I am wondering if there are any Linux tools out there which might aid in identification of hosts directly connected to each other (much like Cisco Discovery Protocol on switches)?
I have found http://sourceforge.net/projects/lcdpd/ which searching. But it appears to be a dead project and the patch is only for older kernels.
I am just trying to alleviate the tedious task of ethernet interface to ARP MAC address to hostname lookup. A bonus would be something that also announced its own neighbors so you could have a 2 hop view of the rest of network.
Are you looking for LLDP?
Agent software is out there for Linux, and many network devices support it.