Assignment 2
1. Sketch the header format of IPv4 datagram with detailed explanation of each field. Highlight
the importance of fragmentation offset and TTL field.
2. What is the difference between Segmentation and fragmentation. An IP packet of size 1600
bytes passes through network segment before it reaches its destination.The header size of
this packet is 30 bytes. The maximum size of an IP packet in intermediate network (MTU) is
1400 bytes. How the IP packet would be fragmented in a router. Find all the information for
each fragment.
3. Consider the effect of using slow start on a line with a 10-msec round-trip time and no
congestion. The receive window is 24 KB and the maximum segment size is 2 KB. How
long does it take before the first full window can be sent?
4. Suppose a router has built up the routing table shown in Routing Table. The router can
deliver packets directly over interfaces 0 and 1, or it can forward packets to routers R2, R3,
or R4. Assume the router does the longest prefix match. Describe what the router does with
a packet addressed to each of the following destinations:
i. 128.96.171.92
ii. 128.96.167.151
iii. 128.96.163.151
iv. 128.96.169.192
v. 128.96.165.121
Routing Table
Subnet Number Subnet Mask Next Hop
128.96.170.0 255.255.254.0 Interface 0
128.96.168.0 255.255.254.0 Interface 1
128.96.166.0 255.255.254.0 R2
128.96.164.0 255.255.252.0 R3
Default R4
5. An ISP is granted the block 80.70.56.0/21. The ISP needs to allocate addresses for two
organizations each with 500 addresses, two organizations each with 250 addresses, and three
organizations each with 50 addresses.
• Find the number and range of addresses in the ISP block.
• Find the range of addresses for each organization and the range of un-allocated
addresses.
• Show the outline of the address distribution and the forwarding table.
6. Use Dijkstra’s algorithm to find the shortest path tree and the forwarding table for node A in
the following Figure.
1. Sketch the header format of IPv4 datagram with detailed explanation of each field. Highlight
the importance of fragmentation offset and TTL field.
2. What is the difference between Segmentation and fragmentation. An IP packet of size 1600
bytes passes through network segment before it reaches its destination.The header size of
this packet is 30 bytes. The maximum size of an IP packet in intermediate network (MTU) is
1400 bytes. How the IP packet would be fragmented in a router. Find all the information for
each fragment.
3. Consider the effect of using slow start on a line with a 10-msec round-trip time and no
congestion. The receive window is 24 KB and the maximum segment size is 2 KB. How
long does it take before the first full window can be sent?
4. Suppose a router has built up the routing table shown in Routing Table. The router can
deliver packets directly over interfaces 0 and 1, or it can forward packets to routers R2, R3,
or R4. Assume the router does the longest prefix match. Describe what the router does with
a packet addressed to each of the following destinations:
i. 128.96.171.92
ii. 128.96.167.151
iii. 128.96.163.151
iv. 128.96.169.192
v. 128.96.165.121
Routing Table
Subnet Number Subnet Mask Next Hop
128.96.170.0 255.255.254.0 Interface 0
128.96.168.0 255.255.254.0 Interface 1
128.96.166.0 255.255.254.0 R2
128.96.164.0 255.255.252.0 R3
Default R4
5. An ISP is granted the block 80.70.56.0/21. The ISP needs to allocate addresses for two
organizations each with 500 addresses, two organizations each with 250 addresses, and three
organizations each with 50 addresses.
• Find the number and range of addresses in the ISP block.
• Find the range of addresses for each organization and the range of un-allocated
addresses.
• Show the outline of the address distribution and the forwarding table.
6. Use Dijkstra’s algorithm to find the shortest path tree and the forwarding table for node A in
the following Figure.
