reliably detecting the presence of a bridge?

I am curious if there is some sort of igmp or other form of message that would reliably detect if a switch had a bridge on it. How could deviceA detect deviceC was a bridge in this case? deviceA -> ethernet switch -> deviceB ethernet switch -> deviceC with bridged wifi and ethernet question came up in the context of: http://lists.alioth.debian.org/pipermail/babel-users/2015-December/002231.ht... -- Dave Täht Let's go make home routers and wifi faster! With better software! https://www.gofundme.com/savewifi