問題文
A cluster carries one script that reshapes messages and another that passes proprietary headers between the legs. Which condition sets the second apart?
選択肢
- The script has to sit on a line rather than on a trunk, since a header of that kind reaches the cluster from an endpoint and never from a trunk.
- The script has to be one that came with the system, since only a supplied script is allowed to carry a header across from one leg to the other.
- The script has to be applied to the incoming direction, since a header is read on the way in and there is nothing left to read on the way out.
- Both of the legs of the call have to be SIP, since passing a header of that sort onwards has no meaning at all in a leg that speaks a different protocol.