Homework 6 Problem 1 – 5 Solution



Suppose an application generates chunks of 60 bytes of data, each chunk gets encapsulated in a TCP segment, and then an IP datagram.

  1. What percentage of each datagram will be overhead, and what percentage will be application data?

  1. What would be the overhead if each TCP segment include 100 of application chunks (i.e., 100 60 bytes), assuming the maximum size of an IP packet is 500 bytes and sending such big TCP payload would require fragmentation.

Write your answer here

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CS 118 Winter 2019 : Homework 6

Problem 2

Consider the router trying to send the following IP packet:








0 0 0



data (6103 bytes)

Figure 1: An IP packet.

Assuming that the maximum transmission unit that can be transferred over the link is 1400 bytes. For each of the fragment show the header length, total length, identi cation, ags, fragment o set, TTL, protocol elds, and IP payload size.

Write your answer using the table below

Header length Total length Identi cation Flags Fragment o set TTL Protocol Data size

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CS 118 Winter 2019 : Homework 6

Problem 3

Calculate the network mask, the number of bits of the network, the number of endpoint addresses in the network (excluding special addresses), the network address, and the broadcast address of the network for the following:




  1., netmask

  1., netmask

Write your answer here

Problem 4

Why is the IP header checksum recalculated at every router?

Write your answer here

Problem 5

Install Wireshark (https://www.wireshark.org/). Then, (i) start capturing a packet trace from your network interface, (ii) open a web browser, (iii) go to https://www.cs.ucla.edu/, (iv) and then stop capturing the trace.

Investigate any TCP packet from your network interface to the UCLA CS web server. What is the IP address of your network interface? What is the IP address of www.cs.ucla.edu? Provide the screenshot that shows the IP addresses in the investigated packet.

Write your answer here (Also, attach the screenshot)

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