No problem here, but I got curious after noticing an unexpected IP address in cdp neighborhood output.
We use Vlan999 for management vlan. Usually I see a Vlan999 ip address in cdp neighbors. Today, instead, I see a Vlan2 ip address for one of our 4506's. (cdp neighbor command executed on a 3550. connection between 3550 and 4506 is trunk.)
I look around some more, discover that most switches only have Vlan999 configured. The unusual switch has many vlans configured, starting with Vlan2 (Vlan1 is shutdown).
(And that makes sense. We have 5 sites. This 4506, with native IOS, is site core at a small site - all other site cores are 6509 with CatOS/IOS.)
So, it appears to me that CDP sees the IP address of the lowest interface it finds at the other end of a trunk.
Is that correct?