Mobile number portability
Mobile number portability lets a subscriber keep a number across operators, which breaks prefix-based routing and requires a portability check.
Definitions only — a term explained here is not a service we sell.
Mobile number portability lets a subscriber keep a number when they move to another operator. The MSISDN stays the same while the serving network changes, so the prefix no longer identifies the current operator.
Why routing must check portability
The subscriber asks the new operator to port the number. The two operators coordinate a date, and the number moves while the MSISDN stays the same. A central reference database, or a set of operator queries, records which network serves it. A route that trusts the prefix then delivers to the wrong network.
Before sending a call or message, the network queries the portability data and caches the answer. Confirm how the route combines that portability dip with the HLR lookup. A stale table brings back the same misrouting. Check whether the route dips per message or uses a cached table, and test with recently ported numbers. For sender-ID registration, the receiving network's rules apply, not the original range owner's. The phone validator checks the number's format and original range holder, not the current serving network, so the live dip remains a separate service.