Which version of NTP was the first to support cryptographic authentication?（）

A. By calculating the time offset from the GPS or atomic clock
B. By setting the router clock to the default value if the router can't connect to a time server
C. By setting all network devices to the correct time
D. By setting necessary time date in the timestamp information

A. The class-map "all-traffic" will match all traffic with ip precedence 4 and 5
B. The class-map "all-traffic" will match all traffic with dscp 18 or dscp 43
C. The class-map "all-traffic" will match all traffic with ip precedence 0 or 1
D. The class-map "all-traffic" will match all traffic with dscp 18 and dscp 43