Thank you for your reply.
Now, my problem is that VCG cannot forward edge traffic. When edge sends packets through the tunnel established by VCG and the packets are sent to VCG, the VCG directly forwards the packets to the directly connected router (the packets are original packets without tunnel encapsulation), so the router does not know how to reach the private IP address of edge. The router discards the packet. Please refer to my topology and router packet forwarding result. When I built my own tunnel from edge to edge, communication was normal. When I built my own tunnel from edge to edge, communication was normal.