Implementing vPCs – Cisco CCNP and CCIE

There are many considerations that you need to be aware of when you are implementing vPCs:

  • You must configure the peer-keepalive link and adjacency between peers must be formed before the system can establish the vPC Peer-Link.
  • A vPC peer link must consist of Ethernet ports with an interface speed of 10 Gbps or higher. It is recommended that you use at least two 10-Gigabit Ethernet ports in dedicated mode on two different I/O modules.
  • vPC peers must run the same Cisco NX-OS release. During a software upgrade, you must upgrade the primary vPC peer first.
  • You must pair Cisco Nexus switches of the same type.
  • When forming a vPC domain between two Cisco Nexus 9300 Series switches, both switches must be the exact same model to form a supported vPC domain. When forming a vPC domain between two Cisco Nexus 9500 Series switches, both switches must consist of the same models of line cards, fabric modules, supervisor modules, and system controllers inserted in the same slots of the chassis to form a supported vPC domain.
    A vPC keepalive should not run across a vPC peer link.
    A vPC domain, by definition, consists of a pair of switches that are identified by a shared vPC domain ID. It is not possible to add more than two switches to a vPC domain.
    A vPC is a Layer 2 port channel. A vPC does not support the configuration of Layer 3 port channels. Dynamic routing from the vPC peers to the routers that are connected on a vPC is not supported. It is recommended that you establish routing adjacencies on separate routed links.
    You can use a vPC as a Layer 2 link to establish a routing adjacency between two external routers. The routing restrictions for vPCs apply only to routing adjacencies between the vPC peer switches and routers that are connected on a vPC.
    Tables 2-14 through 2-17 show the most-used port channel and vPC configuration commands. For a full list of commands, refer to the Nexus interface and virtual port channel configuration guide links in the “References” section at the end of this chapter.