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About -> Features

Some of the features that OpenSIPS brings:

  • robust and performant SIP (RFC3261) Registrar server, Location server, Proxy server and Redirect server
  • small footprint - the binary file is small size, functionality can be stripped/added via modules
  • plug&play module interface - ability to add new extensions, without touching the core, therefore assuring a great stability of core components
  • stateless and transactional statefull SIP Proxy processing
  • support for UDP/TCP/TLS/SCTP transport layers
  • IPv4 and IPv6
  • support for SRV and NAPTR DNS
  • SRV DNS failover
  • IP Blacklists
  • multi-homed (mhomed) and multi-domain support
  • flexible and powerful scripting language for routing logic
  • variables support in script - script variables, pseudo-variables (access to the SIP messages), AVPs (values persistent per SIP transactions)
  • management interface via FIFO file and unix sockets
  • authentication, authorization and accounting (AAA) via database (MySQL, Postgress, text files), RADIUS and DIAMETER
  • digest and IP authentication
  • Presence Agent support (many additional integration features)
  • XCAP support for Presence Agent
  • CPL - Call Processing Language (RFC3880)
  • SNMP - interface to Simple Network Management Protocol
  • management interface (for external integration) via FIFO file, XMLRPC or Datagram (UDP or unixsockets)
  • NAT traversal support for SIP and RTP traffic
  • ENUM support
  • PERL Programming Interface - embed your extensions written in Perl
  • Java SIP Servlet Application Interface - write Java SIP Servlets to extent your VoIP services and integrate with web services
  • load balancing with failover
  • least cost routing
  • support for replication - REGISTER offer new functions for replicating client information (real source and received socket).
  • logging capabilities - can log custom messages including any header or pseudo-variable and parts of SIP message structure.
  • modular architecture - plug-and-play module interface to extend the server's functionality
  • gateway to sms (AT based)
  • multiple database backends - MySQL, PostgreSQL, Oracle, Berkeley, flat files and other database types which have unixodbc drivers
  • straightforward interconnection with PSTN gateways
  • dialog support (call monitoring, call termination from proxy side, call profiling)
  • XMPP gateway-ing ( transparent server-to-server translation)
  • impressive extension repository - over 70 modules are included in OpenSIPS repository


  • OpenSIPS can run on embedded systems, with limited resources - the performances can be up to hundreds of call setups per second
  • used a load balancer in stateless mode, OpenSIPS can handle over 5000 call setups per second
  • on systems with 4GB memory, OpenSIPS can serve a population over 300 000 online subscribers
  • system can easily scale by adding more OpenSIPS servers
  • OpenSIPS can be used in geographic distributed VoIP platforms
  • straightforward failover and redundancy

Page last modified on May 14, 2013, at 02:15 PM