Various mechanisms have been proposed to carry out the error-detection and correction process. One mechanism is to add sufficient check bits in the error checking field to correct a specified number of errors, and this is called FEC(Forward Error Correction) method. Another mechanism is to detect the errors and correct them by retransmission, and this is commonly called ARQ(Automatic Repeat reQuest). Three types of ARQ procedures are possible, these are : SW(Stop and Wait), GB(N)(Go Back N) and SR(Selective Repeat) protocols. Many studies on these protocols of ARQ are for about only data packets or messages. In this paper, we are concerned with the GB(N) ARQ protocol under Markovian interruptions. The data packets can not be transmitted when the Markovian interruption exists. We calculate the average queue length of buffer and the average waiting time of a data packet of GB(N) ARQ protocol under Markovian interruptions. The input process is a Poisson process and the discrete time queueing model is used for analyzing the queue behavior. Comparing the results of queue behavior with or without Markovian interruptions, we also investigate the effect of Markovian interruption. The analysitic results are verified by computer simulations. The results of this can be utilized in the analysis of voice/data multiplexers.