問題文
A carrier turns on the scheme that settles a route by stacking instructions onto a packet. Which protocol carries those instructions around the domain, and how much of them does one device come to know?
選択肢
- A protocol of its own has to be turned on beside them, since none of IS-IS, of OSPF and of BGP was ever given a way of carrying them, and every device of the domain comes to know every one of the instructions that every other device has put out
- A protocol of its own has to be turned on beside them, since none of IS-IS, of OSPF and of BGP was ever given a way of carrying them, and a device comes to know only the instructions of the devices it holds an adjacency with, the rest being kept from it
- The protocols already in use carry them, since the instructions go out as extensions of IS-IS, of OSPF and of BGP, and every device of the domain comes to know every one of the instructions that every other device has put out
- The protocols already in use carry them, since the instructions go out as extensions of IS-IS, of OSPF and of BGP, and a device comes to know only the instructions of the devices it holds an adjacency with, the rest being kept from it