Operator-independent public user identities for IP multimedia communication services for enterprises

This paper describes usage of operator-independent Public user identities (PUI) for IP multimedia communication services for enterprises. This is a particular relevant topic for enterprises that wish to use their own domain name for public identification for (IMS based) communication services. Whereas usage of enterprises-specific domain names is common for services like mail and HTTP, it has some specific challenges for IMS based multimedia communication. These challenges include, among others: - uniform domain name for multimedia communication and other IP service, e.g. mail and http, without being tied to a single enterprise domain name administrator; - multi-IMS network subscription (within one country or across multiple countries); - non-country specific enterprise top level domain name (for example regional (e.g. .eu) or global (e.g. .com, .org) domain name); - real-time aspect of IMS services (as opposed to mail and http, which are not real-time). It is foreseen that flexibility in usage of operator-independent domain names will play an important role for uptake of IMS as communication enabler, especially for using ´name based URI´. This issue may have spin-off in the enterprise market and machine-to-machine market as well. Although the principle of operator-independent PUI is explained and elucidated within context of IMS, the principle is equally applicable for non-IMS IP multimedia networks. The present paper describes the dilemmas, describes the ongoing standardization work (3GPP; ETSI) and industry initiatives (GSMA) in this area and presents network architecture that offers solutions.