单项选择题 An enterprise has plans to start adding IPv6 support. The initial deployment requires support from some IPv6 - only device s that need to access servers that support only IPv4. Which of the following tools would be most appropriate?（）

单项选择题 An enterprise h as plans to start adding IPv6 support. For the first year, the IPv6 will be in small pockets spread around the existing large IPv4 network, with occasional IPv6 traffic while applications teams test IPv6 - enabled servers and applications. Which of the fol lowing tools would be most appropriate?（）

单项选择题 Router R1 has been conf igured with an ipv6 route 2000::/64 S0/0/0 64 command.Which of the following does the 64 at the end of the command represent?（）