u3g Sierra Wireless LTE device disconnects ppp after 2-3MB of outgoing traffic

[mike tancsa]

On 12/11/2019 2:11 AM, Adrian Gschwend wrote:
> On 03.12.19 22:50, Mike Tancsa wrote:
>
>> I dont use mpd, only the built in ppp.  Can you try it with the built in
>> ppp ? Looking at your log snippets
> I meanwhile had issues again and I'm now running on ppp. It behaves ok
> until it doesn't, so somehow the issues are back here as well. I am
> currently logging quite a lot so let's see what I figure out.


Do you have LQR/ech enabled ?  Here is the ppp.conf section I use

pppgprs:
 set device /dev/cuaU0.3
 set server /var/run/gprs-internet "" 0177
 set speed 921600
 set timeout 0
 set authname wapuser1
 set authkey wap
 set dial "ABORT BUSY TIMEOUT 2 \
        \"\" \
        AT OK-AT-OK \
        AT+CFUN=1 OK-AT-OK \
        AT+CMEE=2 OK-AT-OK \
        AT+CSQ OK \
        AT+CGDCONT=2,\\\"IP\\\",\\\"ltemobile.apn\\\" OK \
        AT+CGACT? OK-AT-OK \
        AT+CGATT? OK \
        AT+CGCLASS? OK \
        AT+COPS? OK \
        AT!GSTATUS? OK \
        AT&v OK \
        ATD*99# CONNECT"
 set crtscts on
 #set mtu maximum 296
 #set mru maximum 296
 disable vjcomp
 disable acfcomp
 disable deflate
 disable deflate24
 disable pred1
 disable protocomp
 disable mppe
 disable ipv6cp
 set lqrperiod 10
 enable lqr
 enable echo
 disable dns
 set ifaddr 10.1.0.2/0 10.1.0.1/0 255.255.255.255 0.0.0.0
 add default HISADDR          # See ppp.link*


>
> ppp seems nice, I especially like pppctl to see status of the line.
>
> What I can't seem to figure out is how to send AT commands like
> AT!GSTATUS? on "demand" to the modem with pppctl, any ideas of how this
> would look like?

Depending on your modem, some Sierra's dont allow the GSTATUS command
from the management port, just signal info. Eg. port /dev/cuaU0.3 is my
data port to make my ppp connection on, I can connect to cuaU1.4 to ask
some basic info like signal.  Sierra should have a pretty good AT
command set manual free to download so you can see what is exactly
available.

% cu -l /dev/cuaU1.4
Connected
Sierra Wireless, Incorporated
MC7700
APP1

OK
+CSQ: 21,99
OK


for whatever reason, ate1 is not respected, so my commands dont show.
the above is the output of entering ati and at+csq

 set lqrperiod 10
 enable lqr
 enable echo

should allow ppp to reconnect should ppp disconnect.

you should in your logs see

 ppp[3416]: tun10: LCP: deflink: SendEchoRequest(80560) state = Opened
 ppp[3416]: tun10: LCP: deflink: RecvEchoReply(176) state = Opened

    ---Mike