I think maybe they meant linking Port 1 to Port 2, and Port 3 to Port 4? Also I believe gigabit ethernet can be full duplex, so you should be able to send 1000

I think maybe they meant linking Port 1 to Port 2, and Port 3 to Port 4? Also I believe gigabit ethernet can be full duplex, so you should be able to send 1000 and receive 1000 on a single interface at the same time if it's in full duplex mode.