To elaborate, if a carrier is rather big and if they have more than 1 GGSN and if they are located in different areas, it depends on what SGSN’s are pointed to the particular GGSN in the DNS. If you have SGSN group A pointed to GGSN group A and SGSN group B point to GGSN B, then the SGSN group A will only assign the mobile pool for a specific APN as per what is configured in GGSN A. In this case, it is what IP the mobile picks up on is not dependent of the RA but rather the SGSN that it ultimately is served by. Hope this helps.