[lwip-users] RE: lwip-users Digest, Vol 21, Issue 12

[Sami OULED ALI]

Registration confirm

-----Original Message-----
From: address@hidden
[mailto:address@hidden On Behalf Of
address@hidden
Sent: Thursday, May 26, 2005 5:59 PM
To: address@hidden
Subject: lwip-users Digest, Vol 21, Issue 12


Send lwip-users mailing list submissions to
        address@hidden

To subscribe or unsubscribe via the World Wide Web, visit
        http://lists.nongnu.org/mailman/listinfo/lwip-users
or, via email, send a message with subject or body 'help' to
        address@hidden

You can reach the person managing the list at
        address@hidden

When replying, please edit your Subject line so it is more specific than
"Re: Contents of lwip-users digest..."


Today's Topics:

   1. TCP issue... (Eric Knudstrup)
   2. Re: TCP issue... (Kieran Mansley)
   3. Re: TCP issue... (address@hidden)


----------------------------------------------------------------------

Message: 1
Date: Wed, 25 May 2005 15:51:07 -0700
From: Eric Knudstrup <address@hidden>
Subject: [lwip-users] TCP issue...
To: address@hidden
Message-ID: <address@hidden>
Content-Type: text/plain; charset="us-ascii"

I'm using lwIP 1.1 with all of the latest updates and I'm having some
trouble. Against a Linux 2.4 server, data reception is disgustingly slow.
Basically what happens is that when lwIP sends one of its duplicate acks the
server will then wait 200ms and resend the packet that was acked? An
ethereal trace is attached.  Note packet 12, which is acked by packet 13.
Then it is acked again by packet 15.  The linux box waits 200ms before
*retransmitting* packet 12?

Eric

-- 
In Heaven:
The French cook, The British are the police, and the Germans are the
mechanics. In Hell: The Germans are the police, the British are the cooks,
and the French are the mechanics.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: tcpfunny
Type: application/octet-stream
Size: 6492 bytes
Desc: not available
Url :
http://lists.gnu.org/pipermail/lwip-users/attachments/20050525/058f7d91/tcpf
unny.obj

------------------------------

Message: 2
Date: Thu, 26 May 2005 09:36:59 +0100
From: Kieran Mansley <address@hidden>
Subject: Re: [lwip-users] TCP issue...
To: Mailing list for lwIP users <address@hidden>
Message-ID: <address@hidden>
Content-Type: text/plain

On Wed, 2005-05-25 at 15:51 -0700, Eric Knudstrup wrote:
> I'm using lwIP 1.1 with all of the latest updates and I'm having some 
> trouble. Against a Linux 2.4 server, data reception is disgustingly 
> slow. Basically what happens is that when lwIP sends one of its 
> duplicate acks the server will then wait 200ms and resend the packet 
> that was acked? An ethereal trace is attached.  Note packet 12, which 
> is acked by packet 13.

No, packet 13 ACKs packet 10.  

> Then it is acked again by packet 15.  The linux box waits 200ms before 
> *retransmitting* packet 12?

The sequence looks fine to me.  There is some problem with the packet 12
when it is received or lost, and so this is not ACKed.  Instead, packet 10
is ACKed twice (packets 13 and 15) as should be done, and if another packet
had been received in the stream packet 10 would have been ACKed a third
time.  However, as the window is small there aren't enough packets in the
stream to do this and so the fast retransmit (which needs 3 duplicate ACKs)
can't kick in.  

After a 200ms timeout, the other end retransmits that oldest unacknowledged
packet, which is 12 (the one that had a problem, we presume).  The receiver
gets this and then ACKs all the outstanding data (packets 12 and 14) in
packet 17.

The only question is why packet 12 was rejected the first time.  I presume
this dump was captured at the linux side, so it's possible the packet could
have been lost or corrupted in transit, but given the low level of traffic
(and assuming there wasn't other traffic on your
network) that seems unlikely.

Kieran





------------------------------

Message: 3
Date: Thu, 26 May 2005 11:38:11 +0200 (CEST)
From: address@hidden
Subject: Re: [lwip-users] TCP issue...
To: "Mailing list for lwIP users" <address@hidden>
Message-ID:
        <address@hidden>
Content-Type: text/plain;charset=iso-8859-2

Hi
I have had similar problem, solution for my implementation lwip was to
increase polling frequency of ethernet thread.


> I'm using lwIP 1.1 with all of the latest updates and I'm having some 
> trouble. Against a Linux 2.4 server, data reception is disgustingly 
> slow. Basically what happens is that when lwIP sends one of its 
> duplicate acks the server will then wait 200ms and resend the packet 
> that was acked? An ethereal trace is attached.  Note packet 12, which 
> is acked by packet 13.  Then it is acked again by packet 15.  The 
> linux box waits 200ms before *retransmitting* packet 12?
>
> Eric
>
> --
> In Heaven:
> The French cook, The British are the police, and the Germans are the 
> mechanics. In Hell:
> The Germans are the police, the British are the cooks, and the French
> are the mechanics.
>
> _______________________________________________
> lwip-users mailing list
> address@hidden 
> http://lists.nongnu.org/mailman/listinfo/lwip-users






------------------------------

_______________________________________________
lwip-users mailing list
address@hidden http://lists.nongnu.org/mailman/listinfo/lwip-users

End of lwip-users Digest, Vol 21, Issue 12
******************************************