This feature adds support for seamless inter WLAN-GW mobility when a UE roams from an AP behind a WLAN-GW to an AP behind another WLAN-GW. Before this feature, inter-WLAN-GW mobility was supported by creating a UE state on the target WLAN-GW based on a data-trigger and carries over its L2-aware NAT inside IP address to the target WLAN-GW. However, the outside NAT pool (and therefore the outside IP) changes, and any traffic for existing sessions is dropped. This feature introduces the concept of ‟home WLAN-GW” (H-GW) that provides an anchor point for a UE when it roams to an AP behind a different WLAN-GW, referred to as ‟visited WLAN-GW” (V-GW). With anchoring on the H-GW, the UE retails both its NAT inside and outside IP addresses. Existing NAT flows on the H-GW stay intact, and forwarding is seamless, as shown in Figure: Dynamic tunnel x-connect for seamless inter-WLAN-GW mobility. The V-GW tunnels the UE traffic to the H-GW that anchors the UE.
