Algorithm for mapping network devices

Question

Does anyone know a good method for mapping devices on a network?

I am looking for something that can establish the connection layout between devices to build a visual network diagram.

Any ideas?

Answer 1

This isn't an algorithm, but rather a protocol (or protocols) for discovering neighbors. If your switches/devices have Link Layer Discovery Protocol (LLDP) enabled, you can use that to determine a network of physical connections.

Note that older Cisco switches might not have LLDP, but will have CDP, a proprietary implementation of discovery. Same goes for Nortel and Extreme switches which also have their proprietary protocols. But LLDP is now the standard (802.1AB) that should be used for discovery.

You can also see on the Wikipedia page that there are implementations of LLDP (and other proprietary protocols) for Linux/Windows/Mac. Also, VMware ESX implements CDP.