Nummerdekning

Nummerdekning refers to the system by which telephone numbers are allocated, managed, and routed within a country or region. It encompasses how numbers are organized into a national numbering plan, how blocks of numbers are assigned to service providers, and how dialing formats enable reachability for local and international calls.

It distinguishes geographic numbers, mobile numbers, non-geographic numbers, and service numbers, and it governs how new numbers are introduced, how existing numbers are renewed or recycled, and how portability is handled when customers switch providers.

Administration is typically the responsibility of a national regulatory authority, operating within international guidelines such as ITU-T E.164. The authority allocates number blocks to operators, maintains registries of active numbers, and coordinates routing with network operators. Programs may include number pooling to conserve finite resources and procedures for decommissioning unused numbers.

Why nummerdekning matters: it affects reachability, dialing simplicity, and market competition. Poor planning can lead to exhaustion of available numbers, complex dialing plans, number misrouting, or fraud. The rise of VoIP and cloud communications has driven increased emphasis on interoperability between traditional public switched telephone networks and non-traditional networks.

Related concepts include the ITU E.164 numbering plan, number portability, and national dial plans. Improvements in nummerdekning aim to balance efficient use of numbers with wide accessibility.