M country N project , one commecial site NodeB service down. The topology is like attachment. The service is PWE3 service which carried by MPLS tunnel. The NE version is V1R3C00.
Modify NE(7-86) port layer 2 attribute from hybrid back to tag-aware, the service recover.
Use LSP ping from NE(7-83) to NE(7-89),it fail. Use LSP traceroute , it can reach NE(7-86).So the tunnel from NE(7-86) to NE(7-87) is down.
Check tunnel parameter, do not been modified.
Check the NE ARP list, it is found NE do not learn MAC of peer NE port. It doubt the port layer 2 attribute was modified. Because for RTN V1R3 version, the port default layer 2 attribute is tag-aware, if one NE port layer 2 attribute is modified to hybrid, it send and reply ARP frame without VLAN, so that when the peer NE port whose layer 2 attribute is tag-aware receive the ARP frame without VLAN will drop the frame.
Check two NE port layer 2 attribute, NE(7-86) is modified to hybrid.