Re: [lwip-users] PPP: IPCP bad fcs issue

[Axel Lin]

2018-08-16 3:40 GMT+08:00 Patrick Klos <address@hidden>:
> On 8/15/2018 11:25 AM, Axel Lin wrote:
>
> Hi list,
>
> I'm testing a LTE module with lwIP and found always got bad fcs as below.
> I dump the received data below:
> Is there anything wrong in the received data?
>
> sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2
> 0.0.0.0>]␍␊
> pppos_write[0]: len=26␍␊
> pppos_input[0]: got 17 bytes␍␊
> 7e ff 3 80 21 1 1 16 3 6 81 6 83 6 6e db 7e ␍␍␊
> pppos_input[0]: Dropping bad fcs 0x4114 proto=0x8021␍␊
>
>
> That doesn't look like a good PPP packet.

Hi Patrick and Sylvain,
Thanks for your valuable comments.
I re-check my code and found I disable LCP magic number negotiation
due to hit issue without checking the root cause.
So the first error should be "Serial line is looped back".
I will check with module vendor.

Thanks,
Axel