[ovs-discuss] Flow removed message bug

[Derek Cormier]

On page 14 of the spec, it says that if _STRICT is used, all fields, 
including the wildcards and priority, are strictly matched against the 
entry, and only an identical flow is modified or removed.

- Derek

On 02/22/2011 11:04 AM, kk yap wrote:
> Hi Derek,
>
> Actually priority for exact match does not matter.  So, there cannot
> be two different exact match flow entries that only differ by
> priority up till at least OpenFlow 1.0.  That's the case I was thinking about.
>
> Regards
> KK
>
> On 21 February 2011 17:54, Derek Cormier<derek.cormier at lab.ntt.co.jp>  wrote:
>> Hi KK,
>>
>> Thanks for posting this to the openflow-spec board. I do think the priority
>> should be maintained since two identical flow matches can exist with
>> different priorities. If one of them is removed, it could be useful to know
>> which one. To identify a flow uniquely, I believe you need the ofp_match&
>> priority (unless a cookie is used).
>>
>> - Derek
>>
>> On 02/22/2011 03:27 AM, kk yap wrote:
>>> Hi,
>>>
>>> I believe maintaining the wildcards would be enough.  To me, the
>>> following two matches are the same:
>>>
>>> Wildcards = ALL - DL_TYPE, DL_TYPE = 5, IP_SRC = 100...
>>> Wildcards = ALL - DL_TYPE, DL_TYPE = 5, IP_SRC = 0...
>>>
>>> I believe Ben and Justin is saying that it is reasonable to maintain
>>> the wildcard field.  Seems like we have a working solution?
>>>
>>> I will post this on the openflow-spec list for the words to be cleared
>>> up.  The priority field worries me a little more, such I think exact
>>> match is normalized to priority 65535?  Should that be maintained in
>>> flow_removed?  I wonder.
>>>
>>> Regards
>>> KK
>>>
>>> On 21 February 2011 09:30, Ben Pfaff<blp at nicira.com>    wrote:
>>>> On Sun, Feb 20, 2011 at 11:36 PM, Derek Cormier
>>>> <derek.cormier at lab.ntt.co.jp>    wrote:
>>>>> I see what you mean and I agree that a switch shouldn't store
>>>>> unnecessary
>>>>> information. But is it really a burden in this case? The wildcards are
>>>>> stored in a single 32-bit integer, so no extra space is needed.
>>>> The data structure that OVS uses for classification requires that
>>>> wildcarded fields
>>>> be zeroed for efficiency reasons.  In other words, storing the wildcards
>>>> isn't a
>>>> big deal, but storing nonzero values of wildcarded fields would require
>>>> extra
>>>> memory.  So I'd rather not do it, although certainly it's not a huge
>>>> deal if in the
>>>> OVS has to.
>>>>
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>>>>
>>
>