[Help] Asterisk Integration with OpenBSC

Hello, I am trying to integrate SGSN, GGSN, and HLR from OpenBSC with Asterisk.
Here is exactly what I need to do:

“Use the SGSN simulator to set up an IP address for the Mobile Phone on the GGSN and then using the GTP tunneling protocol, connect a SIP phone on one side of the GTP tunnel and connect to the GGSN. The GGSN would then provide an IP interface to Asterisk. Eventually, we need to interface the HLR to Asterisk so that Asterisk can tell if the mobile phone is active and on the mobile network and what IP address to use to access the mobile phone through the GGSN.”

I have installed OpenBSC and I have osmo-sgsn, ggsn, and osmo-nitb from OpenBSC. How do I start to accomplish this? I have set up asterisk to use Google Voice with softphones. I need to do the above task with just simulation, ie: no physical base station, just software.

If I could at least get some links to read, that would be great. I have already used these links, but I’m not sure how to do it without an actual base station.
And the PDF here: openbsc.osmocom.org/trac/attachm … __v1.0.pdf

Thanks guys