The CDP and LLDP protocols make it possible to discover connected devices on managed switches, without having to rely on port descriptions. This functionality is quite useful when dealing with large numbers of rackmounted servers with varying network configurations (PXE).
After looking at the available unix CDP/LLDP daemons I’ve decided to write my own CDP / LLDP sender. It’s a small daemon which sends out link-layer advertisements on a list of interfaces, after dropping privileges. The code should work on Linux and FreeBSD. Future enchancements will include sending more network (IPv6 addresses, duplex, mtu) and system (LLDP-MED / DMI) information, due to the OS specific nature of these details support for these options will be platform dependent.
Download ladvd.