問題文
A campus writes one line that turns away the traffic of a chosen kind toward one server by naming the number of the door at the far end, and it writes another line that lets the traffic of the same kind through toward that server without naming a door. Some of the packets that reach the box arrive in pieces. What does the guide say the two lines do with the pieces that carry no number of a door?
選択肢
- The line that turns traffic away passes over such a piece while the line that lets traffic through takes it, because a turning away that reads a door is met only where the door stands in the piece.
- Both of the lines pass over such a piece, because a line that reads anything above the third layer is met only where the whole of a packet has arrived at the box in one piece.
- Both of the lines take such a piece, because the box holds the pieces of a packet until the first of them has arrived and reads the number of the door from it.
- The line that turns traffic away takes such a piece while the line that lets traffic through passes over it, because a turning away that reads a door is met wherever the pieces of a packet reach the box.