Multiple choice Which of the following is/are correct about High Level Data Link Control (HDLC)? It is used to control transmission. It is a synchronous layer 2 wan protocol that uses polling to transmit data. It is used for a device running software that allows connection of two different environments. This protocol is used to restrict access to one network from another. All of the above Reveal answer Fill a bubble to check yourself A Correct answer Explanation HDLC adds error correction and flow control as well as response modes to control transmission.