A. 802.1P priority is identified by the prionity field in the VLAN tag

B. The TOS field of the current IP packet contains two fields: IP priority and service type, of which IP priority occupies 3 bits.

C. DSCP defines four types of network processes, among which the accelerated forwarding EF class is divided into four subclasses EF1/2/3/4

D. 802.1P priority is divided into 4 levels from 0 to 3