wiki:GENIExperimenter/ExperimentExample-OF

Version 1 (modified by lnevers@bbn.com, 8 years ago) (diff)

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GENI OpenFlow Experiment Example 2

This page illustrates an operational OpenFlow (OF) example for the GENI Experimenter How-to page.

OpenFlow is used for control of many of the network resources in the GENI backbone and at meso-scale campus locations. Many experimenters will can use these GENI resources without learning OpenFlow. The GPO help@geni.net can help arrange connectivity across your GENI slice, including IP connectivity and/or layer 2 VLANs.

For experimenters who desire control over the network switching fabric in their slices, OpenFlow provides increased flexibility. Your experiment will incorporate an OpenFlow controller. If you have never written a controller, don't panic. Many experiments can use existing controller code as-is, or with relatively simple modifications. The GPO is available to help design your controller and plan your experiment configuration. Feel free to contact us at help@geni.net.

The example captured in this page uses credentials from pgeni.gpolab.bbn.com, the GPO ProtoGENI Clearinghouse, to set up an experiment that includes 3 fictional sites (1 PG and 2 MyPLC nodes). This examples assumes that a OF Controller, such as NOX, is running on a slice resource, and is available and is accessible to the FlowVisor instances. In this scenario, two sites are Web Servers and 3 are clients, as shown in the diagram below:

No image "OF-Experiment-example.jpg" attached to GENIExperimenter/ExperimentExample-OF

Omni tools can be used to reserve OF resources in each of the site's OpenFlow Aggregate Manager (OF AM). Steps that are to take place include:

  • Configure Omni tools
  • Define OpenFlow RSPEC
  • Request flowspace resources
  • Opt-in Manager Administrative approval
  • Run the experiment

Note: Open Flow Aggregate Manager sites must be federated in order to trust a Clearinghouse. This is an OF administrator task that must take place before any of the user OF operations can take place.

Authentication and Omni tools configuration

This example assumes that GENI credentials have been set up as detailed in the GENI Credentials section of the main GENI Experimenter page.

The settings as defined in the Omni Configuration section of the non OF GENI Experiment Example will work for this OF set up. The credentials from from the GPO Clearinghouse will allow access to the GPO OF aggregate manager. A list of Aggregate managers is being compiled in the GENI Aggregate page, if your site is not listed on this page you should contact you site administrator, or the GPO at help@geni.net.

Determine Resources

An OpenFlow RSPEC must be defined for each of the 3 site OF AM in order to get access to the OF resources. The content of the OF RSPEC depends on the type OF AM resource that you may need. You may need to define an RSPEC using any of the following:

  • IP Addresses
  • MAC Address
  • Data Path Identifier (DPID).

To find out what OF resources are available from each of the OF Aggregate Manager, you may use Omni tools to get a list of available resources. Here is an example of resources the OF Aggregate Manager for Site 1 in native RSPEC format:

$ ./src/omni.py -n -a https://ofam1.site1.com:1443/openflow/gapi/ listresources
INFO:omni:Loading config file omni_config
INFO:omni:Using control framework pgeni
INFO:omni:Resources at https://ofam1.site1.com:1443/openflow/gapi/:
<?xml version="1.0" ?>
<rspec type="openflow">
  <network location="Cambridge MA" name="local-oim">
    <switches>
      <switch urn="urn:publicid:IDN+ofam1.site1.bbn.com:expedient:openflow+switch:044:d0:02:6f:13:f3:b0:0">
        <port urn="urn:publicid:IDN+ofam1.site1.bbn.com:expedient:openflow+switch:044:d0:02:6f:13:f3:b0:0+port:26"/>
        <port urn="urn:publicid:IDN+ofam1.site1.bbn.com:expedient:openflow+switch:044:d0:02:6f:13:f3:b0:0+port:27"/>
        <port urn="urn:publicid:IDN+ofam1.site1.bbn.com:expedient:openflow+switch:044:d0:02:6f:13:f3:b0:0+port:28"/>
        <port urn="urn:publicid:IDN+ofam1.site1.bbn.com:expedient:openflow+switch:044:d0:02:6f:13:f3:b0:0+port:29"/>
        <port urn="urn:publicid:IDN+ofam1.site1.bbn.com:expedient:openflow+switch:044:d0:02:6f:13:f3:b0:0+port:43"/>
        <port urn="urn:publicid:IDN+ofam1.site1.bbn.com:expedient:openflow+switch:044:d0:02:6f:13:f3:b0:0+port:44"/>
        <port urn="urn:publicid:IDN+ofam1.site1.bbn.com:expedient:openflow+switch:044:d0:02:6f:13:f3:b0:0+port:45"/>
        <port urn="urn:publicid:IDN+ofam1.site1.bbn.com:expedient:openflow+switch:044:d0:02:6f:13:f3:b0:0+port:46"/>
        <port urn="urn:publicid:IDN+ofam1.site1.bbn.com:expedient:openflow+switch:044:d0:02:6f:13:f3:b0:0+port:47"/>
        <port urn="urn:publicid:IDN+ofam1.site1.bbn.com:expedient:openflow+switch:044:d0:02:6f:13:f3:b0:0+port:65534"/>
      </switch>
    </switches>
    <links/>
  </network>
</rspec>

