What is a feature that enables VPN connections to successfully maintain a private and secure...

Wire Mode is a VPN-1 NGX feature that enables VPN connections to successfully fail over, bypassing Security Gateway enforcement. This improves performance and reduces downtime. Based on a trusted source and destination, Wire Mode uses internal interfaces and VPN Communities to maintain a private and secure VPN session, without employing Stateful Inspection. Since Stateful Inspection no longer takes place, dynamic-routing protocols that do not survive state verification in non-Wire Mode configurations can now be deployed. The VPN connection is no different from any other connections along a dedicated wire, thus the meaning of "Wire Mode".

References: VPN Administration Guide