問題文
A transit provider offers its customers two of the actions in its published table: one keeps a route from being announced to external neighbors in a named country, and one lowers the degree of preference of a route. The note has to record how far the first one reaches and what to watch for with the second. Which statement is correct?
選択肢
- The first does not stop a neighbor from learning the route elsewhere and making it available in that country, and the second is safe in itself, and the degree of preference that it changes is not carried outside the system that sets it.
- The first also fails to stop announcements to internal neighbors in that country, and the second is safe in itself, and the degree of preference that it changes is not carried outside the system that sets it.
- The first also fails to stop announcements to internal neighbors of the same operator in that country, and the second can push a route below another class of route and leave the whole network in a state that nobody intended.
- The first does not stop a neighbor from learning the route elsewhere and making it available in that country, and the second can push a route below another class of route and leave the network in a state nobody intended.