1. Multiple Gateways Project E6951 2002 Spring Professor Campbell Group members: Adrija Biswas, Will Jenkins, Charalampos Mantelis, Naoya Seta, Nil Unerdem

2. Objectives Modify the current Cellular IP implementation, so as to support multiple gateways Verify the modified protocol using the ns simulator

3. Approach MH GW2GW1 RBS BS1BS2 BS3 BS4 CH

4. NS-2 Simulator Main Module Random Load Generator Gateway Switcher gw1_load gw2_load Periodic call Write Read Call Global SwitchGW{} Switch-watchdog{}Call UpdateLoad{} LoadCheckGW{}

5. Main Module Topology Setup Initialization of Nodes Link Setup Traffic patterns setup Initialization of Gateway Switcher and Random Number Generator modules

6. Random Load Generator Periodically generates random numbers for each gateway Updates load variables

7. Gateway Switcher Periodically checks load value Compares to threshold Switches gateway

8. Up-link NS-2 Simulator Gateway – Set global load-variable Random Number Generator (Exponential) Base-Station – Load balancing Check load-variable Gateway switching Mobile Host – Watchdog module

9. Down-link NS-2 Simulator Gateway – Handoff Similar to hard handoff (potential packet loss) Base-Station – Routing Reverse path routing Mobile Host

10. Future Proposals Load Balancing implemented through Gateway Beacons Some sort of semi-soft handoff during gateway switch Mesh topology (dynamic configuration) – with base stations broadcasting to one another.