Re: [lwip-users] Debug pppos packet loss issue

[Axel Lin]

2017-03-02 21:10 GMT+08:00 Sylvain Rochet <address@hidden>:
> Hi Axel,
>
> On Thu, Mar 02, 2017 at 08:55:15PM +0800, Axel Lin wrote:
>> Hi,
>> I'm using current lwIP master tree.
>>
>> I got my device connect to internet via 4G/LTE module now (by PPPoS).
>> However, I found sometimes download file size mismatch when
>> try to download some files (about 100KB) from http server.
>>
>> I tried enable PPP_DEBUG / PRINTPKT_SUPPORT / PPP_PROTOCOLNAME /
>> LWIP_STATS_DISPLAY, but I don't see any unusual things.
>>
>> The only strange thing is in download success case, the download speed
>> is fast. In download file mismatch (seems some packet lost) case, the
>> download speed is very low. Any hint to debug such issue?
>
> HTTP uses TCP so whatever happens you shouldn't have a size mismatch.
>
> As usual, for the must common lwIP misuse, if you are using an OS, you
> must not call RAW API outside the lwIP TCPIP thread and since you are
> using PPPoS you must use the thread-safe PPPoS input API (see PPP
> documentation).
Hi Sylvain,
Thanks for your comment.
I'm using netconn API and running with FreeRTOS.
I call pppos_input_tcpip() when received serial input.

BTW, I found the correct file and damaged file always has (TCP_MSS *
x)  file size mismatch.
In my case, TCP_MSS is 1152.

Thanks,
Axel