iLocus has done some great market research. In a recent report they highlighted the Top 10 Vendors that Established VoIP. It's an interesting. read. Nice to see my own view of the important role of Sonus in their report. They note Sonus Networks’ strong presence in the telecommunications market, accrediting Sonus as playing “a bigger role in transformation of public networks than any other equipment vendor”.

The 10 that Established VoIP (Part 4: Sonus Networks)
By JR
By 1999, the first phase of VoIP miracle had been achieved. People could make international calls for a fraction of the cost they previously paid. Companies like Vocaltec and ITXC had made significant contributions in making that happen. The next big thing in VoIP was pushing packetization to the trunk level. But the vision varied in the industry.

Service providers at the time had two choices: either continue using public Internet to transport national long distance voice traffic, or somehow re-engineer their own networks to become compatible with the data-voice convergence trend. The first option was simply not good enough because there was not enough IP bandwidth to transport high volumes of voice traffic. VoIP technology also was not mature and scalable enough to handle high volume voice traffic. Service providers therefore began a long march toward a re-engineered PSTN.

And there were several players around who bet on this move. Among them were Transmedia, IP Cell, IP Verse, Oresis, Santera, Telica, Convergent Networks, Sonus Networks, Rapid 5 Networks, EmpowerTel, Salix, Cisco etc. The legacy vendors also offered enhancements to their existing TDM switches.