Cellular Network Infrastructure

Quickly testing a 3G setup on current master, I see signalling is working, but voice RAB Assignment fails.
I see osmo-mgw saying:

20180723172416621 DRTP ERROR mgcp_network.c:835 endpoint:0x0 data from wrong address: 192.168.0.124, expected: 0.0.0.0
20180723172416621 DRTP ERROR mgcp_network.c:839 endpoint:0x0 packet tossed

This is the IuUP Initialization message that we should respond to with an IuUP Initialization ACK.

a) Apparently we are no longer telling the osmo-mgw the femto cell's IP address on time.

b) AFAICT we still have that IuUP hack in osmo-mgw to patch the looped back IuUP Initialization to an IuUP Initialization Ack, but the proper implementation is asked for in #2459 / #1937