Design, implementation and support of VoIP services. From small PBX's to big centrex systems. Integration with existing and new environment. About 10 years of hands-on experience in the area. Deep knowledge of the related standards as well as the best practices. Hands-on experience with open and commercially licensed products including Asterisk, Opensips, Kamailio, Broadsoft BroadWorks, Vocaltec Essentra.