AT&T is offering users another flavor of VPN that the carrier says is more economical than traditional frame relay networks and typically more economical than customer premises equipment-based IP VPNs.AT&T\u00a0is offering users another flavor of VPN that the carrier says is more economical than traditional frame relay networks and typically more economical than customer premises equipment-based IP VPNs.AT&T's Network Based IP VPN service runs over the Multi-protocol Label Switching (MPLS) public IP network, which lets users set up a fully meshed IP VPN. This is in addition to AT&T's current network-based VPN service, IP Enabled Frame Relay.AT&T is not the first carrier to offer a network-based IP VPN service, but it says most competitors, such as Sprint and MCI, are doing so over private IP networks. AT&T is using MPLS to keep its customers' VPN traffic separate and secure as it runs over the carrier's Internet backbone."Native IP provides cost advantages to customers because they can opt for usage-based billing . . . and multiple management options," says Rose Klimovich, vice president and general manager of global VPN services at AT&T. Also, because the service is supported on the carrier's "native IP infrastructure," IP VPN customers are using the same access routers as dedicated Internet access customers. This presents a cost advantage to AT&T, which doesn't need to manage multiple edge devices to support multiple services.In contrast, AT&T's IP Enabled Frame Relay service uses different edge gear to connect users coming into the Internet network via dedicated frame relay circuits.One customer is seeing the cost benefits. CS Group, which provides building products for architects, moved from a national frame relay network to the AT&T Network Based IP VPN service about six months ago and expects to save $100,000 over the next two years, says Michael Dyson, director of IT at the Lebanon, N.J., company."The main reason we went with an MPLS network is because we have a fully meshed network for less per month," Dyson says. "Every site has a dedicated T-1. Before we had all of these [permanent virtual circuits] with bandwidth restraints and single points of failure."CS Group also moved away from frame relay because it wanted to deploy advanced applications such as VoIP and unified messaging. Dyson says his group is in the midst of deploying both.Currently AT&T is only offering its Network Based IP VPN service domestically. The carrier says it will roll out the service internationally in the future, but would not provide a time frame.AT&T's offering includes a standard service-level agreement. The carrier guarantees 99.99% service availability, that latency will not exceed 60 millisec and that packet loss will not exceed 0.7%.The service starts at about $700 per month per dedicated T-1 site, depending on number of sites. Users can have AT&T fully manage their network or choose the unmanaged version of the service. AT&T also offers burstable T-1 services where fees are based on average usage for the month.