The above provides the switch and the port URN information to be used in making the OF flowspace reservation. The above results will give you some insight into what is available, but it is recommended that you coordinate with the site contact to ensure RSPEC accuracy for each of the OF Aggregate Managers.

Request Resources

The OF RSPECs are used to request resources at each site's OpenFlow Aggregate Manager. This will result in your resource request being imported into the Opt-In manager, where an Administrator must approve your request for resources. Currently requesting OF resources for the sites in the experiment does not require OF setup for the Network Core path; the default handling will allow OF traffic. This is expected to change.

The OF RSPEC defines a flowspace for each OF rule for your traffic sliver. Following are example OF RSPECs that could be used to reserve the flowspaces needed for each of the generic 3 node scenario in this page. The scenario uses 3 OF Aggregate Managers (one per site) and one OF Controller at Site 1 for all sites. The example RSPECs are for each of the 3 OF AM and assume that the flowspace is based on traffic type and port (TCP port 9080 and 9082).

RSPEC Example for Site 1 OpenFlow Aggregate Manager

<resv_rspec type="openflow">
  <user affiliation="GPO" email="help@geni-net" firstname="GPO" lastname="Ops" password="xxxxxxx"/>
  <project description="Project description" name=" Project name"/>
  <slice controller_url="tcp:controller.site1.com:9933" description="description" name="name"/>
<flowspace>
    <switch urn="urn:publicid:IDN+ofam1.site1.com:expedient:openflow+switch:044:d0:02:6f:13:f3:b0:0"/>
    <tp_dst from="9080" to="9082"/>
  </flowspace>
  <flowspace>
    <switch urn="urn:publicid:IDN+ofam1.site1.com:expedient:openflow+switch:044:d0:02:6f:13:f3:b0:0"/>
    <tp_src from="9080" to="9082"/>
  </flowspace>
</resv_rspec>

RSPEC Example for Site 2 OpenFlow Aggregate Manager

<resv_rspec type="openflow">
  <user affiliation="GPO" email="help@geni-net" firstname="GPO" lastname="Ops" password="xxxxxxx"/>
  <project description="Project description" name=" Project name"/>
  <slice controller_url="tcp:controller.site1.com:9933" description="description" name="name"/>
<flowspace>
    <switch urn="urn:publicid:IDN+ofam2.site2.com:expedient:openflow+switch:00:00:00:13:65:f4:21:4f"/>
    <tp_dst from="9080" to="9082"/>
  </flowspace>
  <flowspace>
    <switch urn="urn:publicid:IDN+ofam2.site2.com:expedient:openflow+switch:00:00:00:13:65:f4:21:4f"/>
    <tp_src from="9080" to="9082"/>
  </flowspace>
</resv_rspec>

RSPEC Example for Site 3 OpenFlow Aggregate Manager

<resv_rspec type="openflow">
  <user affiliation="GPO" email="help@geni-net" firstname="GPO" lastname="Ops" password="xxxxxxx"/>
  <project description="Project description" name=" Project name"/>
  <slice controller_url="tcp:controller.site1.com:9933" description="description" name="name"/>
<flowspace>
    <switch urn="urn:publicid:IDN+ofam3.site3.com:expedient:openflow+switch:00:00:00:21:6f:b8:f3:d0"/>
    <tp_dst from="9080" to="9082"/>
  </flowspace>
  <flowspace>
    <switch urn="urn:publicid:IDN+ofam3.site3.com:expedient:openflow+switch:00:00:00:21:6f:b8:f3:d0"/>
    <tp_src from="9080" to="9082"/>
  </flowspace>
</resv_rspec>

