= [.. Lab Zero: A First Experiment Using GENI] = {{{ #!html
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}}} == 4. Configure and Initialize == Now that you have reserved your resources, you are ready to run your first GENI experiment. === 4.1 Login to nodes === {{{ #!html
  1. Establish an SSH connection to both of the reserved nodes (client and server). To get login information for a VMs from the Slice page, either click on the "Details" button or click on the node and scroll through the information on the left. In addition, depending on the configuration of your system, you may be able to click on the SSH button. If you are using ExoGENI resources, you may need to reload the Slice page in your browser to see SSH information.

Login information for a VM
Figure 4-1 Login to a VM.
Tip To ssh from the command line on unix-based machines, do the following (substituting the values shown on the screen):
ssh USERNAME@HOSTNAME -p PORT
Tip To ssh from Windows machines, launch your favorite ssh client and substituting the values shown on the screen.
}}} == 5. Execute Experiment == === 5.1 Send IP traffic === The first simple experiment that we will run is to verify the IP connectivity between our hosts. a. Check the interfaces of your nodes. In each terminal type: {{{ sudo ifconfig }}} You should see at least two interfaces: * The '''control interface'''. This is the interface you use to access the node, e.g. ssh into your host. The control interface is mainly used for control traffic, i.e. traffic for controlling the node and the experiment. (likely something like 172.17.1.9) * The '''data interface'''. This is the interface that is used for sending experimental traffic. This is the interface that connects to the other hosts of your experiment through GENI. The links between these interfaces are the ones that allow you to run non-IP experiments. '''The data interface is the one that has an IP address and mask that match what you configured before you reserved your resources.''' (likely something like 10.10.1.2) b. Fill in the worksheet, noting the name and IP address of the control and of the data interfaces for each node. {{{ #!html
Tip The command prompt on each node may say "client" or "server" respectively.
}}} c. From the client, `ping` the server '''data plane interface'''. From the terminal window that is logged in to the client type : {{{ ping -c 5 }}} For example: {{{ ping 10.10.1.2 -c 5 }}} d. Now, `ping` the server '''control plane interface'''. From the terminal window that is logged in to the client type : {{{ ping -c 5 }}} For example: {{{ ping 172.17.1.9 -c 5 }}} === 5.2 Install and use `iperf` === a. Install the `iperf` software on both nodes: {{{ sudo apt-get install iperf }}} b. On both nodes run the hash command to ensure the new iperf command is accessable from the command line: {{{ hash }}} c. Start an `iperf` server on the server node: {{{ iperf -s }}} d. Run an `iperf` client via the data plane: {{{ iperf -c }}} For example: {{{ iperf -c 10.10.1.2 }}} ''What is the bandwidth of this link?'' [[br]] ''Why?''[[br]] [[br]] e. Run an `iperf` client via the control plane: {{{ iperf -c }}} For example: {{{ iperf -c 172.17.2.2 }}} ''What is the bandwidth of this link?'' [[br]] ''Why?'' [[br]] [[br]] f. Type `CTRL-C` on the server node to stop the `iperf` server. === 5.3 Bring down the server's data interface === a. (Only run this step if you selected an ExoGENI aggregate when requesting resources) ExoGENI nodes run a service called "neuca" that managed network interfaces on the node. To manually adjust the IP address, we must first disable neuca on both nodes. {{{ sudo service neuca stop }}} {{{ #!html
ExoGENI The ExoGENI "neuca" service controls a variety of network configuration details.
}}} b. From the client node, start pinging the server '''data plane interface''': {{{ ping }}} c. On the server node, bring down the '''data plane interface''' (being careful to disable the data interface NOT the control interface): {{{ sudo ifconfig down }}} ''After you bring down the data interface, the pings should indicate that the destination is unreachable.'' ''Why?'' {{{ #!html
Warning Be extra careful to disable the IP on the data interface, bringing down the IP on the control interface means that you will lose connectivity to your host.
}}} === 5.4 Bring down the server's control interface === a. From the client node, start pinging the server '''control plane interface''': {{{ ping }}} b. From the server node, bring down the '''control plane interface''' and try to ping it from the client node: {{{ sudo ifconfig down }}} ''Your ssh session should immediately hang.''' ''Why?'' ''After you bring down the control interface, the pings should indicate that the destination is unreachable. Why?'' {{{ #!html
Tip In general, in order to recover from a situation like this where you've lost the ability to login to your nodes, the best way to recover is to delete your resources and start again.
}}} == 6. Analyze Experiment == Now is when you would ordinarily analyze the results of your experiment. === 6.1 Logout of your nodes === * Then type `exit` in your open terminal. Congratulations you have run an experiment in GENI! ---- = [wiki:GENIExperimenter/Tutorials/jacks/GettingStarted_PartI/Procedure/DesignSetup Setup] = = [wiki:GENIExperimenter/Tutorials/jacks/GettingStarted_PartI/Procedure/Finish Next: Finish] =