1. A bit string, 011111101111101111110, needs to be transmitted at the data link layer. What is the string actually transmitted after bit stuffing? Underline the additional bits you insert. 2. When should a selective repeat protocol be used versus a go-back-n protocol. 3. Specify the fields that make up a Point-to-Point protocol [PPP] frame. 4. Provides a simple parametric formula to quantify the size [in bytes] of a PPP frame. 5. A 100-km-long cable runs at the T1 data rate. The propagation speed in the cable is 2/3 the speed of light in vacuum. How many bits fit in the cable?