[Bridge] Tap and Bridge problem

[Bridge] Tap and Bridge problem

[Lambert Laurent]

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Hi,

I'm currently trying to use bridge and tap for my work. In my setup I use
two programs communicating though tap interface. I connect the two tap
interface with a bridge.

Now comes the problem, currently only broadcast or multicast frames goes
through the bridge. Every unicast frame get drop (or stuck) between the
bridge and the input of the tap device. I traced this with tcpdump. The
message is seen on the sender tap if, on the bridge and disapears on the
receiver tap if.
Also the frame seems to be well formated (tcpdump identifies it properly).

to instanciate a bridge i use :
brctl addbr br0
brctl addif br0 tap0
brctl addif br0 tap1

i then ifconfig up the bridge and the two tap interface.

I also noticed in linux log that the bridge puts tap port in disabled
state.

Did anyone this behavior in the past time ?

Thank you.

-- 
Lambert Laurent

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Re: [Bridge] Tap and Bridge problem

[Marek Kierdelewicz]

> Hi,

Hi,

>I'm currently trying to use bridge and tap for my work. In my setup I
>use two programs communicating though tap interface. I connect the two
>tap interface with a bridge.
>...
>Now comes the problem, currently only broadcast or multicast frames
>goes through the bridge. Every unicast frame get drop (or stuck)
>between the
>Did anyone this behavior in the past time ?

Yes. Try using veth pair interfaces:
ip link add name veth1 type veth peer name veth2
You'll get veth1 and veth2 pair that act as a "wormhole". Now add veth1
to the bridge and use veth2 with your program in the way you used tap.

If you need second pair just repeat procedure with different interface
names.

Best regards,
Marek Kierdelewicz

Re: [Bridge] Tap and Bridge problem

[Lambert Laurent]

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Hi,

Thank you for your answer. From what i understand two tap interface can't
speak together though a bridge. so the idea is to have two veth pair
between each tap and the bridge. I should get the following topology:

Tap0 == <Veth10> == <Veth00> == bridge == <Veth01> == <Veth11> == Tap1

Now i'm not sure to understand how to connect the tap device to the Veth.
Can you give me a hint on that part ?

Thank you


2013/7/7 Marek Kierdelewicz <marek@piasta.pl>

> > Hi,
>
> Hi,
>
> >I'm currently trying to use bridge and tap for my work. In my setup I
> >use two programs communicating though tap interface. I connect the two
> >tap interface with a bridge.
> >...
> >Now comes the problem, currently only broadcast or multicast frames
> >goes through the bridge. Every unicast frame get drop (or stuck)
> >between the
> >Did anyone this behavior in the past time ?
>
> Yes. Try using veth pair interfaces:
> ip link add name veth1 type veth peer name veth2
> You'll get veth1 and veth2 pair that act as a "wormhole". Now add veth1
> to the bridge and use veth2 with your program in the way you used tap.
>
> If you need second pair just repeat procedure with different interface
> names.
>
> Best regards,
> Marek Kierdelewicz
>



-- 
Lambert Laurent

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