scope:

The present document captures a set of assumptions that would help to define a set of ETSI requirements and a possible architecture for an IPX and in particular the ENUM & DNS aspects. It explains why an IPX may prove useful and provides guidelines which would apply to its use as a private, inter-operator IP backbone for ETSI TISPAN compliant networks. It is important that all potential Carriers' IPX implementations, ongoing in the market, should take account of ETSI NGN standards and specifications in order to ensure different "NGN implementations" may interoperate together.

The present document analyses a particular case of numbering and naming resolution for use by NGN Communications Providers when providing indirect interconnection as specified in ES 282 001 [18] and covers the need for a standard solution to address numbering and naming resolution implemented through an ENUM/DNS solution for this particular case.

A TISPAN IPX does not currently exist. It should not be assumed from the present document that ETSI would look to set in place an ETSI specific IPX, but the detailed requirements and approach set out within this document will ensure that ETSI is able to assess the options in moving forward. No decision on the way forward has yet been taken. However within ETSI there is strong recognition of the benefits that can be gained from adopting a combined approach with other parties providing the requirements specified by ETSI TISPAN can be accommodated.

The present document would also allow an assessment to be made against the approach that is currently planned to introduce an IPX by the GSMA.

Whilst the document details possible sub-domains that an operator may use they should only be viewed as possible examples.

The present document does not put constraints on commercial models.

The present document describes an Infrastructure ENUM that need not to be based on an Interoperator IP backbone, but it is managed by a confederation of operators also on the basis of a distributed architecture. As a consequence the applicability of the references to the Interoperator IP backbone network should be evaluated based on the operator's ENUM implementation.