osmo-dev/virt-nitb

This is runs a complete core network with a virtual 2G BTS and two virtual 2G phones.

Steps:

- build osmocom-bb
    git clone https://gerrit.osmocom.org/osmocom-bb
    cd osmocom-bb/src
    make nofirmware
    cd ../..
  Put programs virtphy and mobile in $PATH, e.g.
    ln -s $PWD/osmocom-bb/src/host/virt_phy/src/virtphy ~/bin/
    ln -s $PWD/osmocom-bb/src/host/layer23/src/mobile/mobile ~/bin/

- also have these programs available in $PATH:
  - osmo-hlr
  - osmo-msc
  - osmo-mgw
  - osmo-stp
  - osmo-bsc
  - osmo-bts-virtual (from osmo-bts)
  - did i miss one?

- prepare HLR db; call this while no other osmo-hlr is running:
    ./create_hlr_subscribers.sh

- use run.sh to launch N terminals with one component each:
    ./run.sh
  when you hit enter in this terminal, the entire network is torn down. (so continue in another terminal)
  - of course you can instead launch the ten-odd components manually...

- Two virtual phones should subscribe to the network as soon as the two 'mobile' are launched.
  Watch for 'bssap': "Location Updating Accept" with wireshark tracing 'lo'

- Launch (the signalling of) a voice call:
    ./call.sh
    ...
    ./hangup.sh
  There will be no voice RTP stream, but the MGWs will be set up for it and the call will remain open.

- ...