Plusnet Ensures IP Telephony Meets International Standards

Plusnet GmbH's SIP trunking services enable IP-based telephony systems to connect according to international standards. The company was among the first in Germany to offer SIP trunking solutions in 2006 under the product name "IPfonie Extended".

SIP trunking is a technology that allows IP-based telephone systems to establish many simultaneous, IP-based voice connections with a provider. Instead of individual SIP accounts for each line, a SIP trunk assigns complete number blocks and a defined capacity of simultaneous voice channels to the telephone system.

Plusnet provides two methods for SIP trunking: registration mode, which is easy to configure and suitable for small to medium-sized businesses, and "Fix-IP-authentification" or "Peering," typically used by larger systems. CEO Markus Wildner compared these methods to delivery to a P.O. box versus a physical address.

Modern telephone systems have evolved into Unified Communication and Collaboration (UCC) systems, integrating telephony with computer environments. Connecting these systems via traditional ISDN would require additional gateways. Direct SIP trunking (Direct SIP-Trunking) eliminates this need, significantly reducing complexity and costs when both the telephone system and the provider operate over IP.

Plusnet has been a pioneer in developing the SIP protocol on an open basis, closely adhering to ITU standard Q.1912.5. This collaboration with hardware manufacturers resulted in the SIP DDI protocol variant, which allows telephone systems to connect to large number blocks and enables Direct Dial In (DDI).