UniFi Network is described as 'The UniFi® Network application is a Software-Defined Networking (SDN) platform, which provides an end-to-end system of network devices across different locations — all controlled from a single interface' and is an app in the network & admin category. There are eight alternatives to UniFi Network for a variety of platforms, including Linux, Self-Hosted, Web-based, Windows and Mac apps. The best UniFi Network alternative is RadiusDesk, which is both free and Open Source. Other great apps like UniFi Network are OpenWISP, tp-link Omada, OpenDaylight and Cisco Meraki Systems Manager.
https://alternativeto.net/software/cisco-meraki-systems-manager/ is not a Software-Defined Network Solution, Cisco Meraki SM is the Mobile Device Management Part of https://alternativeto.net/software/cisco-meraki/. However https://alternativeto.net/software/cisco-meraki/ itself is a cloud-based SDN.