Create Slice and Request Resources

Using the RSPEC that defines the required OF flowspace, you can now request OF resources with the Omni tools. First create a slice using your GPO Clearing House credentials as defined in the omni_config, note that the slice name should be meaningful to you:

$ ./src/omni.py createslice ln_OF_slice
INFO:omni:Loading config file omni_config
INFO:omni:Using control framework pgeni
Created slice with Name ln_OF_slice, URN urn:publicid:IDN+pgeni.gpolab.bbn.com+slice+ln_OF_slice

Then create a sliver for each resource aggregate. In this example there are 3 OF aggregates (one per site) and 3 compute resource aggregates (1 PG & 2 MyPLC), which maps to creating 6 slivers, and the following commands are executed:

 $ ./src/omni.py -n -a https://ofam1.site1.com:1443/openflow/gapi/ createsliver ln_OF_slice OF-site1.txt.rspec
 $ ./src/omni.py -n -a https://ofam2.site2.com:1443/openflow/gapi/ createsliver ln_OF_slice OF-site2.rspec
 $ ./src/omni.py -n -a https://ofam3.site3.com:1443/openflow/gapi/ createsliver ln_OF_slice OF-site3.rspec
 $ ./src/omni.py -n -a https://www.emulab.net/protogeni/xmlrpc/am createsliver ln_OF_slice emulab-site2.rspec
 $ ./src/omni.py -n -a http://myplc.site1.com:12346 createsliver ln_OF_slice myplc-site1.rspec
 $ ./src/omni.py -n -a http://myplc.site3.com:12346 createsliver ln_OF_slice myplc-site3.rspec

Note: Examples that detail rspec creation for the PG and MyPLC resource aggregates can be found in the other non-OF experiment example.

Opt-in Manager Administrative Approval

The OF Aggregate Administrator has to allow traffic from various nodes to be routed as decided by your OpenFlow controller. In this case, you are asking the administrator to route traffic on the PG and PL nodes you have just reserved. So you will need to give the site OF Aggregate Administrator:

  • your name
  • slice name and clearinghouse
  • PI name
  • duration of your experiment
  • IP address and names of the nodes whose traffic you need opted in (see the result of listresource and/or sliverstatus)
  • your flowspace request in plain text - what were you looking for

The OF Aggregate Administrator that opts-in your flows is responsible for resolving any conflicts between the traffic flows that you are requesting and the traffic flows requested by other experiments. If your flows are too generic (ex. all port 80 traffic) then they may overlap with other experiments; the administrator will have control over whether the conflict is resolved in your favor or someone else's.

Once the OF Aggregate Administrator has opted-in your traffic, you may start using the OF Resources.

Run Experiment

Once your flowspace has been opted in you should be able to exchange traffic over the approved flows between the hosts that have been allocated to your experiment. Simply SSH into one of the hosts and ping any of the other hosts to verify connectivity. If you have connectivity between the allocated hosts, you may start your experiment, if you do not have connectivity, contact the GPO at help@geni.net

Remember to check the expiration time for the flowspace and for each aggregate with the Omni sliverstatus and to renewslice to expand the duration of the resource allocation to match your experiment needs. For an example on how to check sliverstatus and renewslice see the checking status section of the other non-OF experiment.

Release Resources

When the experiment is completed you should release the resources by deleting the resource sliver for each the Resource Aggregates used in the Experiment. In the example experiment used in this page, the following commands should be issued to release resources:

 $ ./src/omni.py -n -a https://ofam1.site1.com:1443/openflow/gapi/ deletesliver ln_OF_slice 
 $ ./src/omni.py -n -a https://ofam2.site2.com:1443/openflow/gapi/ deletesliver ln_OF_slice 
 $ ./src/omni.py -n -a https://ofam3.site3.com:1443/openflow/gapi/ deletesliver ln_OF_slice 
 $ ./src/omni.py -n -a https://www.emulab.net/protogeni/xmlrpc/am deletesliver ln_OF_slice 
 $ ./src/omni.py -n -a http://myplc.site1.com:12346 deletesliver ln_OF_slice 
 $ ./src/omni.py -n -a http://myplc.site3.com:12346 deletesliver ln_OF_slice 

Email us with any questions and feedback on this page!

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