Question 1 (3.5 points): Consider a datagram network using 32-bit host addresses. Suppose a router has four links, numbered 0 through 3, and packets are to be forwarded to the link interfaces as follows:
a. (2 points) Provide a forwarding table that has five entries, uses longest prefix matching, and forwards packets to the correct link interfaces.
b. (1.5 points) Describe how your forwarding table determines the appropriate link interface for datagrams with destination addresses: (determine datagram is forwarded to which interface)
Address 1: 11001000 10010001 01010001 01010101 --> Interface#:
Address 2: 11100001 01000000 11000011 00111100 --> Interface#:
Address 3: 11100001 10000000 00010001 01110111 --> Interface#:
Question 2 (3.5 points): Consider a subnet with prefix [url removed, login to view]
(.5 points) A) Provide the range of correct addresses
(of form [url removed, login to view]) that can be assigned to this network.
Answer: [url removed, login to view] - XXX
(3 points) B) Suppose an ISP owns the block of addresses of the form [url removed, login to view] Suppose it wants to create four subnets from this block, with each block having the same number of IP addresses. What are the prefixes (of form a.b.c.d/x) for the four subnets?
Question 3 (3 points): Consider the network setup in Figure 4.22. or the figure in the tutorial slide. Suppose that the ISP instead assigns the router the address [url removed, login to view] and that the network address of the home network is 192.168.1/24.
a. (1 point) Assign addresses to all interfaces in the home network. (hint: use 192.168.1.1 as the first address) (Use any correct addresses, so you can use it in the next step for NAT translation table)
1. Machine A
2. Machine B
3. Machine C
4. Router’s address (LAN interface)
b. (2 points) Suppose each host has two ongoing TCP connections, all to port 80 at host 220.127.116.11. Provide the six corresponding entries in the NAT translation table.
NAT TRANSLATION TABLE
WAN side addr (include ip/port) LAN side addr (include ip/port)