問題文
A large autonomous system is being split into areas of this protocol because the shortest path work grows too heavy for one common database. Does any one of the areas serve strictly as a backbone, and how much of the database does a single router within a level come to hold?
選択肢
- None of the areas serves strictly as a backbone, and it is the routers of the higher level that carry reach from one area over to another, and a router within a level holds a complete database of the other routers of that level and runs the shortest path work over it
- None of the areas serves strictly as a backbone, and it is the routers of the higher level that carry reach from one area over to another, and a router within a level holds only the part of the database that covers its own neighbors and asks them for whatever else it comes to need
- One of the areas serves strictly as a backbone, and every other area has to be joined to it through a router that holds the higher level, and a router within a level holds only the part of the database that covers its own neighbors and asks them for whatever else it comes to need
- One of the areas serves strictly as a backbone, and every other area has to be joined to it through a router that holds the higher level, and a router within a level holds a complete database of the other routers of that level and runs the shortest path work over it