Hi Carsten, If it comes to implementing the NCM protocol, it's nice to hear that you > will guide me :-)
Aleksander gave me some guidance for a similar situation and what you want to do here is going to be very similar to the 'mm-broadband-bearer-cinterion.c' & 'mm-broadband-bearer-huawei.c' files. Basically in the 'mm-broadband-modem..' you'll need to have a way to detect support for Telits's NCM Protocol, such as sending a test read cmd and checking for a certain response. If that cmd if supported you'll set a flag to use in the 'mm-broadband-bearer..' to setup the WWAN connection, or something like that. On Thu, Nov 8, 2018 at 9:29 AM Stelling2 Carsten < carsten.stelli...@goerlitz.com> wrote: > Hi Aleksander, > > Thank you for your fast reply, and explanation. > Meanwhile, I've updated MM to 1.8.2 within my Yocto-Project. > Also, thanks for your hint to AT#USBCFG=5 (yes, 5 or 3 should work). I'll > give it a try tomorrow. > > Regarding the NCM protocol, I followed the instructions in Telits's NCM > Protocol User Guide. > > AT+CGDCONT=4,"IP","APN" > AT#NCM=2,4,0,"User Name", "Password" > Then, I used the output of AT+CGCONTRDP=4, to configure the wwan0 > interface manually. It works. > > If it comes to implementing the NCM protocol, it's nice to hear that you > will guide me :-) > > Thanks, > > Carsten > > -----Ursprüngliche Nachricht----- > Von: Aleksander Morgado [mailto:aleksan...@aleksander.es] > Gesendet: Donnerstag, 8. November 2018 16:59 > An: Stelling2 Carsten; modemmanager-devel@lists.freedesktop.org > Betreff: Re: Telit LE910 V2, cdc_ncm and systemd > > Hey, > > > This is the first time I'm using ModemManager. > > The type of the modem is Telit LE910 V2 (product ID = 0036), providing > cdc_acm, and cdc_ncm ports. > > I'm working on an embedded system, running kernel version 4.9.26. > > The Init-system is systemd version 232. > > Actually I've installed MM version 1.6.4 (which comes with Yocto 2.3). > > > > That is an extremely old version, you should definitely try to update. But > anyway, for the specific issue you're seeing, it would probably be the > same, see below. > > > I can successfully establish a connection to the bearer. > > > > The command mmcli -b 0 outputs: > > > > -------------------------- > > Status | connected: 'yes' > > | suspended: 'no' > > | interface: 'ttyACM0' > > | IP timeout: '20' > > -------------------------- > > Properties | apn: '****' > > | roaming: 'allowed' > > | IP type: 'ipv4' > > | user: '****' > > | password: '****' > > | number: 'none' > > | user: '****' > > | Rm protocol: 'unknown' > > -------------------------- > > IPv4 configuration | method: 'ppp' > > | address: 'unknown' > > | prefix: '0' > > | gateway: 'unknown' > > | DNS: 'none' > > -------------------------- > > IPv6 configuration | method: 'unknown' > > -------------------------- > > Stats | duration: '300' > > | Bytes received: 'N/A' > > | Bytes transmitted: 'N/A' > > > > If I start my ppp-on script immediately (within the same second) after > issuing the command mmcli -m 0 -c -b 0, and receiving the message > 'successfully connected the bearer', the PPP connection can be established, > and the configured interface ppp0 comes up. The IP connection works fine. > >> But, when waiting several seconds (5 seconds or more) between mmcli -m > 0 -c -b 0 ('successfully connected the bearer') and starting the ppp-on > script, the PPP connect attempt always fails. Within /var/log/syslog, I can > see the following messages: > > pppd[493]: pppd 2.4.7 started by root, uid 0 > > pppd[493]: using channel 1 > > pppd[493]: Using interface ppp0 > > pppd[493]: Connect: ppp0 <--> /dev/ttyACM0 > > pppd[493]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x081d45a2> > <pcomp> <acomp> > > pppd[493]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x081d45a2> > <pcomp> <acomp> > > pppd[493]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x081d45a2> > <pcomp> <acomp> > > pppd[493]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x081d45a2> > <pcomp> <acomp> > > pppd[493]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x081d45a2> > <pcomp> <acomp> > > pppd[493]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x081d45a2> > <pcomp> <acomp> > > pppd[493]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x081d45a2> > <pcomp> <acomp> > > pppd[493]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x081d45a2> > <pcomp> <acomp> > > pppd[493]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x081d45a2> > <pcomp> <acomp> > > pppd[493]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x081d45a2> > <pcomp> <acomp> > > pppd[493]: LCP timeout sending Config-Requests > > > > In this case, when opening /dev/ttyACM0 with minicom, I can send AT and > get back OK from the modem. That surprise me. I would expect that ttyACM0 > is a transparent channel for PPP, and not an AT interface, when > successfully connected to the bearer. At the same time, I can see MM > communicating with the modem via ttyACM3 (as expected). > > > > Maybe there's some max time to get PPP up in the tty before it goes back > to command mode? > > > I can't see any dependency to the output of mmcli -b 0 Status IP > timeout: '20'. Where is this timeout set? Is this the intended behavior of > MM or do I miss something? > > > > That value is just a "hint" for the upper layers (e.g. NetworkManager) > about the max time to wait for an IP addressing setup in the data port. In > reality that value is always 20s except for the very special case of > satellite comm modems (e.g. Iridium) where 20s for an IP establishment was > too optimistic... > > > Another question I have, is there a way to automatically configure the > wwan0 (NCM) interface directly, using only systemd mechanisms (no > NetworkManager involved)? Telit suggests to use the NCM protocol in > conjunction with LTE connections. Is PPP really a bottleneck for LTE > connections? > > > > PPP over the TTY is indeed a bottleneck if you want LTE throughput. This > modem is designed to be used with the NCM interface definitely. > > > I've tried > > [Match] > > Name=wwan0 > > > > [Network] > > DHCP=ipv4 > > > > but this does not work. Most probably, because the modem LE910 V2 does > not support DHCP (neither QMI or MBIM). ip shows the wwan0 interface, but > it is neither configured nor up. > > Doesn't have to do anything with QMI or MBIM really. This modem needs an > AT command to get the modem connected before anything can be sent via the > NCM interface. ModemManager currently doesn't support the AT+NCM > combination in Telit modems, but it's just a lack of implementation, no > other real reason. I actually think I have an old LE910 around somewhere > here... > > Speaking of which, I believe you can change the device to MBIM mode with > AT#USBCFG=5, have you tried that? > > > Does anybody have a working systemd configuration or an idea how to > achieve this (without NetworkManager)? > > > > Unless you can configure the modem to "transparently autoconnect" and act > as a router, then you cannot use the NCM interface directly, you need to > control the modem via AT commands to bring the connection up. > > > At least, I miss settings for the PDP context ID to use for a specific > bearer. With a Vodafone SIM, we have to use a specific PDP context ID to > access a private APN. Furthermore, the PDP context is different for 2G and > 4G. Is this an undocumented feature of MM? > > The missing AT commands to setup the connection via the NCM interface > (AT#NCM, AT+CGACT, AT+CGDATA...) would also allow you to configure exactly > which PDP contexts/EPS bearers to use. E.g you would do something like > "configure PDP context with cid N with the settings you want" and then > "connect cid N over the NCM interface", something in those lines. > > If you're interested in implementing the AT+NCM support let me know and I > can guide you a bit if needed. > > -- > Aleksander > https://aleksander.es > > > _______________________________________________ > ModemManager-devel mailing list > ModemManager-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/modemmanager-devel >
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