多项选择题 In IPv6 network, an IPv6 overlay tunnel is required to communicate with isolated IPv6 networks across the existing IPv4 infrastructurE. There are currently fiv e IPv6 overlay tunnel types. Which three IPv6 overlay tunnel statements are true？（）

单项选择题 Which statement describes the difference between a manually configured IPv6 in IPv4 tunnel versus an automatic 6to4 tunnel?（）

多项选择题 Which two statements are true about using IPv4 and IPv6 simultaneously on a network segment? （）