's used to determine the best route for that message.