Switch high availability options

There are various ways that switches can be physically and logically combined to deliver redundancy as well as scalability in a network. These are briefly described below:

  • Virtual Switching System (VSS)
    • Allows two Cisco Catalyst devices (6500 and 4500 series) to bond together so that they are seen as a single virtual switch to the rest of the network.
    • Connect by creating virtual switch links over regular Ethernet connections.
    • They combine into a single control plane.
    • Older technology, replaced by StackWise Virtual, described below.
  • StackWise
    • Allows two or more switches to act as a single switch
    • Connect using specialized StackWise cabling that extend the backplane of the switches
    • Combine into a single control plane
  • StackWise Virtual
    • Allows two switches to act as a single switch
    • Connect using 10G or 40G ethernet links
    • Combine into a single control plane
    • Supported on 9000 series switches
  • vPC
    • Supported on Nexus switches only
    • Allows two switches to operate in an active/active arrangement
    • Maintain two control planes, but are synchronized