Nt2580 Unit 6 Lab 1

MANAGEMENT INFORMATION SYSTEMS OMIS 660 FALL 2015 Instructor – Dr. Yipeng Liu

LAB 1 – TCP: TRANSMISSION CONTROL PROTOCOL

Submitted by: Submission Date: 09-25-2015
Divya Malika Vandana
Z1776136
Divya Reddy Chandupatla
Z1768598

SUMMARY
In this lab, we used Transmission Control Protocol (TCP) which is a connection oriented protocol, to demonstrate congestion control algorithms. As the name itself describes, these algorithms are used to avoid network congestion. The algorithms were implemented in three different scenarios i.e. No Drop Scenario, Drop_Fast Scenario and Drop_NoFast Scenario.

According to the manual, we chose USA from the map list and created a network. • As shown in the picture below, we added Application config, Profile config, ip32_Cloud and two subnets into the project workspace.

• The next step is to set the names of the devices on the network and edit their attributes.
• For the Application config, the name is set to APPLICATIONS. The attributes are edited as shown in the picture below.
Here, the number of rows of Applicaion definition is set to 1 since we are using a single application i.e. FTP. The name of application is given as FTP_Application. In the description of FTP inter request time, the time taken to transfer the file, is set to constant (3600) and the File size is set to constant (10000000) which is 10MB.

• For the Profile config, the name is set to PROFILES and the attributes are edited as shown in the picture below.
Here, the number of rows for profile config is set to 1 and the name is given as FTP_Profile.

• For the west subnet, one ethernet_server and one ethernet4_slip8_gtwy router are connected with a bidirectional 100 BaseT link. The attributes of the server are shown in the picture

3. DROP FAST SCENARIO

For Drop_Fast scenario, we change the flavour of the TCP Properties to Reno for fast recovery and fast retransmit mechanism. When there is loss of packet, the sender doesn’t wait for the time out and resends the packets immediately using the mechanism of fast recovery and fast retransmit.
Analysing the graph, since there are loss of packets and retransmission, the congestion window size graph fluctuates by increasing and decreasing very frequently.

4. COMPARISION OF THE THREE SCENARIOS
The graph shows comparison of the three scenarios for sent segment sequence number. The green curve represents No_Drop scenario where it shoots up as it is a perfect scenario where there is no loss of packets. Whereas the blue curve which representd Drop_Fast Scenario increases exponentially because there is loss of packets and retransmission takes place.