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
Offer direct white route to Viet Nam termination with competitive rate
and high quality. 100% full CLI and Non CLI; ASR: 65%;
ACD: 13 minutes; PPD: 30s and Capicity 5000 calls.