  Multi-Access or Mobile Edge Computing (MEC) is being deployed by 4G/5G
operators to provide computational services at lower latencies. Federating MECs
across operators expands capability, capacity, and coverage but gives rise to
two issues - third-party authentication and application mobility - for
continuous service during roaming without re-authentication. In this work, we
propose a Federated State transfer and 3rd-party Authentication (FS3A)
mechanism that uses a transparent proxy to transfer the information of both
authentication and application state across operators to resolve these issues.
The FS3A proxy is kept transparent, with virtual counterparts, to avoid any
changes to the existing MEC and cellular architectures. FS3A provides users
with a token, when authenticated by an MEC, which can be reused across
operators for faster authentication. Prefetching of subscription and state is
also proposed to further reduce the authentication and application mobility
latencies. We evaluated FS3A on an OpenAirInterface (OAI)-based testbed and the
results show that token reuse and subscription prefetching reduce the
authentication latency by 53-65%, compared to complete re-authentication, while
state prefetching reduces application mobility latency by 51-91%, compared to
no prefetching. Overall, FS3A reduces the service interruption time by 33%,
compared to no token reuse and prefetching.
