Are there any rules for Dynamic IP Address Allocation to Mobile Handsets
When a data session is established by a mobile phone, the GGSN assigns an internal IP address to the mobile terminal (cell phone). But do Service Providers further control how the IP addresses get assigned – for example, dedicate a certain range for each Routing Area (RA). Or dedicate a certain range for each phone model ….
IP addesses allocation for mobile phones follow same principles as for any other fixed private IP networks (e.g. any corporate); Service Provides allocates IP address only for Access Points outside of GGSN.
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.