What does the 'IP protocol field' (or IPv6 'Next Header' field) contain, and give three example values?

• A.The protocol field contains the DSCP value for QoS marking of the packet
• B.The IPv4 Protocol field (8 bits) identifies the Layer 4 (or encapsulated) protocol in the payload; it allows the receiving IP stack to demultiplex the payload to the correct handler. Values: 1 = ICMP; 6 = TCP; 17 = UDP; 47 = GRE (Generic Routing Encapsulation); 50 = ESP (IPsec Encapsulating Security Payload); 51 = AH (IPsec Authentication Header); 89 = OSPF; 132 = SCTP
• C.The protocol field contains the TCP or UDP port number of the encapsulated segment
• D.The protocol field contains the IP version number (4 or 6) for dual-stack routing