Architectures for Seamless Roaming in 3GPP- WLAN Integration

Seamless roaming between the third generation wireless networks and wireless local area networks can be provided using Mobile IP. However, 3GPP and 802.11-based networks have no native support for Mobile IP. Mobile IP requires the deployment of the home agents and a protocol between the mobile nodes, home agent and the corresponding nodes. We address the home agent placement and home address assignment issues for supporting Mobile IP in 3GPP and 802.11based networks. Placement techniques for Mobile IP home agents are presented including dynamic HA assignment in either WLAN or GPRS/UMTS domains using Diameter Mobile IP application. Next, we present several IPv4 home address assignment schemes for mobile nodes visiting in WLAN domain such as the mobile VPNs, NAT/NAPT traversal and reverse tunneling. It is shown that HA placement and address management are orthogonal and any combination is possible. Various architectures for both issues are evaluated against the optimal solutions.