First, I make sure that the network is the bottleneck. Once I'm sure that it is, I complain to the network people. They take it from there.

Sometimes I have to work with them. And I do need to be sure that the host is talking correctly to its link partner. If a network card is in half-duplex mode, while the port is in full-duplex mode then network performance will suffer severely and at least half of that problem is mine.

But you need to understand that the network is not my responsibility. I am part of a team that administers some things that connect to it.