USB Serial Modem LCP after ~60 minutes


#1

I have an Alcatel Onetouch X500 USB serial modem connected to a RasPi 2 Model B running Ubuntu 16.04.2 LTS.

I use wvdial for connecting to the network (config follows):

Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
Modem Type = USB Modem
Phone = 99**1#
ISDN = 0
Username = " "
Password = " "
Init1 = ATZ
Init3 = AT+CGDCONT=1,“IP”,"hologram"
Modem = /dev/ttyUSB3
Baud = 9600
Stupid Mode = on
Auto DNS = 0
Dial Command = ATDT
Carrier Check = yes
Auto Reconnect = on```

I have been using this as an emergency ssh portal in the event of my primary system going down for a few weeks without issue. Recently the modem has been disconnecting from the T-Mobile tower regularly at ~60 minutes. I wrote a service to check for a connection and reconnect if it’s disconnected. Below is a section of the logs:

``Apr 12 20:14:30 raspi pppd[22801]: Connect time 60.1 minutes.
Apr 12 20:15:01 raspi monusbmodem[22774]: WAN Link Up
Apr 12 21:14:42 raspi pppd[23878]: Connect time 60.1 minutes.
Apr 12 21:15:18 raspi monusbmodem[22774]: WAN Link Up
Apr 12 22:14:55 raspi pppd[24973]: Connect time 60.1 minutes.
Apr 12 22:15:35 raspi monusbmodem[22774]: WAN Link Up
Apr 12 23:15:09 raspi pppd[26031]: Connect time 60.1 minutes.
Apr 12 23:15:52 raspi monusbmodem[22774]: WAN Link Up
Apr 13 00:15:21 raspi pppd[27118]: Connect time 60.1 minutes.
Apr 13 00:16:09 raspi monusbmodem[22774]: WAN Link Up
Apr 13 01:15:34 raspi pppd[28470]: Connect time 60.1 minutes.
Apr 13 01:16:26 raspi monusbmodem[22774]: WAN Link Up
Apr 13 02:15:47 raspi pppd[29560]: Connect time 60.1 minutes.
Apr 13 02:16:43 raspi monusbmodem[22774]: WAN Link Up
Apr 13 03:16:00 raspi pppd[30939]: Connect time 60.1 minutes.
Apr 13 03:17:00 raspi monusbmodem[22774]: WAN Link Up
Apr 13 04:16:12 raspi pppd[32024]: Connect time 60.1 minutes.
Apr 13 04:17:16 raspi monusbmodem[22774]: WAN Link Up
Apr 13 05:16:27 raspi pppd[655]: Connect time 60.1 minutes.
Apr 13 05:17:33 raspi monusbmodem[22774]: WAN Link Up
Apr 13 06:16:40 raspi pppd[1804]: Connect time 60.1 minutes.
Apr 13 06:17:50 raspi monusbmodem[22774]: WAN Link Up
Apr 13 07:16:55 raspi pppd[3168]: Connect time 60.1 minutes.
Apr 13 07:17:17 raspi monusbmodem[22774]: WAN Link Up
Apr 13 08:17:07 raspi pppd[4345]: Connect time 60.1 minutes.
Apr 13 08:17:34 raspi monusbmodem[22774]: WAN Link Up
Apr 13 09:17:22 raspi pppd[5489]: Connect time 60.1 minutes.
Apr 13 09:17:51 raspi monusbmodem[22774]: WAN Link Up
Apr 13 10:17:35 raspi pppd[6578]: Connect time 60.1 minutes.
Apr 13 10:18:08 raspi monusbmodem[22774]: WAN Link Up


Apr 12 16:42:48 raspi pppd[17965]: rcvd [LCP TermReq id=0x37]
Apr 12 16:42:48 raspi pppd[17965]: LCP terminated by peer
Apr 12 16:42:48 raspi pppd[17965]: Connect time 60.0 minutes.
``

It’s a little less regular in older logs but it’s always right around 60 minutes.

Is this something I need to configure on my side?
Is it an idle timeout from hologram or T-Mobile?

I’m not sure if this is expected behavior as it wasn’t happening when I started a few weeks ago but is now.

Thanks!


#2

Nothing wrong on your side. After 60 minutes of inactivity, the connection will be closed. This is on the carrier side.


#3

So my service is probably the best approach then? That works for me, and good to know, thanks!