VIVA offers IP based Converged Communications Solutions. You may contact VIVA for SIP Trunking, IP PBX & PSTN integration, MS OCS & IP PBX integration, Managed VoIP and ''''Secure'''' VoIP.
Concerning practical implementation, the VoIP gateways have proven to be the best. Many companies are successfully using the IP telephony thanks to its two main characteristics
Decrease in international and long distance call cost expenditures
Stable communications between company’s offices throughout different cities and counties