The virtual port channel (vPC) technology that is used by the Cisco Nexus 5000 and 7000 Series switches enables Multichassis EtherChannels (MECs) to be formed between a network device and two separate physical chassis.
vPC technology allows logical loop-free Layer 2 topologies to be created, which prevents Spanning Tree Protocol (STP) from blocking any of the ports in the network topology
This Picture shows every types of vPC that implements commonly.
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