Since 1995, a group of former students of the SIP co-inventor, Prof. Schulzrinne, undertakes active research in the VoIP area at Fraunhofer FOKUS (formerly known as GMD) in Berlin, Germany. The effort of the working group led by Dorgham Sisalem results in scientific publications, proof-of-concept SIP implementations and consultancy to early industrial adopters of the technology. Jiri Kuthan’s introductory VoIP webpage hosted by FOKUS begins to be one of the most frequently cited source of information on SIP.
First Line of Code
In September 2001, first line of code of the SIP Express Router (SER) is written by Andrei Pelinescu-Onciul. By then, its routing feature was implemented using table-based first-match-first-found technique soon to be replaced by SER’s routing language and enhanced by module interface for more rapid feature introduction. The working group’s results are presented on a new website, http://iptel.org.
Development is boosted by numerous newcomers joining in 2001 through 2003, many of those students to graduate later in FOKUS. Extensions to SER are being developed by Alex Hoffmann, Bogdan Iancu, Daniel Mierla, Jan Janak, SER’s media counterpart SIP Express Media Server is built by Raphael Coeffic, Uli Abend, and Stephan Sayer; Nils Ohlmeier’s SIPSak diagnostic utility begins to climb open-source charts, and SERweb user interface appears courtesy of Karel Kozlik. SER goes to the SIP Interoperability Events (known formerly as bake-offs).
SER Goes Public
In September 2002, the code is publicly released under GPL. Same year, the first third-party contribution follows (ENUM module by Juha Heinanen).
2003 is the year of adoption: People keep working on better and faster code. SER becomes leading open-source SIP proxy server and is quickly adopted by numerous SIP services, FWD and sipphone being the best known by then. New contributors emerge (Maxim Sobolev contributes the nathelper module, Miklos Tirpak, later to join iptel, contributes the permissions module, Ramona Modroiu adds xlog and pdt modules).
Going Out of The Lab
In 2004, SER is no longer lab work. It is a fully fledged SIP server adopted by numerous ISPs. In Germany, freenet and sipgate are the first adopters, other commercial services based on SER begin to emerge worldwide. The working group migrates from FOKUS labs to a new company,
iptelorg based in Berlin, Germany. Iptelorg GmbH serves the commercial users of SER software. The number of open source contributions grows up. Iptelorg GmbH receives the rights to commercial use of the copyrights (similar to the dual licensing of mysql) and develops commercial
extensions and other SIP-related products for the professional SIP market. At the same time open-source community keeps benefiting of SER maintenance and development resulting from company’s commercial activity. Copyright to modules and code developed by 3rd parties outside FOKUS is kept by their respective owners.
The independent website iptel.org hosts the open-source SER, the free SIP service, and general SIP information. It is generously sponsored by several supporters including Fraunhofer FOKUS, iptelorg GmbH, and numerous individuals from the open source scene.
SER – Getting Started
Also in 2004, a documentation effort known as SER – Getting Started is started by three SER users from two continents. In first-half 2005, the first issue is made available describing how to get started with SER and best practices for seri.cfg, the configuration “language”. ONsip.org is started to host the documentation effort, FAQs, how-tos, and links.
Three developers, Bogdan Iancu, Daniel Mierla and Ramona Modroiu, launched a SER fork known as OpenSER, succeeding over the time to build a strong community around the project, ensuring solid development cycles, new functionalities, flexibility and documentation. New developers came on board, with relevant contributions, such as Henning Westerholt (carrierroute), Andreas Granig (path), Klaus Darilion (dialog info presence) or Ovidiu Sas (sdp).
Acquisition of iptelorg GmbH
In 2005 corporate development is going on. iptelorg GmbH opens up a new development site in Prague, Czech Republic, with primary focus on development of SIP infrastructure for mobile service providers. Later this year, iptelorg.com, the commercial activity is bought by its customer, Tekelec.
Expanding the team: Mid-2006, representatives of iptel.org and ONsip.org agree to merge as the efforts of iptel.org and ONsip.org are overlapping. ONsip.org needs access to developers to produce good documentation and iptel.org needs better documentation.
New iptel.org: September 2006, the new combined effort iptel.org site is launched.
Next Generation SER
In November 2006, a new release of SER, codenamed Ottendorf, addresses many structural shortcomings of previous SER based on experience with large-scale deployments. The release incorporates feedback from open source users and iptelorg.com customers. The key changes include update to SER’s data model, rewriting of the important timers, TCP implementation, introduction of selects to address parts of SIP messages, as well as scalability and lots of bug fixes.
OpenSER faced trademark issues and the project was renamed to Kamailio at the end of July 2008.
In August, the project forks again. The new forked project is called OpenSIPS and was created by Bogdan Iancu.
The SIP Router Project
The open source SIP server market is dominated by the flavors of SIP Express Router. However, as each projects targets more or less same application type – SIP Signaling Server – many cannot easily decide which one to pick up and be sure is the right for its needs. It is also a big concern about which project will develop the most over the time.
Many developers believe the existing situation harms all projects and the community. Several discussions were initiated during the summer of 2008 to create a reliable environment for all involved: developers, business and community.
In an attempt to reconcile the situation, we approached developers from all three projects in order to see if we can somehow merge our efforts again and provide a common ground that would be suitable for all interested parties. Developers behind SER and Kamailio showed interest, developers behind OpenSIPS decided to go their own way.
Thus, the SIP Router project was born. The goal of the project is to unite developers from SER and Kamailio projects and see if we can establish a common ground and join our development efforts, eventually getting to a common server based on a common code base.
A meeting was held on November 4, 2008, in Karlsruhe, Germany, to sketch the integration plan, shortly: each project will complete the development cycle at that time and do one release based on old source code, then complete the integration and do next release using SIP Router source tree.
Lineage of SER Related Projects
Kamailio (OpenSER) 1.5.0
On March 02, Kamailio (OpenSER) 1.5.0 is released, the last major version of this project which is not based on SIP Router Project, most of development efforts being directed from then on to integration process.
SIP Express Router (SER) has not explicitly packaged a new release before migrating to SIP Router Project source code tree, staying in former CSV repository as version 2.1.0.
Branching for 3.0.0 version
On October 10, two branches were created in GIT repository: sr_3.0 and kamailio_3.0. It is the milestone marking the end of integration phase of Kamailio (OpenSER) and SIP Express Router (SER) and beginning of testing period prior new major version release.
Kamailio (OpenSER) 3.0.0
On January 11, Kamailio (OpenSER) 3.0.0 was released, first version completely based on SIP Router Project.
SIP Express Router (SER) has not yet packaged a new version, the GIT branch sr_3.0 is the way to fetch it for now.