Re: [lwip-users] Duplicated ACK and retransmitted packets

[Lou Cypher]

> This looks like a driver problem, but you could check a few things to
> verify.  It's not clear from your description which end in the trace is
> lwIP and which is the PC.  It seems like whenever one end sends more
> than one packet in a row to the other the second one is dropped.  This
> should be easy to track down as it is very repeatable from the look of
> it.
> 
> 1) If lwIP is the receiver of the lost packets:

Please excuse me if that wasn't clear: yes, this is the case.
(The IP numbers in trace are .130/PC/FTP server and .131/lwIP/FTP client)

> If you enable some of the logging in lwIP to print out a few details of
> each packet when it is received (don't enable lots of stuff as otherwise
> the messages will swamp things) like the TCP sequence number, or IP ID
> field, that would show whether the packets are getting as far as lwIP or
> being lost in the driver somewhere.

I did some more checking at the Ethernet MAC level, though everything seems 
proper.
Now I will enable some debug message and try to understand what happens of the
packet after it's been fetched from the Ethernet MAC. It's just lengthy and
tedious, since I have to skip lots of other packets on that interface; another
issue could be given by the messages on serial port: if too many, they could
slow down the lwIP system, changing and/or masking the problem.
Let's see, will post some more info if I run into (new) troubles (...)

Thanks,

~ Lou

____________________________________________________________
GET FREE 5GB EMAIL - Check out spam free email with many cool features!
Visit http://www.inbox.com/email to find out more!