A. Offloads the STP requirement from the external Access layer switches
B. If upstream access switches do not support vPC or VSS the dual-homed ESX host traffic canstill be distributed using virtual port channel host mode using subgroups automatically discoveredthrough CDP
C. Allow transit traffic to be forwarded through the ESX host between VMNICs
D. Can be divided into multiple virtual device contexts for service integration， enhanced security，administrative boundaries， and flexibility of deployment