Hi kodiagnon, Can you pls specify what do you want to dimention in the interface. In normal condition it is connected via STP or even if there is no STP there is only singnalling connectivity between MSC and HLR.Signalling connectivity could be anything like SIGTRAN or SS7 links so you have to plan signaling link accordingly based upon which type of connectivity you have as you can have only 16 links between two point codes you can have upto maximum 16 links between MSC and HLR, so depending upon subscriber capacity you need to connect links and depending upon traffic you can upgrade it from 64 kbps to 128 kbps or 256 kbps.kindly describe your question.