Topology: device of C enterprise---AR46-40
Device of C enterprise and AR46-40 build EBGP neighbor relation. The device of C enterprise acts as PE and AR46-40 CE. These two devices are MB full-duplex and they are connected through the cable and enable their sub-interface.
The physical and protocol state of the physical interface are up; for sub-interface, the physical state is up but the protocol state is down. They cannot communicate and the service cannot be established.
1. Check physical link and change the cable. The link is not problematic.
2. Connect AR46-40 with laptop and it is still problematic. The interfaces of two devices are forced MB full-duplex and the problem is not solved.
3. Configure vlan-type dot1q vid 100 under sub-interface.
The command under sub-interface is to terminate vlan and opposite router device cannot recognize the data with VLAN. In the topology there is no application of VLAN. The software is of bug.
1. The physical link is problematic.
2. The interconnection of different enterprises and negotiation are problematic.
3. The configuration is problematic.