Most of today's internet uses IPv4, which is now more than twenty years old. IPv4 has been(72) resilient in spite of its age, but it is beginning to have problems. Most importantly, there is a growing(73) of IPv4 addresses, which are needed by all new machines added to the Internet. IPv6 fixes a number of problems in IPv4, such as the(74) number of available IPv4 addresses. It also adds many improvements to IPv4 in areas such as routing and network autoconfiguration. IPv6 is expected to gradually replace IPv4, with the two coexisting for a number of years during a transition(75) .
A.substitution
B.swap
C.switchover
D.replace
为了保护您的账号安全,请在“上学吧”公众号进行验证,点击“官网服务”-“账号验证”后输入验证码“”完成验证,验证成功后方可继续查看答案!