When VP8620 disconnect with MMPU board, 2 MMPU slots on local management branch graph is grey. (Active/standby board does not switch over when active MMPU disconnect).
1. Remove active MMPU, switch over to standby MMPU board, it is normal. Insert the master MMPU board back into slot and switch over to master MMPU. Fault emerges after about 10 hours. Maybe it is caused by main MMPU board. Move the normal standby MMPUT to main slot and fault emerges after about 10 hours. So eliminate board failure.
2. Cannot connect MMPU address through PING command after disconnection, it may be network failure. Check network, plug network cable of VP8620MMPU from switch and connect to portable computer. It cannot connect through PING command. Replace the cable with a standard cable, the connection is normal. And the problem is solved.
1. Board failure, VP8620 board software not delivery-attached.
2. Network failure.
It is hard to find that it is caused by network cable, and spend a lot of time to location on device side. Please be careful in daily maintenance.