The latter two are simply the "inverse" of the first two, the only difference being whether the end point in question is on the receiving or sending end of the initial message.

后两种与前两种是简单“对立”关系，唯一的区别在于有问题的端点是在初始消息的接收端还是发送端。

youdao

The latter two are simply the "inverse" of the first two, the only difference being whether the end point in question is on the receiving or sending end of the initial message.

后两种与前两种是简单“对立”关系，唯一的区别在于有问题的端点是在初始消息的接收端还是发送端。

youdao