[Bridge] Re :Re: Re :Re: Bridging LACP (802.3ad) frames not working

Jean-Michel Hautbois jhautbois at gmail.com
Wed Jan 13 01:26:54 PST 2010


2010/1/12 richardvoigt at gmail.com <richardvoigt at gmail.com>:
> On Tue, Jan 12, 2010 at 4:04 PM, Ross Vandegrift <ross at kallisti.us> wrote:
>> On Tue, Jan 12, 2010 at 09:40:30PM +0000, jhautbois at gmail.com wrote:
>>> This is exactly the problem.
>>> But, sounds like it is not possible... ?
>>
>> You could run a custom version of the bridge driver to enable bridging
>> of frames sent to the bridge-management MAC addresses.  Some folks
>> have talked about doing similar things to enable bridging of STP.
>>
>> Doing that with STP makes a bit more sense to me (since there are
>> valid networks that could be constructed that way).  But you'll be
>> breaking a pretty fundamental assumption of LACP....
>
> LACP is between peers, not to the nearest connected device (generally
> an ethernet cable).  As long as the intermediate link acts just like a
> wire and passes everything, LACP shouldn't care.  And there are some
> reasonable cases to want a Linux box to look like a piece of cable
> (e.g. wiretap, timed lockdown, satellite network simulator which
> inserts delay and errors, etc.) to the surrounding network.  Of
> course, whether seeing just one link out of an aggregation bundle is
> useful is debatable, but Linux ought to be able to support it.  I've
> been bitten before by adding a new switch into an STP setup and having
> it eat STP packets even though STP processing was disabled.  So count
> me as another vote for (at least the possibility of) layer 1-esque
> transparent bridging.

I think it would be interesting to have the ability to activate this
functionality.
AFAIK, this could be done in the br_handle_frame function, testing the
skb->protocol and comparing it with ETH_P_SLOW. This could be
conditionned by a flag, and this flag would be unabled by default.

Why is this a problem ?
If you tell this is not good, unless you know what you are doing,
where is the problem ?
This is a user problem, it is a functionality. If you misuse it, this
is not a kernel problem...

Best Regards,
JM


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