Knowledge Base

Query on Release

The originating switch routes the call to the Donor Operator which then returns a message to the originating network indicating that the number has been ported away from that operator. The Donor Operator must track every number in its inventory and must track which numbers are ported out. In this case, the DO does not advise the originating switch of the destination route, only that the number is ported and the originating switch must therefore conduct a database query to find out where to send the call.

This plan does not require the Donor Operator to know the current operator of all of the numbers ported out from its number ranges. Once the customer leaves the Donor Operator, there is no need for the Donor Operator to be kept aware of where the customer has service.


  • No additional Donor Operator /Recipient Operator trunk ports and trunks are required.
  • Donor Operator call processing capacity is not impacted
  • Only a minor amount of SS7 signaling capacity and link usage to accommodate the inbound call.


  • Common Database required
  • Connectivity to the common database is required from all operators
  • Query of the database is delayed slightly when the call is first routed to the Donor Operator
  • All calls are processed twice by the originating operator
  • Call delay is introduced