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

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

Mohan R

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.

 

 

Thanks

 

R.Mohan

 


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

Dennis Borgmann
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

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.
>
>  
>
>  
>
> Thanks
>
>  
>
> R.Mohan
>
>  
>
>
>  
> ------------------------------------------------------------------------
>
> ------------------------------------------------------------------------------
> Lotusphere 2011
> Register now for Lotusphere 2011 and learn how
> to connect the dots, take your collaborative environment
> to the next level, and enter the era of Social Business.
> http://p.sf.net/sfu/lotusphere-d2d
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>
> _______________________________________________
> Madwifi-users mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/madwifi-users
>  


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

Wayne Johnson
In reply to this post by Mohan R


> -----Original Message-----
> From: Dennis Borgmann [mailto:[hidden email]]
> Sent: Wednesday, December 15, 2010 5:39 AM
> To: MOHAN.R.
> Cc: [hidden email]
> 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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Re: [SPAM] Madwifi v0.9.4 latest release: Frames transmitted out of sequence

Mohan R
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:[hidden email]]
Sent: Wednesday, December 15, 2010 11:52 PM
To: Dennis Borgmann; MOHAN.R.
Cc: [hidden email]
Subject: RE: [Madwifi-users] [SPAM] Madwifi v0.9.4 latest release: Frames
transmitted out of sequence



> -----Original Message-----
> From: Dennis Borgmann [mailto:[hidden email]]
> Sent: Wednesday, December 15, 2010 5:39 AM
> To: MOHAN.R.
> Cc: [hidden email]
> 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



The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments contained in it.


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

Dennis Borgmann
Mohan,

I am not that much into the driver specifics of madwifi, but I am very
interested in the solution to your problem. So keep us up to date ;-)

I wonder, what other people might answer on the list anyway...

Dennis

Mohan R schrieb:

> 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:[hidden email]]
> Sent: Wednesday, December 15, 2010 11:52 PM
> To: Dennis Borgmann; MOHAN.R.
> Cc: [hidden email]
> Subject: RE: [Madwifi-users] [SPAM] Madwifi v0.9.4 latest release: Frames
> transmitted out of sequence
>
>
>
>  
>> -----Original Message-----
>> From: Dennis Borgmann [mailto:[hidden email]]
>> Sent: Wednesday, December 15, 2010 5:39 AM
>> To: MOHAN.R.
>> Cc: [hidden email]
>> 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
>
>
>
> The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments contained in it.
>
>  


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

Ashwin-5-3
In reply to this post by Mohan R
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:[hidden email]]
> Sent: Wednesday, December 15, 2010 11:52 PM
> To: Dennis Borgmann; MOHAN.R.
> Cc: [hidden email]
> Subject: RE: [Madwifi-users] [SPAM] Madwifi v0.9.4 latest release: Frames
> transmitted out of sequence
>
>
>
>> -----Original Message-----
>> From: Dennis Borgmann [mailto:[hidden email]]
>> Sent: Wednesday, December 15, 2010 5:39 AM
>> To: MOHAN.R.
>> Cc: [hidden email]
>> 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
>
>
>
> The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments contained in it.
>
>
> ------------------------------------------------------------------------------
> Lotusphere 2011
> Register now for Lotusphere 2011 and learn how
> to connect the dots, take your collaborative environment
> to the next level, and enter the era of Social Business.
> http://p.sf.net/sfu/lotusphere-d2d
> _______________________________________________
> Madwifi-users mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/madwifi-users
>


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

Mohan R
Hi Ashwin,

I have verified that I am not dropping any packets.
It is just that occasionally packets are reordered.

