A device can reach the 5G core over a network the operator does not own. The non-3GPP interworking function is the gateway that makes that possible — and it matters most where cellular coverage is poor, spectrum is unavailable, or an enterprise already has a wireless network it would rather keep.
The 5G core expects to authenticate a subscriber and manage sessions. It does not, in principle, require that the subscriber arrived over 3GPP radio. The non-3GPP interworking function is what allows a device on a Wi-Fi network to present itself to the core as though it had.
The device establishes a secure tunnel to the interworking function over whatever IP connectivity it has. Signalling that would normally traverse the radio interface is carried inside that tunnel, and once established the core treats the session much as it would a cellular one — same identity, same policy, same session management.
The distinction that matters is trusted against untrusted access. Untrusted access assumes the intervening network is hostile and secures everything end to end to the interworking function. Trusted access, where the operator has a relationship with the access network, permits a lighter arrangement. Most enterprise deployments are untrusted, because the operator does not control the Wi-Fi.
The non-3GPP interworking function: a gateway allowing a device to reach the 5G core over a network that is not 3GPP radio, typically Wi-Fi. The device builds a secure tunnel to it, and signalling that would normally cross the radio interface is carried inside that tunnel.
Untrusted access assumes the intervening network is hostile and secures everything end to end to the interworking function. Trusted access, where the operator has a relationship with the access network, allows a lighter arrangement. Enterprise deployments are usually untrusted, because the operator does not control the Wi-Fi.
Because it requires no licensed spectrum and no cellular radio deployment. Where a building already has good Wi-Fi and poor cellular penetration, extending core services over the existing network is considerably cheaper than building coverage.
Mainly that the intervening network is not under operator control, so latency and loss cannot be managed the way radio resources can. Tunnel establishment also costs time and battery, mobility between access types is where implementations differ most, and device support is uneven.
Written for engineers. Share it with one.
The sharing models.
PRODUCTThe licensed alternative.
TECHNOLOGYWhat the tunnel carries.
SOLUTIONCoverage layers.
TECHNOLOGYWhere the work belongs.
INDUSTRYOperator context.
Tell us the specification, the constraint and the deadline. Programmes that cross silicon, radio, embedded and AI are where Faststream is strongest.