As shown in the figure, all interfaces of the router enable OSPF, among which R4 and R5 can establish OSPF virtual connections.

A router Network LSA is shown in the figure. Which of the following statements is correct? (Multiple choice)

The network administrator A wants to use ACL to match only the four routing entries 1, 3.5, and 7 in the figure. How many ACL rules does the network administrator A need to configure at least?

Which LSA in OSPFv3 can be flooded within an area?

IS-IS is a link state routing protocol that uses the SPF algorithm for routing calculations. A park has deployed IPv4 and IPv6 at the same time and runs IS-IS to achieve network interconnection. As shown in the figure, the network IPv4 and IPv6 have the same overhead, and R1 and R4 only support IPv4. By default, in the calculated IPv6 shortest path tree, the next hop device for R2 to access R6 is () (Note: The device name must be consistent with the figure, such as: R1)