for Gb-over-ip we need the following
1) BSC should support Gb-over-IP, we are using huawei bsc6900 in our nw here we use a FG2C card for gb-o-ip.
2) this card should be connected to a mux, it can use vlan to send the data.
3) that mux through should be connected to sgsn through transport.
4) device ip, ethernet ip, nsvlocal and nsvlremote are defined in bsc, and at sgsn end nsvl is again created.
5)now ip rotes are created in bsc.
If transport is ok then connectivity is made with sgsn, thats it.