Fibre Channel does not follow the layering, and is split into five layers: • FC-4 – Protocol-mapping layer, in which upper-level protocols such as (NVMe),, IP, and are encapsulated into Information Units (IUs) for delivery to FC-2. Current FC-4s include FCP-4, FC-SB-5, and.• FC-3 – Common services layer, a thin layer that could eventually implement functions like or.