patchlwIP - A Lightweight TCP/IP stack - Patches: patch #8312, Congestion problem

 
 

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patch #8312: Congestion problem

Submitter:  Marek NOVAK <ok2nmz>
Submitted:  Wed 12 Feb 2014 12:25:32 PM UTC
   
 
Category:  TCP Priority:  5 - Normal
Status:  Invalid Privacy:  Public
Assigned to:  None Open/Closed:  Closed
Planned Release:  None

Mon 19 Jan 2015 04:56:19 PM UTC, comment #2: 

Closing as invalid after nearly a year without more input.

Most definitively, this is a configuration issue, especially because you say you are using pools for all memory allocations.

(You did not say which kind of pools, maybe your pool allocation scheme leads to not having any more memory to receive ACK packets.)

Simon Goldschmidt <goldsimon>
Group administrator
Thu 20 Feb 2014 08:21:45 PM UTC, comment #1: 

This is a bug report together with a suggested workaround, not at all a patch!
Patches are ready-to-use source code changes that we should commit.

I'd very much welcome it if you could close this one and add it again as a bug.

Thanks.

Simon Goldschmidt <goldsimon>
Group administrator
Wed 12 Feb 2014 12:25:32 PM UTC, original submission:  

Hello everybody,
 First, I'd like to say thank you to every single developper who has worked on LwIP. It is such a nice piece of code!

Now for what I found out.
I am using LPC1768 as my platform and I wrote a simple telnet implementation using RAW api. My system is quite short on memory (2x32kB) and as I fear memory fragmentation, I am using pools for all dynamically allocated/deallocated memory.
If I try to send a lot of querries to my telnet, the TCP connections hangs with output queue full and keeps retransmitting everything and for me, it seems like LwIP starts ignoring any ACK sent to these retransmissions. Some time afterwards, LwIP resets the TCP connection, since the max number of retransmissions is reached.
However, when I changed this from:
#define TCP_OVERSIZE 0
#define LWIP_NETIF_TX_SINGLE_PBUF  0

to

#define TCP_OVERSIZE TCP_MSS
#define LWIP_NETIF_TX_SINGLE_PBUF   1

The problems disappeared.

I am using LwIP head version.

I hope it helps somebody...

Regards from the Czech republic, BUT FEEC university in Brno,
 Marek Novak

Marek NOVAK <ok2nmz>

 

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    Date Changed by Updated Field Previous Value => Replaced by
    2015-01-19 goldsimon StatusNone Invalid
        Open/ClosedOpen Closed

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