Subject: Re: [PATCH net-next 0/4] Allow bridge to function in non-promisc mode

From: Vlad Yasevich <[email-masked]>
Date: Wed, 13 Mar 2013 13:04:51 -0400

On 03/13/2013 12:09 PM, Stephen Hemminger wrote:
> On Wed, 13 Mar 2013 11:45:40 -0400
> Vlad Yasevich <[email-masked]> wrote:
>
>> On 03/13/2013 11:39 AM, Stephen Hemminger wrote:
>>> On Wed, 13 Mar 2013 08:12:29 -0400
>>> Vlad Yasevich <[email-masked]> wrote:
>>>
>>>> On 03/13/2013 02:22 AM, "Oleg A. Arkhangelsky" wrote:
>>>>>
>>>>>
>>>>> 13.03.2013, 05:45, "Vlad Yasevich" <[email-masked]>:
>>>>>
>>>>>> The series adds an ability for the bridge to function in non-promiscuous mode.
>>>>>
>>>>> What is the practical applications for such setup? In other words,
>>>>> in which cases I would want to put bridge into non-promiscuous
>>>>> mode and specify some uplink ports?
>>>>>
>>>>
>>>> On of the applications would be when bridge is an edge device servicing
>>>> a VM deployment.  Each of the VMs knows the mac address that the guest
>>>> has and may program that mac onto the uplinks.
>>>
>>> Why wouldn't that environment just use macvlan?
>>> Is it because changing libvirt is harder than changing the kernel?
>>>
>>
>> No, because macvlan has a drawback that it doesn't easily let guests
>> talk to the host.  Bridge is still most commonly used for just that reason.
>>
>> -vlad
>
> Maybe fixing that with a flag to macvlan would be easier?
>

Not really.  macvlan to physical device could be made simple enough.
However, physical to macvlan is non-trivial at all.

We get around this right now by crating a macvlan on the host and
have macvlan to macvlan communication essentially turning it into
bridge.  But that doesn't work in all scenarios either.

-vlad