Please answer the following questions related to Resource Reservation Protocol (RSVP). a. What does the reservation message create and maintain in each node along its path? b. The reservation message is sent by the receiver to the sender. What is the reason for doing so? c. RSVP takes a soft state approach to manage the reservation state. Briefly describe what soft state is and the reason for using it. d. As shown in Figure 6, H1 to H4 are both senders and receivers, with IP addresses of IP-H1 and IP-H4. H1 and H2 belong to multicast group M1 (IP address: IP-M1), H3 and H4 belong to multicast group M2 (IP address: IP-M2). Is it possible for H1 to send a packet to H4 using multicast? Please briefly explain your answer. Also, if your answer is yes, please specify the source IP and the destination IP in the header of the packet. If your answer is no, please suggest a method to make it possible. e. Please write down a possible IP address (e.g., in the form of x.x.x.x) for IP-M1. H2 H1 L2 R1 L6 R2 Figure 6 L7 R3 L3 L4 H3 H4