Re: [L2switch-dev] How to compute the routing path between two hosts in OpenDayLight?

Y. Richard Yang

On Fri, Aug 7, 2015 at 1:30 PM, Evan Zeller <evanrzeller@...> wrote:
You may be interested in , as for other protocols there is no such module that I know of. It seems to me that this baseline traditional networking functionality is one of the first things newcomers to ODL look for, but don't find as actual resources seem focused in other areas. Food for thought...

Is this something to engage the ODL TSC to look into?

As far as the path functionality in l2switch I'm not sure about it. Maybe Amit can comment on it.

On Fri, Aug 7, 2015 at 8:24 AM, Junzhuo Wang <wangjunzhuo200@...> wrote:
A further question. Is there a layer 3 routing module could make OpenFlow switcher acts like a traditional router?


Hi Evan,

It great to have your reply! I’ve seen that the method “addBidirectionalMacToMacFlows” calls “addMacToMacFlow” twice. Based on the code, I assume in this implementation, the STP eliminate loops so all packets can be forwarded to all switchers. So only two flow entries could build a path between two MAC addresses.

But in my test, the MAC to MAC flow only be built when two hosts connected to the same switcher. This phenomenon really confuses me. I’m looking forward to your reply.


The Minimum Spanning Tree is calculated to prevent loops in the network, those links that receive STP blocking status won't have flows written on them. in l2switch-main may have what you're looking for, it can create mac to mac flows, I'm not sure how robust the functionality is at the moment. 

On Thu, Aug 6, 2015 at 9:14 AM, Junzhuo Wang <wangjunzhuo200@...> wrote:
Hi André,

Thanks a lot for your reply! I’ve read the code from ( The "getPath" method doesn’t exist anymore as you said. Also I did some tests and I found that the packets not always go through the shortest path. So I believe STP may be used as the current routing algorithm. If so, I can calculate the path by my self although it’s not a clean implementation. Let’s say what the code’s author says.


Hi Junzhuo.
The code is here
but I don't know if the service is working because of
But I've send this email to the code's author to see what he says about it.
Best regards,

On 06-08-2015 07:43, Junzhuo Wang wrote:
Hi all,

I’m a member from ODL/ALTO. I’m trying to find a API to compute the routing path between two hosts. So I read the code from openflowplugin, controller. It seems openflowplugin just set the flow table to switchers. And controller seems no longer handle the routing calculation now
 (org.opendaylight.controller.sal.routing doesn’t exist now).

Finally I found this page( saids that the l2switch now provide routing service. Which module should I use and how to get the route between two hosts by existing APIs?


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