Loopback based IPv4 / IPv6 over IPv4 Encapsulation

Network Time Protocol (NTP) supports IPv4 and IPv6 VPN routing and forwarding (VRF) requests. This support enables an NTP server running on a provider edge (PE) router to respond to NTP requests from a customer edge (CE) router. As a result, a PE router can process any NTP request packet coming from different routing instances based on either IPv4 or IPv6 loopback addresses.