[ovs-discuss] OpenVSwitch looped topology without bonds/STP

[Colton Powell]

Hi Ray,

Thanks for your response. 

We wish to write flows to OpenVSwitches in any given topology to redirect traffic in the network. In our case, we wish to redirect some traffic between machines if certain conditions are met (IE: there is sufficient bandwidth available on the links leading to that machine, etc), and we want this scheme to work for any given type of topology, including those with loops.

We currently do this using OpenDaylight: It will discover the topology of the network, and then provides a way for us to view the topology (for example, we can issue a RESTCONF query to view it). Afterwards, we take this information, and create various flows to redirect traffic depending on network (and other) conditions.

Now the redirecting traffic part appears to be pretty straightforward: Simply match by src/dst IP address, and then output on some port for all switches along a given path.

The difficult part for us, however, is actually finding the paths to redirect on. Because we are currently using STP in our looped topology, OpenDaylight cannot find all links/paths in the network. Only links on the Spanning Tree are found (similarly, any link that would create a cycle/loop is not found).

So, from the controller-side of things, we do not have visibility of all links in the network. As a result, we cannot optimally distribute traffic throughout the network, due to the fact that we do not have a complete view of all links in the network.

Therefore, we were either hoping to a) find a solution without STP or b) Use STP, but modify our OVS configuration, with the ultimate goal of achieving visibility of all links in the network.

I hope that clarifies my intent a bit. Please let me know if I can provide any other information, and thanks again for your help.

Colton