![](https://lstatic.shangxueba.com/sxbzda/h5/images/m_q_title.png)
● The usual way to ensure reliable delivery is to provide the (71) with some feedback abou
frame. to (74) completely. In this case, the receiver will not react at all, since it has no any reason to react. It should be clear that a protocol in which the sender transmits a frame. and then waits for an acknowledgement, positive or negative, will hang forever if a frame. is ever lost due to, for example, (75) hardware.
(71)
A. receiver
B. controller
C. sender
D. customer
(72)
A. data
B. control
C. request
D. session
(73)
A. application
B. connection
C. stream
D. acknowledgement
(74)
A. vanish
B. vary
C. appear
D. incline
(75)
A. acting
B. working
C. malfunctioning
D. functioning
![](https://lstatic.shangxueba.com/sxbzda/h5/images/tips_org.png)