Ethernet 0 and ethernet 1 ports

Hi, 

We just received Dell Equallogic 4210X SAN with Type 19 controllers. They have both ethernet and fibre optic connectors, but I am surprised that there are two of each, labeled ethernet0 and ethernet1. 

Will the SAN function properly with just Ethernet 0 connected from each controller? Or do I need both Ethernet 0 and 1 connected? 

Thanks, 

Jakub