单项选择题
A. Cisco Proprietary payload compression B. Predictor payload compression C. RTP header compression D. TCP header compression
A.Version 1 B.Version 5 C.Version 4 D.Version 3
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