IEEE 802.1Q (RSTP) must be enabled. All external switches must be configured to allow the cDAQ chassis to transmit RSTP packets, known as Bridge Protocol Data Units (BPDU). If any switch has a feature—such as “BPDU guard”—enabled, the port connected to the cDAQ chassis is disabled and communication is lost. Refer to the documentation for your external switch for information about enabling RSTP and disabling BPDU guards on the switch.