Identify and explain each of the types of delays that should be considered to calculate the total end-to-end delay to send a packet of length .

Directions: For each multiple-choice question, choose one of the options and explain your answer. Each multiple-choice question is worth 20 points.For the remaining questions, provide an explanation. Your explanation should be a minimum of one paragraph (four to five sentences). Include citations to all external references. Each of these questions is worth 30 points.The questions are listed below, but please use the Assignment #2 document to submit your answers.1. Routers operate at: (a) Layer 2 (b) Layer 3 (c) None of the above2. TCP and UDP operate at the following layer of the protocol stack: (a) Data link layer (b) Network layer (c) Transport layer3. Suppose there is exactly one packet switch between a sending host and a receiving host. The transmission rates between the sending host and the switch and between the switch and the receiving host are R1 and R2 respectively. Assuming that the switch uses store-and-forward packet switching, answer the following questions: a. Describe the functions of a store-and-forward packet switch. b. Identify and explain each of the types of delays that should be considered to calculate the total end-to-end delay to send a packet of length L. c. Explain the difference between variable and constant delays and identify which of the delays described in (b) are constant and which are variable.4. Describe the concept of encapsulation in layered architectures. Then, explain the importance and possible downsides of encapsulation in multi-layered architectures.