[ovs-dev] I think I found a bug

Derek Cormier derek.cormier at lab.ntt.co.jp
Tue Feb 22 07:33:55 UTC 2011


Thanks, I'll give that a read.

What do you think about identical flows with no wildcards but different 
priorities? I notice that open vswitch just sets the priority to 65535 
for exact flows. Should identical flows with different priorities also 
be allowed?

- Derek

On 02/22/2011 04:20 PM, Justin Pettit wrote:
> Yes, I was using some poetic license in saying that we lost; that flag was put in there as a sort of compromise for those of us not in favor of always enforcing that behavior.  If you're really interested, you can see some of the discussion starting here:
>
> 	https://mailman.stanford.edu/pipermail/openflow-dev/2008-April/000133.html
>
> --Justin
>
>
> On Feb 21, 2011, at 11:03 PM, Romain Lenglet wrote:
>
>> Hi,
>> I thought that accepting (or not) overlapping flows at the same priority was up to the controller?
>> Isn't that what the check_overlap flag is for in flow_mod messages?
>> -- 
>> Romain Lenglet
>>
>> On Tuesday, February 22, 2011 at 16:00, Justin Pettit wrote:
>>
>>> I would expect so. One use that people have brought in the past is that you could setup backup routes at a lower priority, with the higher ones timing out or being forcibly removed. I don't know how useful that actually is, but people have discussed doingg that before with OpenFlow.
>>>
>>> In general, Ben and I have been fairly negative in the OpenFlow discussions about putting in "sanity" checks at flow insertion time due to the complexity and expense of enforcing them. There was quite a lengthy discussion a year or so back about preventing users from being able to put overlapping flows at the same priority--we lost that one. :-)
>>>
>>> --Justin
>>>
>>>
>>> On Feb 21, 2011, at 10:52 PM, Derek Cormier wrote:
>>>
>>>> I expected that since the flow with the lower priority will never be matched over the higher one, it has no purpose and would not be added.
>>>>
>>>> Hmm, on second glance, the protocol says that if you add an identical flow that also has the same priority then the flow will just be replaced.
>>>> But, I don't think it says anything about this case. Sorry, I should have confirmed that before posting.
>>>>
>>>> That said, do you think these identical flows should be allowed?
>>>>
>>>> - Derek
>>>>
>>>> On 02/22/2011 03:43 PM, Justin Pettit wrote:
>>>>> I would expect that you can. What did you expect? What did you see? It's not clear from this output if it's working or not, since neither couunter shows a value. Are you running traffic?
>>>>>
>>>>> --Justin
>>>>>
>>>>>
>>>>> On Feb 21, 2011, at 10:35 PM, Derek Cormier wrote:
>>>>>
>>>>>> Should I be able to add two identical wildcarded flows with different priorities? I was talking with KK and he thinks this might be a bug. I always assumed this was just the way it works. Here is my ovs-ofctl flow dump:
>>>>>>
>>>>>> cookie=0x0, duration=94.608s, table_id=0, n_packets=0, n_bytes=0, priority=5,dl_type=0x0005 actions=drop
>>>>>> cookie=0x0, duration=98.109s, table_id=0, n_packets=0, n_bytes=0, priority=1,dl_type=0x0005 actions=drop
>>>>>>
>>>>>> Thanks,
>>>>>> - Derek
>>>>>>
>>>>>> _______________________________________________
>>>>>> dev mailing list
>>>>>> dev at openvswitch.org
>>>>>> http://openvswitch.org/mailman/listinfo/dev_openvswitch.org
>>>
>>> _______________________________________________
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>
>





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