Bit Stuffing in Computer Network Using Python

Bit Stuffing Mechanism

Here, the delimiting flag sequence generally contains six or more consecutive 1s. Most protocols use the 8-bit pattern 01111110 as flag. In order to differentiate the message from the flag in case of same sequence, a single bit is stuffed in the message. Whenever a 0 bit is followed by five consecutive 1bits in the message, an extra 0 bit is stuffed at the end of the five 1s. When the receiver receives the message, it removes the stuffed 0s after each sequence of five 1s. The un-stuffed message is then sent to the upper layers.

 

Code :

#Stuffing the original signal def stuff(sig): onec = 0 # one counter c = 0 # index counter one = [] # one indexes s = list(sig) for i in s: c += 1 if i == '0': onec = 0 else: onec += 1 if onec == 5: one.append(c) onec = 0 k = 0 # count extra index number for i in one: # print(i) s.insert(i+k,'0') k+=1 return s # destuffing the stuffed signal def destuff(sig): onec = 0 # one counter c = 0 # index counter one = [] # one indexes sig = list(sig) for i in sig: c += 1 if i == '0': onec = 0 else: onec += 1 if onec == 5: one.append(c) onec = 0 k = 0 # count extra index number for i in one: # print(i) sig.pop(i+k) k-=1 return sig # Driver Code sig = input("Enter the signal: ") print("Original Signal : ",sig) stf = stuff(sig) print("Stuffed Signal : ",end ="") print("".join([ x for x in stf])) dstf = destuff(stf) print("Destuffed Signal : ",end ="") print("".join([ x for x in dstf]))