Re: [lwip-users] PPPoS : no response from modem after link established

[Sergey A. Borshch]

On 07.07.2018 23:41, Sylvain Rochet wrote:

> > The problem is identical to to described at
> > https://lists.gnu.org/archive/html/lwip-users/2017-10/msg00084.html
> > (but there was no solution proposed)
>
> I don't know how you managed to conclude that no solution was
> proposed... User had CHECKSUM disabled, see:
> https://lists.gnu.org/archive/html/lwip-users/2017-11/msg00072.html
Thank you very much for pointing this. I didn't understand how did I missed that 
answer. Yes, disabling hardware checksum calculation did the trick and now 
everything works ok.

 Can I suggest to add some flag into netif to enable/disable software checksum 
calculation? Using this flag can be selectable at compile time #if (PPP_SUPPORT 
!= 0) && (CHECKSUM_GEN_xxx == 0)
 add flag into netif, init it in ppp_create and use
#else
 use CHECKSUM_GEN_xxx
#endif

> >   - modem stops responding after status_cb:
> > connected. I checked twice with logic analyzer - there is to responses to
> > frames with proto=0x21. I tried two SIM cards from different mobile
> > providers (one requires authentication, the other not) with exactly same
> > result - I can get IP, DNS etc but no data exchange.
> >
> > What did I missed to do?
>
> Did you check that you are actually receiving IP packets on the remote
> side ?
I have no access to other side - I have no computers with real IP (I'm in third 
mobile operator local network).

> Sylvain

--
Regards,
  Sergey A. Borshch            mailto: address@hidden
    SB ELDI ltd. Riga, Latvia