Routing Numbers for ETNS services generally conform to international numbering standards. The structure and administration of these numbers is a national matter. It is also possible for networks involved in the carriage of ETNS calls to agree on a bilateral basis on the use of Routing Numbers that do not conform to international numbering standards.
The ETNS Registrar is responsible for the distribution of details of Routing Numbers to the networks that use this information for translation of ETNS Numbers to Routing Numbers. These Routing Numbers are obtained by those networks in which the provision of a particular ETNS service is triggered by the receipt of an ETNS call, from the national authorities responsible for telecommunications numbering plans.
17 European countries have made provision for the allocation of Routing Numbers that can be used for ETNS services.