Use ARP data to detect neighbor

[Vidar Faltinsen]

Today the algorithm for deciding a L2 neighbor is in this order:

1) LLDP data
2) CDP data
3) CAM (bridge table) data

I suggest a forth level:

4) ARP data

There are circumstances for L3 link networks, i.e. two routers linked back to back, that neighbors are not discovered by NAV.
Typically LLDP and CDP are not supported/enabled in these scenarios. If the ARP data reveal only one other neighbor, this should be a candidate for neighbors

An implementation that supports this will give added value to the IP device info neighbors tab, and the link down alarm.