ESXi can use Fibre Channel over Ethernet (FCoE) adapters to access Fibre Channel storage.
The FCoE protocol encapsulates Fibre Channel frames into Ethernet frames. As a result, your host does not need special Fibre Channel links to connect to Fibre Channel storage, but can use 10 Gbit lossless Ethernet to deliver Fibre Channel traffic.
To use FCoE, you need to install FCoE adapters. The adapters that VMware supports generally fall into two categories, hardware FCoE adapters and software FCoE adapters.