Reliable 3G connectivity


I just wanted to get some advice from fellow forum members. I’m trying to get a reliable 3G connection set up. I currently have a Mifi unit as well as an AR150. I have tried various dongles but I have had the most success with a ZTE MF823 in serial mode. Critical factors for me are:

  • Reliability
  • Remote access via port forwarding and a public IP
I have obtained special M2M sim cards which use a special APN that allows port forwarding and provides a public IP. I have 2 different SIM cards from 2 suppliers that operate on the same cellular network.

Here is what I have tried:

  • I confirmed that the MF823 dongles work with both sims by testing in a Windows computer before putting them in Serial mode
  • I have been unable to get either sim to work in the Mifi unit. I have tried the latest 2.24 testing firmware as well.
  • I can get both sims to work in a Nexx WT3020 running OpenWRT 15.05, if I manually unplug and replug the modem dongle
  • In the AR150 I have been able to get the sims to work some of the time but I'm not sure what the critical factor is. I mainly try various combinations of resetting the modem and rebooting the whole unit. What works for one attempt doesn't work for the next.
At this stage I have the following theories:
  • This might be an IPV6 issue (Not sure why it would be intermittent)
  • This has something to do with timing/dialing in a specific time after the modem is powered on
  • The network blocks too many retry attempts for an unknown period
I'm unable to find anything amiss in the logs. I will attach them below. When the connection works it looks similar to the first part of an unsuccessful connection except that the connection does not "bind" at the end and I don't get a WAN IP. I'm not sure what to do next or where I can get more diagnostic information to troubleshoot this problem.

I was just wondering if anybody here has been able to get a successful and reliable 3G connection up and running and if they could offer any tips or advice?

Please let me know if I can provide any more information, logs, config files etc.