using VOIP accross an SSL-based VPN can actually improve the call quality (as measured by MOS scores). The improvement seems to be due to encapsulating the UDP VOIP packets ( SIP and RTP ) in TCP/IP. NB Datagram-based VPNs, such as IPSec's ESP are still bad.

Service Providers serving enterprises need a VoIP VPN solution that offers rapid low cost expansion to new regions/cities to exploit new opportunities; enable creation & deployment of a wide range of differentiated services that can be easily customized by enterprise end-users in addition to seamless interworking between different TDM signaling standards and IP protocols and high level of flexibility in routing & service policies to adapt to changing customer requirements.

With Next voip tech's VoIP VPN solution, enterprises can establish company-wide high quality VoIP communications system and significantly reducing their operating expenses.

VPN for VOIP connection service:
Bandwidth: Dedicated 256 kbit/s up stream and 256 kbit/s down stream with QoS guaranteed for VOIP applications, allows about 20 simultaneous calls with G.723.1 codec, 60ms RTP size and VAD enabled, or about 600,000 minutes per month
Monthly service fee: US$49.95

Key Benefits:

• Enables Service Providers to add value to their multi-site enterprise customers regardless of the voice services systems utilized at various sites


• Enables Service Providers to cost effectively expand services to branch offices of their multi-site global enterprise customer-base in any geographic market by reducing the costs of leased lines when sourced from a third-party provider


• Enables Service Providers to provide enhanced management for multi-site enterprise customers with centralized network management of highly sophisticated & easily customizable VPN policies


• Service Providers enable their enterprise customers to
  leveraging existing Customer Premise Equipment (CPE)
  investments


• Enables Service Providers to seamlessly connect between
  distributed enterprise locations with different types of
  access network topologies and CPE, without the need
  for expensive point-to-point connections.


• Service Operators can leverage Next comm tech's Service Broker
  solution to combine VPN services with a wide range of other
  enhanced services for further revenue generation.