Re: [lwip-users] Broadcast packets breaking my network traffic

[Caglar Akyuz]

Kieran Mansley wrote:
> On Thu, 2007-07-19 at 18:11 +0300, Caglar Akyuz wrote:
>> Kieran Mansley wrote:
>>> On Thu, 2007-07-19 at 15:35 +0100, Kieran Mansley wrote:
>>>> Can you get a small ethereal capture to illustrate this?  The fact that
>>>> the hub makes a difference is interesting.  I wonder if it is a problem
>>>> with the boards seeing packets from one of the other boards.  Does it
>>>> happen in response to all broadcast ARP packets, or only some?  Does it
>>>> happen in response to other broadcast packets?  
>>> Is there any traffic (other than broadcast packets and TCP ACKs) going
>>> back from the PC to the devices?  If not, it could be just that the
>>> board receiving data is causing them problems (rather than it being
>>> broadcast packets in particular).  You could try sending a UDP stream at
>>> the board (which should just drop the packets if there is nothing
>>> listening to receive them) and see what that does.
>>>
>> No there isn't no other traffic other than packets and ACKS. Do you
>> think pinging may cause the same effect because I'm pinging the devices
>> while packets are flying. Some times pinging was ok, sometimes it
>> crushed the boards.
> 
> If pinging kills the board I suggest there is something seriously wrong.
> Not sure where though I would guess it might be something to do with
> protection of the core stack.  Perhaps you have an rx packet and a tx
> packet being processed at the same time and this causes corruption.  How
> do you synchronise processing of RX and TX in your port?

I rely on sys_arch_protect and sys_arch_unprotect. They're
disabling/enabling interrupts at the cpu level. I also tried adding some
other protection. For instance, I disabled passing broadcast packets
from my mac driver to lwIP while I'm transmitting any packets.(disabled
before calling tcp_ouput, enabled after tcp_sent callback)

One thing I suspect is that there is something wrong with physical
layer, or at least there are more than one problems and one of them is
related to phy. For that reason, I disabled full duplex mode and I'm
using half-duplex mode at the both sides, I think full-duplex mode
doesn't help me much while using a hub.(I'm not %100 sure...)

I'm trying to catch an appropriate packet capture, I'm sure you will say
some thing better than me after seeing it.

Thanks for your concern.
Caglar

> 
> Kieran
> 
> 
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