In the good old days, it was pretty easy to figure out who was who in most IT departments. You had some folks who did servers, some who ran the network, some who focused on storage, and generally a much larger group dedicated to applications and development.
This siloed arrangement has functioned pretty well. Employees assigned to their respective pieces of the IT infrastructure puzzle were as skilled and experienced in their responsibility as possible. If a new piece of storage or server tech came out, the network guy didn't need to know much about it, just as long as he was aware of how many and what kind of ports the server folks were going to request.
The downside of such compartmentalization is that it tends to breed inefficiencies and the occasional battle of wills. I have worked in environments where a server admin tasked with rolling out a new machine had to file a work order and wait two days to get a pair of network ports configured -- only to file a separate work order to provision a few SAN volumes.
For better or worse, the era of the silo is coming to an end. Convergence is upon us, thanks to the proliferation of server virtualization and the rise of IP storage. Many servers now ship standard with built-in 10GbE CNAs (converged network adapters). Sticking with the old server, storage, and network model simply doesn't fit anymore.