Symptom
ACI mode switches do not support link level flow control until 14.2.6 version, but only support priority flow control (PFC). Upon receiving the pause frame which is for link level control, there will be a chance to back-pressure the forwarding plane such as CPU oriented traffic are being dropped. Hence when PFC is enabled for a port, t is important to make sure the pause frame are priority flow control type instead of standard link level flow control type.
Conditions
ACI port had PFC enabled but peer port is only capable for link level flow control pause frame.
Workaround
disable LLFC for the peer port if it does not support PFC but only link level flow control.
