When configuring a vHBA template in UCS Manager, you need to specify the WWPN (World Wide Port Name) from a WWPN pool (B) to uniquely identify the port in the fabric, and the Fabric ID (E) to define the path through which the SAN traffic will flow. https://www.cisco.com/c/en/us/products/collateral/servers-unified-computing/ucs-manager/whitepaper_c11-6973