Find what is on a subnet
In the product todaySweeps the ranges you give it by opening ordinary TCP connections, so it needs no special privileges on the host. A device that refuses a connection is recorded as present, not missed, and the ports it tries include the ones network equipment really answers on, not only the obvious two.
Work out what each device is
In the product todayMatches hardware addresses against a vendor database, reads identifying values over SNMP where a device offers them, and resolves a model from what it finds. It declines to guess when the answer is ambiguous.
Read the links between devices
In the product todayAsks switches and routers what they can see next to them, and builds the adjacency from their own neighbour tables, not from a drawing somebody maintained by hand.
Keep a history worth reading
In the product todayTurns interface counters into rates, and knows the difference between a counter that reset because the device rebooted and traffic that genuinely went backwards. It will not draw a smooth line through a gap in collection it knows nothing about.
Tell a degraded link from a dead one
In the product todayWatches upstream links and distinguishes the case everybody misses: the gateway answers, the internet does not. Where traffic is still moving it trusts the traffic over the ping.
Report availability honestly
In the product todayWeights each measurement by the time until the next one, not by counting samples, and does not charge its own collection gaps to your provider.
Receive device logs locally
In the product todayAccepts log messages in both standard formats, including the awkward parts: a December timestamp arriving in January, and the byte order mark the specification permits. The listener stays off until you turn it on, so an upgrade never opens a port you did not ask for.