4G Modem won't stay alive

RouterOS General
1

I have recently figured out how to connect a Pantech UML290 to the Verizon LTE network here. My problem is that every so often the connection drops and I’m stuck here in my log:

00:47:30 system,info,account user admin logged in from 192.168.88.100 via ssh
01:21:27 async,ppp,info ppp-out1: terminating...
01:21:27 async,ppp,info ppp-out1: disconnected
01:21:37 async,ppp,info ppp-out1: initializing...
01:21:37 async,ppp,info ppp-out1: reseting link...
01:21:38 async,ppp,info ppp-out1: terminating... - modem hunged up
01:21:38 async,ppp,info ppp-out1: disconnected
01:21:48 async,ppp,info ppp-out1: initializing...
01:21:48 async,ppp,info ppp-out1: reseting link...
01:21:49 async,ppp,info ppp-out1: initializing modem...
01:21:49 async,ppp,info ppp-out1: dialing out...
01:21:52 async,ppp,info ppp-out1: authenticated
01:21:52 async,ppp,info ppp-out1: connected
01:21:52 system,info dns changed
01:22:24 async,ppp,info ppp-out1: terminating...
01:22:24 async,ppp,info ppp-out1: disconnected
01:22:24 async,ppp,info ppp-out1: initializing...
01:22:24 async,ppp,info ppp-out1: reseting link...

I have the keep-alive setting enabled, but it doesn’t seem to work:

[admin@MikroTik] /interface ppp-client> print
Flags: X - disabled, R - running
 0    name="ppp-out1" max-mtu=1500 max-mru=1500 mrru=disabled port=usb4
      data-channel=0 info-channel=0 pin="" user="7048137024@vzw4g.com"
      password="vzw" profile=default phone="*99***3#" dial-command="ATDT"
      modem-init="ATZ;ATQ0 v1 E1 S0=0 &C1 &D2 +FCLASS=0" null-modem=no
      dial-on-demand=no add-default-route=yes use-peer-dns=yes
      keepalive-timeout=30 allow=pap,chap,mschap1,mschap2
[admin@MikroTik] /interface ppp-client>

Does anyone have any ideas on how I can fix this?

Thanks,

Charlie

2

Just to follow up, I had the Mikrotik connect to Verizon last night and ping google. It start out great but when I woke up I found the pings had 94% packet loss. So it got disconnected early and never attempted a reconnect. The first thing I did was disable the ppp-client and re-enable it. Then it was connected again in 5 seconds. Here’s a log:

no route to host
                                                        no route to host
                                                        no route to host
                                                        no route to host
    sent=25240 received=1413 packet-loss=94% min-rtt=77ms avg-rtt=105ms
   max-rtt=177ms
HOST                                    SIZE  TTL TIME  STATUS
                                                        no route to host
                                                        no route to host
                                                        no route to host
    sent=25243 received=1413 packet-loss=94% min-rtt=77ms avg-rtt=105ms
   max-rtt=177ms

[admin@MikroTik] > /interface ppp-client
[admin@MikroTik] /interface ppp-client> print
Flags: X - disabled, R - running
 0    name="ppp-out1" max-mtu=1500 max-mru=1500 mrru=disabled port=usb4
      data-channel=0 info-channel=0 pin="" user="7048137024@vzw4g.com"
      password="vzw" profile=default phone="*99***3#" dial-command="ATDT"
      modem-init="ATZ;ATQ0 v1 E1 S0=0 &C1 &D2 +FCLASS=0" null-modem=no
      dial-on-demand=no add-default-route=yes use-peer-dns=yes
      keepalive-timeout=30 allow=pap,chap,mschap1,mschap2
[admin@MikroTik] /interface ppp-client> disable 0
[admin@MikroTik] /interface ppp-client> enable 0
[admin@MikroTik] /interface ppp-client> print
Flags: X - disabled, R - running
 0    name="ppp-out1" max-mtu=1500 max-mru=1500 mrru=disabled port=usb4
      data-channel=0 info-channel=0 pin="" user="7048137024@vzw4g.com"
      password="vzw" profile=default phone="*99***3#" dial-command="ATDT"
      modem-init="ATZ;ATQ0 v1 E1 S0=0 &C1 &D2 +FCLASS=0" null-modem=no
      dial-on-demand=no add-default-route=yes use-peer-dns=yes
      keepalive-timeout=30 allow=pap,chap,mschap1,mschap2
[admin@MikroTik] /interface ppp-client> print
Flags: X - disabled, R - running
 0  R name="ppp-out1" max-mtu=1500 max-mru=1500 mrru=disabled port=usb4
      data-channel=0 info-channel=0 pin="" user="7048137024@vzw4g.com"
      password="vzw" profile=default phone="*99***3#" dial-command="ATDT"
      modem-init="ATZ;ATQ0 v1 E1 S0=0 &C1 &D2 +FCLASS=0" null-modem=no
      dial-on-demand=no add-default-route=yes use-peer-dns=yes
      keepalive-timeout=30 allow=pap,chap,mschap1,mschap2
[admin@MikroTik] /interface ppp-client>

Does anyone have any tips? Admittedly I’m in a weak connection zone for 4G, but that’s why this is a good place to test the keep-alive functionality.

Is it a modem string that I need to change? Where do I even find the modem commands for the Pantech UML290?

Thanks for any help.

Charlie

3

Charlie, you are not alone in having issues with the 4G modems on Verizon. I have been testing the UML290 and continue to have very strange connectivity issues. In a Windows XP computer I can get the modem to come up fine using the latest drivers and version of VZ Access Manager (VZAM_7.6.3.5_2642k_PantechLTE). On Windows 7 64 it does not work at all. On MT, I can get the modem to occasionally connect, but then it will drop and never reconnect.

It appears that there are some proprietary commands that configure the modem through the Windows drivers. These are not AT commands that I can see. I have tried all manner of combinations of AT commands issues through serial-terminal. Many come up with errors.

If anyone can get this modem to behave stably, I would love to know how.

Attached is some documentation on AT commands for Qualcomm MDM9600 which is what is inside the UML290.
2130616 Extended AT Commands v5.pdf (1.12 MB)
2130617 Supported AT Commands v5.pdf (437 KB)

4

Anyone having any better luck with getting any 4G devices in the US to stay connected to carrier? Been working with a Sierra MC7750 embedded module in RB411U but MT does not seen to support LTE on this device. PPP seems erratic. Got this back from support regarding the MC7750 quote “if your sierra card uses PPP mode it would work as currently we do not support QMI
mode for this modem. Yes, that card will fit in the RB411U with SIM slot.”




@Doghead…believe I saw a post that you were working on some of these issues…any luck?