Creating Inter-aggregate Links (with CCNX)


In this experiment you will learn how to draw topologies that connect nodes at different aggregates (in different geographic locations). We will use the following network topology for this experiment:
route topology


For this tutorial you need :


We will use the following tools:

Where to get help:

  • Contact your TA and/or Professor for help. If you are doing this exercise outside the context of a course, please email


1. Verify your Environment Setup:

This exercise assumes you have already setup your account at the GENI Portal. In particular ensure that:
  1. You can login to the GENI Portal
  2. You are a member of a GENI Project (there is at least one project listed under the ''Projects'' tab)
  3. You have setup your ssh keys (there is at least one key listed under the ''Profile->SSH Keys'' tab)

2. Setup the Topology:

2b. Add a second site:

  1. Login to the GENI Portal
  2. Create a new slice with the name of your choice.
  3. Click the Add Resources button on the Slice page.
  4. Load your 5 node RSpec from before or use:
  5. Drag a second site onto the canvas.
  6. Drag ccnx-router-1 and user-0 to the second site.
  7. When we are done, we will have a total of 6 nodes with 3 nodes at each site. Set the NUM_NODES parameter of ccnx-setup to 3 on all the nodes. Also adjust the BARRIER_NODE for the nodes in the new site.
    1. On nodes in the first site, leave the BARRIER_NODE unchanged and set NUM_NODES to be 3.

      The new execute command on all of data, ccnx-router and user should be:
      cd /tmp/ccnx-setup && ./ccnx-setup ccnx-router 3
    2. On the nodes at the second site, change the BARRIER_NODE to ccnx-router-1 and set NUM_NODES to be 3.

      The new execute command on both of ccnx-router-1 and user-0 should be:
      cd /tmp/ccnx-setup && ./ccnx-setup ccnx-router-1 3
  8. Use the Duplicate button to copy user-0. (Feel free to change it's name.)
  9. Draw a link between the new user node and ccnx-router-1
  10. Auto-IP all of the links.
  11. Instead of setting the NEXT_HOP on ccnx-router-1 to ccnx-router use it's data plane IP address (from the link between the two ccnx-router nodes).

    The new add-precip-routes execute command on ccnx-router-1 should be as follows (be sure to substitute the appropriate IP address):
    cd /tmp/ccnx-setup && ./add-precip-routes
route topology
Figure 1 The 6 node topology.

2b. Make the link be stitched:

  1. Click on the unlabeled box in the middle of the link. Select "Stitched Ethernet" as the link type.
route topology
Figure 2 Set the Link Type on the inter-aggregate link.
The link type you select will affect the aggregates you are allowed to bind to in the next step.
  • Stitched Ethernet gives you a layer 2 link (i.e. a VLAN) between aggregates.
  • EGRE Tunnel gives you a layer 3 tunnel between aggregates.
  • However, if you would like a Layer 2 link connecting only ExoGENI sites, instead set the Link Type to "(any)" and pick any two ExoGENI aggregates except "ExoGENI ExoSM".
  1. Bind each site to an aggregate. (If you are doing this as part of a tutorial, use the aggregates specified on your worksheet.)
  2. Click Reserve Resources.
route topology
Figure 3 Bind the sites. The aggregate choices will be limited based on the link type.
  1. The reservation may take a couple of minutes to complete. After the reservation completes, return to the slice page.
  2. While you are waiting for the nodes to be ready, click the Geo Map button. Wait for this page to load to see where your nodes are geographically located. Note that it may take a moment for your nodes to be drawn.
route topology
Figure 4 The geographical location of your nodes.
  1. Press the back button on your browser to return to the slice page. Wait for the nodes to be ready.
route topology
Figure 5 The stitched topology is ready and green.


3. Test Connectivity

  1. Log into the various user nodes and run /opt/ccnx-atmos/ Does it behave the way you would expect?
  2. (optional) You can use GENI Desktop to visualize the flow of the traffic.


4. Cleanup

After you are done with the exercise, delete your resources:
  1. Click on a blank part of the canvas, then press the Delete button. When prompted, confirm you want to delete all of the resources in the slice.
  2. After a few moments all the resources will have been released and you will have an empty canvas again.
Last modified 7 years ago Last modified on 06/14/15 23:19:49

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