IPv4 and IPv6 over GRE tunnels using IPv4 transport

This feature enables IPv4 and IPv6 traffic to be transported through GRE tunnels over an IPv4 network. It supports both encapsulation and de-encapsulation of IPv4 and IPv6 payload packets. During encapsulation, the device adds GRE and outer IPv4 headers so the traffic can traverse an IPv4 transport network. During de-encapsulation, the device removes the outer IPv4 and GRE headers and forwards the original IPv4 or IPv6 payload toward its destination.