A. Two peer devices： the vPC peers of which one is primary and one is secondary and are part of a vPC domain.
B. A Layer 3 Gigabit Ethernet link called peer-keepalive link to resolve dual-active scenarios
C. A redundant 10 Gigabit Ethernet PortChannel called a peer link to carry traffic from one system to the other when needed
D. vPC member ports forming the PortChannel
E. A dot1q trunk between the vPC peers
F. A management port that can be used as peer-keepalive link to resolve dual-active scenarios.