Toby-L201 connect failure Ubuntu 18.04 Modem Manager 1.10.6 Linux Kernel Version 4.20.7

[Cale Collins]

Hello Ulrich,

I tried to apply this patch, it seems nearly all of what's contained is
present in 1.8.  I had some issues getting it to apply, would it be
possible for you recreate this patch for me (perhaps with only the
necessary elements)?

Ideally I would like to be using 1.12.x.  I'm still having all sorts of
trouble with TOBY L201, and Sara R410 when using Modem Manger.

Thanks,



*Cale CollinsField Applications EngineerGateworks Corporation*
(805)781-2000 x37
3026 S. Higuera, San Luis Obispo, CA 93401
www.gateworks.com



On Tue, Dec 10, 2019 at 3:08 AM Ulrich Mohr <u.mohr at semex-engcon.com> wrote:

> Hey,
>
> I tried to reconstruct what I did to work around the problem.
>
> 1. When dial in takes place, I check upfront whether there is an active
> context that matches the requested one. If there is one, I use it, and
> skip activating another one. This prevents creating a secondary context
> when the default context is already active (which might fail as shown by
> the recent bug report -- some providers do not allow a secondary
> context, e.g. vodafone DE).
>
> 2. I seen cases where the default context does not match the APN at all.
> In this case, the first step would not detect the active context as the
> right one and create a second one. In case I've seen that, the creation
> of the second context succeeded, but the context is not used by the
> modem (because ublox does not set routes to the secondary context).
> Therefore, I also adapt the routes in the modem to match the new context.
>
> I think that what I did is far from perfects, because theses two
> measures will fail when only one context is allowed AND the default
> context does not match the default one (although I never seen this so
> far). Also, it is not the recommended way from the ublox manuals, since
> they request to use set default eps bearer in case the network provided
> one does not work.
>
> I attach the patch I use at the moment (based on version 1.7.999.)
> Please be aware that this also includes (inactive) code from other
> things I tried, e.g. setting the default bearer as requested by the
> ublox manuals.
>
> That's unfortunately all I can provide at the moment, sorry for that.
>
> Best regards,
>
> Uli
>
> Am 10.12.2019 um 10:23 schrieb Aleksander Morgado:
> > On Fri, Dec 6, 2019 at 9:11 AM Ulrich Mohr <u.mohr at semex-engcon.com>
> wrote:
> >> Hi,
> >>
> >> I am not sure, but I think that this is a problem with the UBlox modems
> I was facing before with a TOBY 210.
> >>
> >> The problem is that the modem does an automatic registration on the LTE
> network using its default APN (that it gets from the network, when I
> understand right). That is what you see (m2m.com.attz.mnc170.mcc310.gprs)
> as context 4:  (which is the default LTE bearer on TOBY). Unfortunately,
> that does not match the one your have given manually, so ModemManager tries
> to build up a connection using the secondary context with the APN settings
> you have given -- which fails, because the service provider does not allow
> a secondary connection while the first one is active.
> >>
> >> What I am not completely clear about is, under which circumstances you
> get such a long default APN name (not matching the 'official' ones) from
> the network.
> >>
> > The "long" name you get is when the bearer is already connected to
> > that APN, so the name includes the MCCMNC of the operator.
> > ModemManager already does a "loose" matching of the APNs and they
> > should already match that one in context 4 if available:
> >
> https://gitlab.freedesktop.org/mobile-broadband/ModemManager/blob/master/src/mm-modem-helpers.c#L1506
> >
> > As you said, MM should have attempted to use context #4 instead of #1
> > as #4 was already connected. The problem is that the logic looking for
> > which context to use stops as soon as it finds a matching one, and in
> > this case it found #1 before #4. We could extend the logic to "prefer"
> > an APN that is reported with MCCMNC if there are more than one
> > matching, and I believe that should work.
> >
> >> @Aleksander: See
> https://lists.freedesktop.org/archives/modemmanager-devel/2018-August/006633.html
> >>
> >> I heavily change the ublox plugin to work around that -- unfortunately
> I never found the time to bring it to a deliverable state, and at the
> moment, I can't even remember what exactly I did. But I can provide the
> sources if needed....
> > Yes, please, can you do that?
> >
> >
> --
> Best regards / Mit freundlichen Grüßen / Salutations distinguées
>
> Ulrich Mohr
>
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> email:  u.mohr at semex-engcon.com
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