Statistics on the wired or the wireless interface do not report any lost or
dropped packets

R.Mohan

-----Original Message-----
From: Ashwin [mailto:[hidden email]]
Sent: Thursday, December 16, 2010 4:55 PM
To: [hidden email]
Subject: Re: [Madwifi-users] [SPAM] Madwifi v0.9.4 latest release: Frames
transmitted out of sequence

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:[hidden email]]
> Sent: Wednesday, December 15, 2010 11:52 PM
> To: Dennis Borgmann; MOHAN.R.
> Cc: [hidden email]
> Subject: RE: [Madwifi-users] [SPAM] Madwifi v0.9.4 latest release: Frames
> transmitted out of sequence
>
>
>
>> -----Original Message-----
>> From: Dennis Borgmann [mailto:[hidden email]]
>> Sent: Wednesday, December 15, 2010 5:39 AM
>> To: MOHAN.R.
>> Cc: [hidden email]
>> 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
>
>
>
> The information contained in this electronic message and any attachments
to this message are intended for the exclusive use of the addressee(s) and
may contain proprietary, confidential or privileged information. If you are
not the intended recipient, you should not disseminate, distribute or copy
this e-mail. Please notify the sender immediately and destroy all copies of
this message and any attachments contained in it.
>
>
>
----------------------------------------------------------------------------
--

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> Register now for Lotusphere 2011 and learn how
> to connect the dots, take your collaborative environment
> to the next level, and enter the era of Social Business.
> http://p.sf.net/sfu/lotusphere-d2d
> _______________________________________________
> Madwifi-users mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/madwifi-users
>


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The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments contained in it.


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

Brian Prodoehl
On Thu, Dec 16, 2010 at 8:24 AM, Mohan R <[hidden email]> wrote:
Hi Ashwin,

I have verified that I am not dropping any packets.
It is just that occasionally packets are reordered.

Statistics on the wired or the wireless interface do not report any lost or
dropped packets

R.Mohan

-----Original Message-----
From: Ashwin [mailto:[hidden email]]
Sent: Thursday, December 16, 2010 4:55 PM
To: [hidden email]
Subject: Re: [Madwifi-users] [SPAM] Madwifi v0.9.4 latest release: Frames
transmitted out of sequence

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:[hidden email]]
> Sent: Wednesday, December 15, 2010 11:52 PM
> To: Dennis Borgmann; MOHAN.R.
> Cc: [hidden email]
> Subject: RE: [Madwifi-users] [SPAM] Madwifi v0.9.4 latest release: Frames
> transmitted out of sequence
>
>
>
>> -----Original Message-----
>> From: Dennis Borgmann [mailto:[hidden email]]
>> Sent: Wednesday, December 15, 2010 5:39 AM
>> To: MOHAN.R.
>> Cc: [hidden email]
>> 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

Mohan,

Can you please test UDP performance of your system with iperf?  iperf -s -u -i 1 will launch a test server, and iperf -c <address of server> -b 2M -i 1 will launch a client sending a 2Mbps stream to the server (adjust throughput as you see fit).  The server will report statistics on dropped and out of order packets every second.  You can also adjust the packet size to more closely reflect what your application is doing.  I haven't seen more than the occasional out of order packet, and I'd like to see what a standard test tool reports.

Brian

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Re: [SPAM] Madwifi v0.9.4 latest release: Framestransmitted out of sequence

Wayne Johnson
In reply to this post by Ashwin-5-3


> -----Original Message-----
> From: Mohan R [mailto:[hidden email]]
> Sent: Thursday, December 16, 2010 7:36 AM
> To: 'Ashwin'; [hidden email]
> Subject: Re: [Madwifi-users] [SPAM] Madwifi v0.9.4 latest release:
> Framestransmitted out of sequence
>
> Hi Ashwin,
>
> I have verified that I am not dropping any packets.
> It is just that occasionally packets are reordered.
>
> Statistics on the wired or the wireless interface do not report any
> lost or
> dropped packets
>
> R.Mohan
>

UDP does not make any guarantees about what order packets will arrive.
If you are going to use UDP you *must* handle packets arriving out of
order. My understanding that this is not serious problem when both the
source and destination are on the same network; however, you still need
to handle it because UDP does not make any guarantees. You also must
build into your protocol the ability to handle missed packets because
UDP does not guarantee that packet will arrive. UPD *only* guarantees
that it will give its best effort to deliver a packet.

Wayne

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