1. NTUA, July 2006 Mobile VPN over WLAN a Teleservice of the UMTS C. F. Grecas, I. S. Venieris

2. NTUA, July 2006 2 VPN’s Structure The public nature of the facilities connecting the sectors of the VPN is not perceived by the users

3. NTUA, July 2006 3 The Mobile VPN architecture employing the UMTS’s core network

4. NTUA, July 2006 4 The WLAN’s basic architecture DS: Distribution System (Ethernet) AP: Performs the wireless-to-wired bridging function BSA: Basic Service Area covered by a single AR ESS: Linkage of two or more BSAs belonging to the same DS

5. NTUA, July 2006 5 The UMTS structure

6. NTUA, July 2006 6 The protocol stack modification of the SGSN For the requirements of the Mobile VPN the SGSN degenerates into a typical layer 3 router

7. NTUA, July 2006 7 The protocol stack modification of the GGSN Similar “horizontal” extension are made to the GGSN protocol stack

8. NTUA, July 2006 8 The VPN's subnets connected to the UMTS Core Network. Every WLAN section constitutes an ESS All the MSs are registered as members of every ESS

9. NTUA, July 2006 9 The Location Update mechanism (IP layer) Host-specific routes ICMP packets

10. NTUA, July 2006 10 Traffic Handling within the MPVN Within the same ESS (WLAN resources/techniques) Between different ESSs (Section Router, PLMN platform ) To and from the public Internet (Section Router)

11. NTUA, July 2006 11 Cohabitation with the conventional UMTS services The coexistence with the rest of the UMTS services is to be assured by the cell granularity of the UMTS cells The system specifications foresee even the employment of pico-cells in the areas of heavy traffic A trade off should be adopted between the UMTS and WLAN Mobile Station following the QoS guaranteed