Explanation/Reference:
Section: Considerations for Expanding an Existing Network Explanation
Explanation
Virtual PortChannel (vPC) can be used to create redundancy and manage loops between multiple devices.
PortChannel is used to bundle multiple physical links into a single logical link between two network devices. A logical link that is built from multiple physical device links creates redundancy between the two devices, which ensures that network traffic can continue to flow in the event of a failure on one of the physical links. However, a single PortChannel can be configured between two devices only. vPC expands upon the capabilities provided by PortChannel by enabling the creation of a logical link between more than two devices, which further increases redundancy by providing additional pathway possibilities.
Virtual routing and forwarding (VRF) is a network virtualization mechanism that is used to maintain multiple independent routing tables on a single router. When VRF is used, the same IP addressing scheme can be applied to different routing tables on the same router. As the fundamental basis of a virtual network, VRF can be used to build numerous virtual private networks (VPNs), which all use the same infrastructure and the same addressing scheme without each instance interfering with each other.
A Virtual Device Context (VDC) is a device virtualization mechanism that enables an administrator to divide a single physical switch into up to four virtual switches. Each virtual switch, which is also referred to as a VDC, has its own control and data plane instances, configuration files, physical ports, and memory-related processes. For example, the active spanning tree configuration on one virtual switch would run in a completely separate memory space as the spanning tree configuration on another virtual switch, even though both virtual switches share the same physical memory.
A virtual LAN (VLAN) is a network virtualization mechanism that enables multiple LANs to pass traffic on a single physical interface. VLANs are configured on network switches to create two or more separate LANs on the same switch. VLANs are used to simplify network administration and to reduce the size of broadcast domains. Hosts on one VLAN cannot communicate with hosts on other VLANs unless a router or an Open Systems
Interconnection (OSI) Layer 3 switch is used to provide inter-VLAN routing.
Reference:
CCDA 200-310 Official Cert Guide, Chapter 4, vPC, p. 154
Cisco: Virtual PortChannel Quick Configuration Guide