SIP Express Router Supports Secure Inter-domain Peering TransNexus Contributes OSP Support to SER

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The SIP Express Router now supports secure inter-domain peering using public key infrastructure services enabled by the Open Settlement Protocol. The new feature simplifies wholesale VoIP interconnection and reduces fraud risk.

TransNexus has contributed a new open source software module to the SIP Express Router (SER) which adds support for the Open Settlement Protocol (OSP). The new module enables SER to use secure public key infrastructure (PKI) services for secure inter-domain peering.

With the new module, VoIP operators using SIP Express Router can:

  •     Generate a public/private key pair for their SIP Express Router
  •     Obtain a signed certificate from a certificate authority
  •     Send encrypted peering requests to OSP servers
  •     Validate digitally signed access tokens for inter-domain peering
  •     Report encrypted, standards based accounting records to OSP servers

The business benefits for wholesale VoIP carriers from these new features are:

  •     Capital expense and bandwidth savings - secure inter-domain peering does not require a session border controller.
  •     Lower operating costs and reduced fraud risk - inter-domain access control based on PKI authentication is more secure and simpler than maintaining IP access lists.
  •     Lower administrative costs and faster revenue collection - secure call accounting, with non-repudiation of call detail records, eliminates interconnect settlement billing disputes.

The new module for the SIP Express Router is available from and may be used with open source OSP servers such as the OpenOSP or RAMS servers, available from The module has also been tested exhaustively and deployed using the TransNexus Peering Server. The Open Settlement Protocol is an IP operations and billing support systems protocol defined by the European Telecommunications Standards Institute (ETSI), OSP is officially known as ETSI Technical Specification 101 321 for inter-domain pricing, authorization and usage exchange.

About TransNexus

TransNexus has been an innovator of commercial and open source VoIP Operations and Billing Support Systems (OSS/BSS) since 1997. TransNexus is an active contributor to SIP Express Router, Asterisk and The TransNexus OSS/BSS solution provides wholesale VoIP carriers with an immediate increase in net profits. Key features include Least Cost Routing, Quality of Service Routing, PKI services for secure inter-domain peering, traffic analysis and control, new revenues from wholesale services, and lower cost back-office operations.

Contact: Alcina DeFigueiredo at alcina.defig @

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