I've read about data center network architectures - Fat-tree, Clos (or spine-leaf), DCell, BCube... None of these make any specific mention of the management network, which I expect would be out-of-band in a data center. Am I right in expecting it to be out-of-band? And if so, are server management interfaces connected to this management network as well? What is the architecture of this network? For a large data center, it needs to be scalable.
I'm interested in what current practice is, as well as what's the right way to do it (in case they're not the same).