The document discusses providing seamless handoff between heterogeneous wireless networks. It proposes using mobile IP with extensions to allow a multimode terminal to handoff between a wireless local area network (WLAN) and a wireless wide area network (WWAN). A testbed was built to evaluate handoff delays and packet loss when switching between the networks. Results showed handoff delays of around 600ms for WLAN to WWAN and 1040ms for WWAN to WLAN, with small packet loss.

1. Seamless Handoff Between Heterogeneous Wireless Networks Haipeng Jin and Kameswari Chebrolu, UCSD Aditya Pande and Xiaohua Chen, Stanford University Javad Razavilar, Magis Networks Inc., San Diego Barani Subbiah, 3Com Corp., Santa Clara

7. Mobile IP CH HA FA MT Packets destined for mobile Packets in reverse direction Encapsulated packets

9. Handoff Algorithm

12. Testbed

15. SNR measurement on WLAN

16. Switching from WLAN to WWAN

17. Delay on WLAN

18. Delay while handoff