单项选择题
Which IPv6 address is valid?（）
A. 2031:0:130F::9C0:876A:130B B. 2001:0DB8:0000:130F:0000:0000:08GC:140B C. 2001:0DB8:0:130H::87C:140B D. 2031::130F::9C0:876A:130B
单项选择题 Which of the following protocols uses both TCP and UDP ports?（）
单项选择题 Which command enhances the 802.1D convergence time on ports that are connected to hosts?（）
单项选择题 Which IEEE standard protocol is initiated as a result of successful DTP completion in a switch over FastEthernet?（）
