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View Global Node: View and control detailed information available on the Global Node (GN)

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The goal of this exercise is to introduce you to what the GENI Desktop and GEMINI refer to as that Global Node (GN). The GN is an extra node (VM) that is automatically added to your slice when you select the GEMINI extensions in Flack (or manually add the GEMINI extensions into an RSPEC). The purpose of the GN is to be the collection point for all instrumentation and measurement data collected by the slivers. Since slivers may be in different aggregates, there is one GN per aggregate. Each GN only collects data from slivers in its aggregate. This localizes communication, thereby minimizing interference of the I&M data collection mechanism with the running experiment. It also provides a centralized location(s) where users can go to find detailed information coming from the slivers in an aggregate.

In this exercise you will use the GENI Desktop to connect to the GN an view live graphs and tables from the running experiment, you will also

Ssh'ing into nodes from the GENI Desktop

To open an ssh session, you must first launch the ssh tool. You can launch the ssh tool by clicking the launch icon in the upper lefthand corner of the GENI Desktop and then selecting ssh. This will create an ssh button No image "ssh.png" attached to GENIExperimenter/Tutorials/GENI_Desktop_and_GEMINI_tables/ExecuteExperiment near the task bar on the bottom. To ssh into nodes, select the node in the topology by left-clicking on the node. Once selected, press the ssh button to ssh into your network. You may need to accept the security certificate if prompted by your browser. You can iconify the ssh button or deiconify the ssh button by clicking ssh in the task bar.

Viewing traffic from the GENI Desktop

To view traffic, click on the launcher icon and select gemini graphs. This will create a graph selection window (see below) on your screen. By default, the CPU, ICMP, and IP graphs are selected. Adjust the selection to the graphs you want to see. Select the node or nodes in the topology for which you would like to see graphs. Then click the "add graphs" button. If you have selected multiple nodes, you may prefer to click on "add graphs with titles," as this will clearly identify the node from which the graph is taken. Like the ssh box, you can iconify or deiconify the graph selection box by clicking on the task bar.

No image "graphselect.png" attached to GENIExperimenter/Tutorials/GENI_Desktop_and_GEMINI_tables/ExecuteExperiment

Generating traffic with iperf

The iperf program can be used to generate traffic. Iperf needs to be run on both the source and destination node. Iperf should first be started at the destination in server mode using the command "iperf -s." To run iperf on the source, type "iperf -t 60 -b 100M -c destination" where destination is the IP address (or name) of the node where the iperf server is running. This will tell iperf to generate traffic for sixty seconds, sending at a rate of one hundred megabits per second. The names of the hosts in your topology can be found in the /etc/hosts.

Exercise Tasks

  1. Task 1: Ssh into VM-0 and VM-1.
  2. Task 2: Use iperf to generate traffic between VM-0 and VM-1.
  3. Task 3: View the traffic between VM-0 and VM-1.

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