Abstract: A system or method for determining if a telephony network number is ported for use with variable numbering plan comprising, a first network node for receiving a number message comprising at least a first part of a dialled number identifying a called party, and a number portability database, containing routing numbers associated with entries in the database. The first network node is configured to compare the number message with entries in the number portability database. The first network node is configured such that if the number message or a first part of the number message uniquely matches with the whole of an entry in the database and does not match with part of another entry in the database, the first network node determines that a best match has been found. In this case, the first network node routes a call to a second network node identified by the routing number associated with the entry.

Abstract: A system or method for determining if a telephony network number is ported for use with variable numbering plan comprising, a first network node for receiving a number message comprising at least a first part of a dialled number identifying a called party, and a number portability database, containing routing numbers associated with entries in the database. The first network node is configured to compare the number message with entries in the number portability database. The first network node is configured such that if the number message or a first part of the number message uniquely matches with the whole of an entry in the database and does not match with part of another entry in the database, the first network node determines that a best match has been found. In this case, the first network node routes a call to a second network node identified by the routing number associated with the entry.