When the L1, L2 network between the two Fabric Interconnects is disconnected or fails, the primary FI continues to serve as the primary; however, the secondary FI concludes that the primary FI is dead and tries to become the primary. This is split brain partition in space because each Fabric Interconnect considers itself to be in control of the cluster.

When a partition in space is detected, both FIs immediately demote themselves, start the election process, and start claiming chassis resources (known as quorum). The FI that claims more resources wins the election and stays in the cluster whereas the other FI aborts. When the link is restored, the second node can rejoin the cluster as a subordinate.