Traffic prioritization ieee 8021p traffic prioritization ieee 8021p allows real time traffic classification into eight priority levels mapped to eight queues layer 4 prioritization layer 4 prioritization enables prioritization based on tcpudp port numbers class of service cos class of service cos sets the ieee 8021p priority tag based on ip address ip type of service tos layer 3 protocol tcpudp port number source port and diffserv rate limiting rate limiting sets per port in