Lab6 - Lab Report 6 TCP Study Due 20th November 2015[11...

Info icon This preview shows pages 1–4. Sign up to view the full content.

Lab Report 6 TCP Study Due 20 th November 2015 [11 Pages] TCP connection control Exercise 1 In this exercise, our goal is to understand the process of TCP connection establishment and termination. While running sudo tcpdump host <your_host_ip_address> and <your_remote_host_ip_address> -w exe1.pcap in your host, open another terminal window and execute telnet <your_remote_host_ip_address> Then, without typing anything else, e.g. username or password , kill the telnet program (and therefore the established TCP connection) by pressing Control + c . Save the tcpdump output. LAB REPORT: (a) Explain TCP connection establishment and termination using the tcpdump output. TCP connection establishment:
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

The TCP connection establishment is performed by a three-way handshake mechanism. The TCP header consists of the source and destination port numbers that identify the application processes on either end. 1. The client sends a SYN (synchronous) message, which contains data like MSS (Maximum Segment Size), TCP receiving window size and initial sequence number. The SYN flag bit is set to indicate a connection request. 2. The server needs to acknowledge the SYN packet sent by the client and sends its own SYN packet to the client, with its own initial sequence number, MSS and TCP receiving window size. It sends both the acknowledgement and SYN message in a single segment. 3. The client will now send an acknowledgement for the Server’s SYN message, with the ISN increasing by +1. 4. After this the connection is established, and the data transfer begins between the Server and Client, with each data transfer being followed by it’s acknowledgement. TCP Connection Establishment TCP Connection termination : TCP adopts a four-way handshake to terminate the connection, which allows each end to shut the one way data flow if only one end has data to send. 1. Here, the server closes the connection, so Othello sends a packet with FIN flag set, along with the acknowledgement of the previous data received. 2. Now, the client Desdemona sends a packet with FIN flag set and ACK for the server’s termination data. 3. Finally, the server sends an ACK for the client’s FIN data, terminating the connection on both ends. TCP Connection Termination
Image of page 2
(b) What were the announced MSS values for the two hosts? The MSS values for the two hosts is 1460 bytes. (c) What happens if there is an intermediate network that has an MTU less than the MSS of either host, given that the DF flag is set in the IP header? What if it is not set? If there is an intermediate network that has an MTU less than the MSS of either host, it gets fragmented and sent in different packets if the DF flag is not set in the IP header. It gets dropped if the DF flag is set in the IP header. Exercise 2 In this exercise, our goal is to see what happens if the client tries to reach an unused port at the server side.
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Image of page 4
This is the end of the preview. Sign up to access the rest of the document.
  • Spring '14
  • Transmission Control Protocol, tcpdump output

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern