RE: [lwip-users] TCP not sending initial ACK

[JM]

It only took me 3 -4 weeks to figure this out, but if you're on a hub, try a switch.  Apparently if your micro is in full duplex mode, a hub is a no-go.  I'm using the LM driver and it works great for receiving lots of data, anyway. 

Take a look at the "Identification" field in the IP header for all packets going one direction.  They should be sequential and incrementing.  If there's a gap in the sequence, that means Wireshark isn't displaying a packet that was sent, either because your hardware or OS discarded it.

I haven't tried half-duplex yet with the hub again.  I'm assuming this would also fix your problem.

--- On Wed, 8/26/09, Chuck Kuecker <address@hidden> wrote:

From: Chuck Kuecker <address@hidden>
Subject: RE: [lwip-users] TCP not sending initial ACK
To: "Mailing list for lwIP users" <address@hidden>
Date: Wednesday, August 26, 2009, 11:54 AM

No, the LWIP timers are called from the main timer tick, and there are
no other threads. This is how LWIP is set up for the Luminary driver
library I am using, and it has always worked before.

Wireshark shows no defective packets.

Chuck

-----Original Message-----
From: lwip-users-bounces+ckuecker=address@hidden
[mailto:lwip-users-bounces+ckuecker=address@hidden] On
Behalf Of address@hidden
Sent: Wednesday, August 26, 2009 10:34 AM
To: Mailing list for lwIP users
Subject: Re: [lwip-users] TCP not sending initial ACK

Chuck Kuecker wrote:
>
> I've tried changing the frequency of LWIP interrupt handler calls,
> both greatly slowing and speeding them up, with no apparent change in
> behavior.
>
What exactly do you mean with "interrupt handler calls"? The timers?
They should *not* be called from an interrupt level: the core code of
lwIP may only be accessed from one context at a time!

If you obeyed this rule and still have problems, have a look at
wireshark packet traces and see if it reports errors in a packet. Also,
have a look at the stats (turn them on in lwipopts.h if not already
done) and find out whether there are packets dropped.

Simon


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