SourceForge Logo Linux CISCO Discovery Protocol

Welcome to the Linux CDP home page.

The CISCO Discovery Protocol is implemented as a module for the Linux kernel. At this stage only 2.4.x (where x >= 15) kernels are supported. Sources are distributed as a patch against the linux kernel. In general, it is tested against the latest available kernel.

The data becomes available through the /proc interface as /proc/net/cdp_neighbors. The format is very similar to the CISCO equivalent enable command "show cdp neighbors detail". Of course this means that the proc filesystem has to be enabled for it to work (which is usually the case for most distributions).

Details of the CDP protocol have been collated from several sources:

Please note that when documentation obtained differed from actual output obtained from a CISCO device, the device's output was assumed to be authoritative.