Disabling Split Detection in a Virtual Chassis Configuration

If there is a disruption to a Virtual Chassis due to failure of a member device or one or more Virtual Chassis port links, the resulting connectivity loss can cause a split in the Virtual Chassis configuration. Split detection, which is enabled by default in an MX Series and EX9200 Virtual Chassis, identifies the split and minimizes further network disruption.

You can disable split detection by including the no-split-detection statement at the [edit virtual-chassis] hierarchy level. Disabling split detection can be useful in certain Virtual Chassis configurations.

For example, if the backup device fails in a two-member Virtual Chassis configuration and split detection is enabled (the default behavior), the primary device takes a line-card role, and the line cards (FPCs) that do not host Virtual Chassis ports go offline. This state effectively isolates the primary router or switch and removes it from the Virtual Chassis until connectivity is restored. As a result, routing or switching is halted and the Virtual Chassis configuration is disabled. By contrast, if the backup router or switch fails in a two-member Virtual Chassis configuration and split detection is disabled, the primary router or switch retains primary role and maintains all of the Virtual Chassis ports, effectively resulting in a single-member Virtual Chassis consisting of only the primary device.