Loop with SDN controller

[Pradeep_30]

Hello Experts,

How to make HP SDN Controller to use spanning tree protocol ? I read somewhere it to support it.

I tried to create sample topology with two switch in mesh network using mininet. When I tried to ping the VMWare started to use maximum CPU and the packets were always dropping.

Is there something specific needs to be done to achieve spanning tree with mesh network ?

Thanks in advance.

Pradeep

[JulioCorrea · Accepted solution]

Hi,

Are you using the controller 2.2.5?

If so, check if the Hybrid mode is enabled (it is usually enabled by default). 

In this state the controller relies on the controlled switches to resolve loops, and determines forwarding paths by using
traditional networking mechanisms (such as STP, OSPF).

Follow these steps to change the configuration:

1. Start the web interface on the controller.
2. Click on the Configurations tab.
3. Select the com.hp.sdn.ctl.of.impl.ControllerManager component.
4. Click on the Modify key.
5. Select the hybrid mode Value field and set it to "false"

Restart the controller and mininet.

[sdnindia]

Hello Pradeep,

Did you try to modify the configuration of Controller as mentioned in earlier post?

Please let us know if you got your problem solved or still you are facing some issue.

Incase you are still facing the issue , please share the controller logs/config details.

Thanks,

HP SDN Team

[Pradeep_30]

Julio,

Thank you for the helping me out. Those were exact steps which helped.

SDN Team,

Could you please help me in understanding why this step is required from controller prespective?

Thanks in advance

Pradeep

[Pradeep_30]

FYI.

Attached is the basic loop topology script used.

[sdnindia]

Hello Pradeep,

As per the HP_VAN_SDN_Controller_2.2_Administrator_Guide.pdf [page 75]-

The hybrid mode setting determines which packet-forwarding decisions will be made by controlled OpenFlow switches and which of these decisions will be made by the controller itself.

• If hybrid mode is enabled (the default setting), the controller delegates normal packet forwarding to the controlled switches, but overrides these switches for non-standard packet-forwarding

decisions required by installed applications for specific packet types. In this state the controller relies on the controlled switches to resolve loops, and determines forwarding paths by using traditional networking mechanisms (such as STP, OSPF).

• If hybrid mode is disabled, the controller makes the forwarding decisions for all packets in the OpenFlow-controlled network. In this state, the controller resolves network loops and determines forwarding paths.

Thanks,

HP SDN Team