.. SPDX-FileCopyrightText: © 2020 Open Networking Foundation SPDX-License-Identifier: Apache-2.0 .. _design_smf: SMF Design Overview =================== .. image:: ../_static/images/CN-SMF.png :width: 500px UPF-Adapter ----------- As UPF may not support connections from multiple SMF instances with same Node-Id, UPF-Adapter layer has been introduced. * UPF-Adapter acts like Mux-Demux for PFCP messages between multiple SMF instances and UPF. * SMF sends custom PFCP msg to UPF-Adapter if UPF-Adapter is deployed. * The UPF-Adapter intercepts and modifies certain fields before sending PFCP msg to actual UPF. * Similar handling is done for the response from UPF towards SMF.