I would like to ask you a few questions about OSPF, I would like to thank you very much. 20

1. The next hop of RTA access network segment N is the interface on the left side of the RTB, and the next hop of RTB access N is the interface on the left side of the ABR.

2, LSA4 can flood to area0, as the RTA in area0 can of course be received. The answer to the next hop is the same as to question 1.

3. OSPF has two confirmation methods, one is implicit confirmation and the other is explicit acknowledgment. Needless to say, the implicit acknowledgment is done by the serial number, as shown in the figure, even the serial number is displayed in the SEP column.

1. The next hop of RTA to N is the interface on the left side of the RTB, and the next hop of RTB to N is the interface on the left side of the ABR.

2. LSA4 can flood to Area0, and RTA in Area0 can definitely receive LSA4The answer to the question about the next hop is the same as the first one.

3. OSPF has two confirmation methods: implicit confirmation and explicit acknowledgment. Needless to say, the implicit confirmation is carried out by the serial number, as shown in the OSPF topology table shown in the figure, the serial number is displayed in the SEQ column.

It's still useless, please help the heroes deal with it! To put it simply, there are also online words that delete IE temporary files, etc., and I try to do so.

Each router maintains a database within an autonomous system. And the database is the same, mainly including: the local routing status of each router, that is, the routers and networks it is directly connected to and the distance to them.

The link state of each router in an autonomous system is taken together to form the topology database of the autonomous system. Option B says that the link-state database of each router contains the topology of the region, so choose B

I think I choose A

b is right, the database of course includes the topology of the region, but there is also aggregate information outside the region. b doesn't say "contains" only, the description should be correct.

A is wrong, only flooding LSA2 within the region when the update is triggered. Updates received by out-of-zone routes are LSA3 sent by ABR.

The reason why B is wrong may be that LSDB only includes LSA and does not include topology information. The TOPO information is calculated by the SPF algorithm.

C and D definitely don't need to look at it, I also think A is wrong, and you can find that the TTL value of the update packet is 1, which means that it is only transmitted in the local subnet, not the whole network router. Like the previous digit, in B, the router in the region must have the topology information of the region, and the Type 1 and Type 2 LSAs are definitely flooded in the region, which is also the difference between LS and DV. I really can't think of why it's a b error.