topic Re: HP VAN Controller and barrier request/reply messages in Software Defined Networking

HP VAN Controller and barrier request/reply messages

JoonKim — Thu, 27 Feb 2014 01:45:50 GMT

Hi,

I have a question about HP VAN controller's FlowMod sending function.

Barrier message is used to ensure OpenFlow message ordering sent from the controller. From the OF v1.3 spec:

When the controller wants to ensure message dependencies have been met or wants to receive notifications
for completed operations, it may use an OFPT_BARRIER_REQUEST message. This message has no body. Upon
receipt, the switch must finish processing all previously-received messages, including sending corresponding
reply or error messages, before executing any messages beyond the Barrier Request. When such processing
is complete, the switch must send an OFPT_BARRIER_REPLY message with the xid of the original request.

When using the ControllerService interface's sendFlowMod() method, the controller seems to send a barrier request automatically, right after the flow-mod message goes out. Is there a way to disable that? It would be nicer to manually send barrier requests only at the necessary points. However, I cannot find an API-supported way to do that.

Do you have any suggestions that might help?

Thanks,

Joon

Re: HP VAN Controller and barrier request/reply messages

JoonKim — Wed, 05 Mar 2014 04:12:11 GMT

Solved.

1.Go to https://<controller_ip>:8443/sdn/ui

2. From the left menu, click "Configurations".

3. From the component list, click "com.hp.sdn.ctl.of.impl.ControllerManager", then click "Modify" on the top.

4. Make "confirm.flowmod" value to "false".

Then sendFlowMod() method will not automatically send out a barrier request after its original flow-mod message. You can create your own barrier request message if you want.

-Joon

Re: HP VAN Controller and barrier request/reply messages

ShaunWackerly — Wed, 05 Mar 2014 20:52:05 GMT

Hi JoonKim,

Thanks for posting this solution for the current release. We are planning to add the ability to confirm flow-mods into our next release of the SDN controller, so you'll have the ability to control this behavior for each specific flow-mod, rather than globally as it is now.

Re: HP VAN Controller and barrier request/reply messages

sdnindia — Fri, 07 Mar 2014 10:44:44 GMT

Hello JoonKim,

We are glad that your problem is solved.
Please do let us know if you need further assistance.

Please feel free to reply incase you have more questions around the same topic or open a new thread if new topic.

Thanks
HP SDN Team