[ovs-dev] WDP problem

Stefan Kobza skobza at juniper.net
Thu Oct 21 18:05:22 UTC 2010


First of all, thanks for such quick response!
See inline.

>On Thu, Oct 21, 2010 at 10:27:23AM +0100, Stefan Kobza wrote:
>> we ran into problems using the WDP branch from Openvswitch. First of all, we
>> need to know whether we are using the correct approach. Basically we created
>> xfif_class and registered it as only base_xfif_classes entry. We saw that
>> registered xfif_classes get picked up by wdp, and are being called when
>> needed (port_add, port_del, etc..).

>If you are implementing an xfif, then I am surprised that you are using
>the wdp branch at all.

What datapath should we then use? Should we implement our own wdp ?
We implemented xfif because we saw that it is called from wdp-xflow, and that the wdp-xflow handles all sorts of things on top of it. We thought that the wdp-xflow processes the flow_mod message, and eventually should call the xfifs's flow_put.

>> Our problem is that when flow_mod message is received on OVS part, it
>> doesn't call our xfif's flow_put. 

>I would only expect it to do so for exact-match flows.  Because OVS has
>a "tunnel ID" field in its flow match, which is always wildcarded unless
>a special OVS extension is enabled, it is not possible to set up
>exact-match flows using standard OpenFlow 1.0, and so you won't see such
>behavior with an OpenFlow 1.0 controller.

We use openflow 1.1.0pre2, does that change anything?

>For a flow that has wildcards, the flow is kept in the classifier until
>a packet arrives that matches it, at which time the exact-match flow
>corresponding to that packet is set up and the xfif's flow_put is called
>to add it.

The exact-match flow is set up to match the same packets; that means that the wildcarded fields are at first filled with values from the received packet, and then sent to xfif?

Thanks in advance,
Stefan




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