What to use to auto-discover devices on the network?

Question

Monitoring

Hello!
Can you tell me a utility or system for automatically scanning the network and building a primitive map?
There is a multi-level network, with a bunch of vlans, many devices are duplicated for fault tolerance. I would like to find a program in which you enter a list of device addresses, it scans them, detects downstream devices and displays them in a readable form (ideally, it builds a diagram).
PS devices more than a thousand
PPS Zabbix cannot

Answer 1

Just like that with a card, all paid. But keep in mind that discovery protocols (cdp, lldp, naturally snmp) must be configured on the equipment. For example, I used SNMPc