1. What are the five layers in the Internet protocol stack? (5) What are the principal responsibilities of each of these layers? [10] 2. Explain the concept of encapsulation in networking discipline? 3. True or False Host breaks applications messages into packets. TCP/IP protocol stacks describes the Internet structure. The upper three layers of the OSI layering model correspond to the top TCP/IP model. Network layer is commonly named IP layer. Communication between two hosts starts from the physical layer. Different application protocols needed for different physical links. 4. Consider sending a packet from a source host to a destination host over a fixed route. List the delay components in the end-to-end delay [2]. Which of these delays are constant and which are variable?[1] [1/3] 5. Describe the "Store-and-forward" concept in packet switching network. To what type of delays it contributes? [/4]