大部分的通信都不是一方只是发送，而另一方只是接收，而是双向的。因此在这种情况下返回的Ack帧通常可由反向发送的数据帧一起捎带回来。这只要在数据帧中再加一个确认帧号就可以了。这种技术称作捎带确认。-Most of the communication is not a party to only send, while the other is only receiving, but the two-way street. Therefore, in this case to return to the Ack fr a me is usually sent by the reverse data fr a mes back together incidentally. This is as long as the fr a me in the data fr a me by adding a confirmation number on it. This technology, known as piggybacking confirmed.