Before upgrade the version is VRP3.10-0426sp03 and after upgrade the version is VRP3.10-232112 and IP-Trunk cannot be up.
The physical state of the interface is up, but the protocol state is down.
1. Check physical interface and it is up. .
2. Check IP-TRUNK interface information and it is found that the link layer protocol of the interface in new version is HDLC, but IP-TRUNK interface of opposite device is PPP protocol.
3. In new version IP-TRUNK interface only supports HDLC protocol. Change opposite device as HDLC and the problem is solved.
1. The physical link is problematic and the interconnection of the packet on protocol layer fails.
2. The protocol of two ports is different and the negotiation cannot succeed.