This feature also configures the fabric between ingress and egress ports to optimize PFC behavior.
When the ingress and egress ports are located on separate nodes in a SummitStack, note that some older systems do not support the enhanced fabric mode required for PFC.
If any other ExtremeSwitching switch attempts to join the stack after the initial configuration of PFC, it is not allowed to join.
If your situation does not respond well to having flow control enabled on the fabric links, you can turn off flow control in the fabric by using the following command:
configure forwarding flow-control fabric [auto | off]