Re: [Madwifi-users] [SPAM] Madwifi v0.9.4 latest release: Frames transmitted out of sequence

[Ashwin <ash...@gm...>]

Hi Mohan,

As it seems, the issue is more with the setup that you have. Maybe you 
can try tweaking (increasing) buffers settings under sysctl ?

Could also be an issue with the "wired" interface with low buffers (in 
the hardware itself). Use a very high quality ethernet card.

with Regards,
ASHWIN


On 12/16/2010 01:21 PM, Mohan R wrote:
> Hi Dennis&  Wayne,
>
> Thanks for your response.
>
> In my application I receive UDP/IPV4 packets from a wired interface. I have
> no control on this protocol.
>
> My application has a peek of the data in frame, collects some statistics and
> just forwards the frame over the wireless interface using dev_queue_xmit.
> One of the nodes is configured as AP&  the other as Station. There is a
> sequence number associated with the payload. That is how I know that the
> packets are out of order when I receive them at the far end.
>
> I have Linux version 2.6.18 running on MIPS platform with AR5414A chipset
> based mini-PCI.
>
> When I started work on this application, I had examined the packet sequence
> from the wired i/f. They seemed to be in order. I will verify this once
> again.
>
> My question now is are there any circumstances under which madwifi or
> dev_queue_xmit can reorder packets ?
>
> Regards
>
> R.Mohan
>
>
>
> -----Original Message-----
> From: Wayne Johnson [mailto:wa...@zk...]
> Sent: Wednesday, December 15, 2010 11:52 PM
> To: Dennis Borgmann; MOHAN.R.
> Cc: mad...@li...
> Subject: RE: [Madwifi-users] [SPAM] Madwifi v0.9.4 latest release: Frames
> transmitted out of sequence
>
>
>
>> -----Original Message-----
>> From: Dennis Borgmann [mailto:den...@go...]
>> Sent: Wednesday, December 15, 2010 5:39 AM
>> To: MOHAN.R.
>> Cc: mad...@li...
>> Subject: Re: [Madwifi-users] [SPAM] Madwifi v0.9.4 latest release:
>> Frames transmitted out of sequence
>>
>> Hi Mohan!
>>
>> Maybe this is not an issue of madwifi, but an issue of you IP
> protocol?
>> Are you using UDP? If so, try TCP since it guarantees the sequence of
>> packet transmission.
>>
>> HTH,
>> Dennis Borgmann
>
> I don't think your statement is necessarily correct. With TCP, data
> leaving the transport layer and entering the application layer is
> guaranteed to be in order but packets can still arrive on the network
> layer out of order.
>
> It has been some time since I have done a lot of TCP/IP work but it is
> my understanding the out of order typically not a problem unless there
> is routing going on.
>
>>
>> MOHAN.R. schrieb:
>>> Dear All,
>>>
>>>
>>>
>>> Occasionally I find that frames are being transmitted out of
> sequence
>> by
>>> both AP as well as Station.
>>>
>>>
>>>
>>> This is not desirable for my application.
>>>
>>>
>>>
>>> Can anyone tell me why this happens and how to ensure that frames
> are
>>> always sent in sequence.
>>>
>
> Without making quite a few assumptions it's not possible to even
> understand what you are asking here. A lot more detail is required. How
> are you sending the packets? How are you determining they are out of
> order? What hardware and software are you using on both ends? What are
> you trying to do?
>
> I don't want you to take this the wrong way, I am still trying to be
> helpful. Even though engineers are known for their literary skills ;-),
> answering questions still takes quite a bit of effort. I have found that
> most people try hard to be helpful when they can see that you are trying
> hard to figure it out. Most likely you are working very hard to figure
> out your problem but your email does not convey that and will probably
> be ignored by the people who (unlike me) can be most helpful.
>
> Wayne
>
>
>
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