多项选择题
A. SONET and SDH both use time-division multiplexing.
B. An optical transport network system uses time-division multiplexing.
C. SONET and SDH both use wavelength-division multiplexing.
D. An optical transport network system uses wavelength-division multiplexing.
多项选择题 Which two statements are true about TCP communication?（）
多项选择题 A user opens a webpage that requires the transmission of packets from the Web server to the clients browser. The packets transmitted from the Web server to the client exceed the smallest MTU value on the communications path. Which two protocol functions allow this type of communication?（）
单项选择题 Why is IPv6 packet processing more effective than IPv4 packet processing?（）