TSE (if you refer to the ip module in sopc builder) is a MAC.
TSE MAC = Triple Speed Ethernet Media Access Controller
This is the device which converts your data in a format which can be transmitted on your actual network.
PHY is the physical layer device, namely the transceiver which connects to the wire, optical fiber, RF or whatever you have.
The MAC is a digital devices, so it can easily be integrated in FPGAs, while PHY is usually an external device.
Cris
