Bug #4153

3G voice broken with ALu 9361 femto

Added by dev_zzo about 2 years ago. Updated 5 months ago.

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I am trying to create a setup with various Osmocom components to get the Alcatel-Lucent 9361 femtocells I have to function as a small 3G network. Currently, I am experiencing issues with 3G voice calls, quite similar to the ones described in #3411 / #2459 / #1937: the voice call is dropped.

I have traced the issue to the following code:

The femtocell rejects the IuUP message due to a CRC mismatch and indeed, when the bytes are patched, the header CRC is not updated and therefore cannot match.


#1 Updated by laforge about 2 years ago


Thanks a lot for your detailed bug report. The lack of proper IuUP support has been
haunting us for a long time. I once started to implement the related state machines
in libosmocore, see the 'laforge/iu_up' branch. However, nobody has yet found the time
or resources to integrate that properly into osmo-mgw and test it :/


#2 Updated by dev_zzo about 2 years ago

I will be happy to test any updates against my setup. Unfortunately, I am not much of a IuUP expert (I wish I were!) and probably won't be able to help out with development except build/run/verify.

Kindest regards,

#3 Updated by Vengant 9 months ago

Hi dev_zzo,

Would you please share any details about gaining root access to ALu 9361 in order to use it with Osmocom?

#4 Updated by limeanalog 5 months ago

Hi dev_zzo,

I would also like to know how you've connected this to Osmocom? any info would be much appreciated.

#5 Updated by dev_zzo 5 months ago

I see there is interest in popping some femtos, glad to see that. Unfortunately, right now I'm a bit overloaded with stuff and can't quite sit down and do an extensive writeup, but I'll try to find some time to do it eventually.

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