The Canonical Format Indicator (CFI) in the VLAN tag, also called Drop Eligible Indicator (DEI), identifies the drop priority of packets in certain situations. When the rate of packets on certain devices exceeds the committed information rate (CIR) value, the value of the DEI field is set to 1. In this case, the drop priority of the packets is high. When congestion occurs, the devices first discard the packets whose DEI field is 1.
If packets whose rate exceeds the CIR need to be discarded, configure CFI as the internal drop priority.