LHG(G) - secondary CA B3 band auto re-connect

RouterOS Wireless Networking
1

Hi all

Router OS v7.12

I note one of my CA B3 drops occasionally and the LTE modem doesn’t auto re-negotiate to bring this secondary channel back on-line. I also note regular (every 5 seconds or so) AT command chatter to and from the mast, but last night this stopped (maybe coincidence?).

Anyone know how to (script?) auto detect a dropped secondary CA band and auto re-negotiate with the cell, preferably without disable/enable the interface as this will interrupt any connections?

Cheers
Lea

2

AT command chatter stops regularly just after midnight and CA drops the secondary B3 channel, although I’m not sure if linked (I’ll have to stay up to check!).

Others on different forums have mentioned CA should renegotiate based on aggregate load, however I see no sign in the LTE logs of this under significant bandwidth loading and CA never reestablishes unless an LTE disable/enable command is issued.

Any thoughts?

It’s frustrating to have a device capable of LTE6 (CA) and be limited to a single channel.

3

Raised a support ticket :fingerscrossed

4

After an evening / morning of investigation, it appears EE disable the secondary B3 cell overnight (power saving?) and sadly the modem doesn’t renegotiate the link (CA) at any point after.

Here’s the sequence of events:

  1. On initial connection, LTE6 negotiates primary B3 & secondary B3 CA
    2, At 12am, EE network carrier disables secondary B3 (perhaps power saving over night)
    3, LTE6 AT chatter stops as shown in lack of logging information
  2. LTE6 displays no CA and remains connected to B3 primary only, significantly reducing bandwidth
  3. At 7am, EE enables secondary B3 cell.
  4. LTE6 modem does not renegotiate connection and thus remains attached to primary B3 ONLY. Only half the bandwidth is available throughout the working day. LTE6 never renegotiates leaving the modem without CA.
    L7. LTE6 will renegotiate both primary B3 and secondary B3 (CA) if LTE6 interface is disabled/enabled after 7am (and before 12am) or device rebooted, but this is not automated by modem or RouterOS.
5

The AT chatter is directly correlated to the secondary CA, hence it stops after the cell goes off-line.

A simple scheduled script to disable / re-enable the LTE should do it, and quickly in comparison to full reboot (that takes longer than my YouTube buffer). Thanks to Mikrotik Support for assisting with this case and introducing me to MikroTik scripting.

Create a script named LTE:

/interface lte disable lte1
:delay 3s;
/interface lte enable lte1

Create a scheduler item:
/system scheduler add name="LTE" on-event=LTE interval=1d start-time=07:15:00

Not the most elegant, but still, skinning cats and all that!

6

Anyone know the answer by way of a script to Lea’s original question. My CA B3 drops occasionally and does not return until I manually disable / enable lte1.

Is it possible to detect the loss of CA B3 and auto initiate the disable and re-enable of lte1?

Thanks
Erik