Use Case 4: Adding a switch to a stack

The automatic configuration mode only works with a newly unboxed switch, or a switch which has been reset to factory default configuration using the CLI command erase startup-configuration. Now, connecting the switch in between the two end switches of the chain will trigger an automatic configuration download to the switch, after which it will join the stack.

In manual configuration mode, the switch to be added has to be configured to join the stack. This involves the following steps:

Prerequisites
A functional running stack can be scaled up by adding a switch to increase capacity. There will be minimal disruption of switching function during this operation. This process is similar to the VSF deployment, and can be done in either Manual or Automatic configuration mode.
NOTE:

The maximum number of members in a VSF stack is 8.

  • The first step is to convert running stack to chain, if it is in ring topology. To increase the stack size, add a new switch to the stack, and then convert it back to a ring.

  • This involves disconnecting a VSF link between two stack members. Switching functions will continue, with possible loss of some in-flight traffic.

Procedure
  1. Configure new switch links, which will be connected to the two end switches of the chain.
  2. Enable VSF on new switch with the same Domain ID as the stack. This will cause the switch to reboot.
  3. Connect the cables to the end switches of the stack, and the stack will be formed.

    There could again be some possible loss of some in-flight traffic as a ring topology forms from the chain topology.