I am playing a game on the 3G network using Android or Iphone. Suppose I am moving from one cell to another; Will the IP Address change? If yes, then how can I continue the same game while changing the base station, as my IP address is already registered in The game server? Is there something DHCP?

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    \$\begingroup\$ This really depends on the carrier, but usually the IP survives the handover between two 3G cells (otherwise your IP would change pretty often because 3G cells are really small, nothing compared to a GSM cell) \$\endgroup\$ – JustSid Apr 29 '11 at 8:06
  • \$\begingroup\$ Suppose that IP is used in another Cell then How switching of IP to new will take Place.As i have to send the new IP to server n replce the old IP. \$\endgroup\$ – GameBuilder Apr 29 '11 at 12:27
  • \$\begingroup\$ @GameBuilder: The IP can't be used in the other cell, unless it belongs to a complete different operator. \$\endgroup\$ – JustSid Apr 29 '11 at 13:52
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    \$\begingroup\$ @GameBuilder: The IP has nothing to do with the radio cell! IP assignment is something that your carrier does. The radio towers are connected to a "Node B". In a cellular network there are many "Node B"s. These are then connected to your carriers network. Whithin that network there might be a DHCP or some other "IP-Address distribution". Really, 3G is the physical and the media access control layer! \$\endgroup\$ – Lurca Apr 29 '11 at 14:21
  • \$\begingroup\$ That means OPERATOR gives Fixed IP address to smart phones.IP doesnt changes even we are changing the BST. \$\endgroup\$ – GameBuilder Apr 29 '11 at 17:44

Just as @JustSid said, if you move from one cell to another the handover is handled transparently. The 3G network is just the method of transportation of your data packets, therefore it is a few layers below the IP layer, if you think in terms of the ISO/OSI stack. I worked on a push-to-talk application for mobile phones and all i can say is, that we never dealt with 3G cell changes. We just opened a TCP connection and started sending packets. One thing that also depends on your carrier is the 3G <-> 2G handover. With some carriers it worked fine, with some others we had disconnects.

  • \$\begingroup\$ +1. You might want to add that obviously you could get a new IP from a temporary complete disconnect (no *G whatsoever) - some carriers might hold onto an IP for you for a few minutes though. An effective way around this is to send a client a 'session ID' that they can reconnect to. On second thoughts don't bother: he doesn't accept any answers - even after being told to. \$\endgroup\$ – Jonathan Dickinson Jan 25 '12 at 14:12

A HTTP request from a mobile device is routed through a WAP Gateway. These are maintained by the mobile network operators. The WAP Gateway routes the request to the desired server and returns the response to the client.

As far as I know, IP routing on a mobile phone has nothing to do with cell tower base stations as everyone on the same network would be routed through these gateways.


An effective way around this is to send a client a 'session ID' that they can reconnect to IP.

Allocate 2 IPs to the mobile - one of them stays constant (the identifier) & one which varies, (the location). This is termed 'Tunnel-based'.


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