VPN
VPN
Many definitions exist for Virtual Private Networks (VPNs). VPNs refer to encrypted tunnels that carry packetized data between remote sites. VPNs can use private lines, or use the Internet through one or more Internet Service Providers (ISPs). VPNs are implemented in both dedicated hardware and software, but can also be integrated as an application to existing hardware and software packages. A common example of an integrated package is a firewall product that can provide a barrier against unauthorized intrusion, as well as perform the security features that are needed for a VPN session.
The encryption process can take from less than 1 millisecond (ms) to 1 second or more, at each end. Obviously, VPNs can represent a significant source of delay, and therefore have a negative affect on voice performance. Avaya VPN products encrypt traffic with less than 1ms of delay, and thus are appropriate for IP Telephony. Also, because most VPN traffic runs over the Internet and there is little control over QoS parameters for traffic crossing the Internet, voice quality may suffer due to excessive packet loss, delay, and jitter. Users might be able to negotiate a
Convergence advantages
For increasing numbers of enterprises, the VPN carries not only data, but voice communications. Though voice communication over IP networks (IP Telephony) creates new quality of service (QoS) and other challenges for network managers, there are compelling reasons for moving forward with convergence over maintaining a traditional voice and data infrastructure:
●A converged infrastructure makes it easier to deploy eBusiness applications, such as customer care applications, that integrate voice, data, and video.
●Enterprises can reduce network costs by combining disparate network infrastructures, and eliminating duplicate facilities.
●A converged infrastructure can increase the efficiencies of the IT organization.
●Long distance charges can be reduced by sending voice over IP networks.
Voice over IP VPN is emerging as a viable way to achieve these advantages. The emergence of public and virtual private IP services promises to make it easier for customers, suppliers, and businesses to use data networks to carry voice services. As with any powerful new technology, however, VPNs require skilled management to achieve top performance. The highest network performance becomes imperative when the VPN network must deliver
