Point-to-point GRE tunnel with FVRF (tunnel vrf command)

Point-to-point GRE Tunnel without FVRF

What Is FVRF(Front door VRF)?

BGP neighbor as-override command

BGP neighbor allowas-in command

BGP Route RIB Failure

Why the OSPF neighbor state gets stuck in Exstart?

OSPF LSAck(Link State Acknowledgement) Packet

OSPF LSU(Link State Update) Packet

OSPF LSR(Link State Request) Packet