SIP Trunking - General Requirements for Interconnecting Enterprise Networks

Based on defined User-to-Network Interconnection (UNI) as well as Network-to-Network Interconnection (NNI) types various interconnection modes are practicable. These modes allow a further description of interconnection models as well as architecture models including interconnection functions and related interfaces. Topics covered in this article comprise functional entities and related interfaces interconnecting Internet Protocol (IP) network domains as well as interfaces between these border functions. Mainly focussed functionalities are Session Border Controllers (SBC) from various vendors handling Voice over IP (VoIP) session control traffic, SIP traffic specifically. Furthermore, partial and not standardised topics belonging to sub-functions and reference points are disclosed. Prerequisites in view of the continuous work are treated of beyond analyses and classifications of standardisation even if not all open-end questions can be answered completely in subsequent studies.