Distributed RADIUS proxy for closed SSID

An existing distributed RADIUS proxy (as described in Distributed RADIUS proxy) can be enabled on both the H-GW and V-GW. Authentication and accounting messages are proxied to configured AAA servers. When the UE state exists on the V-GW, any authentication and accounting messages are visible on the H-GW and are proxied directly to the configured AAA server from the V-GW. Data-triggered mobility must be enabled on the H-GW, as it cannot rely on authentication and accounting messages to infer UE mobility when the UE is on V-GW.