Telvent ArcFM is described as 'ArcFM™ is a powerful extension of ESRIs ArcGIS® platform that provides a complete, enterprise utility solution geared to the needs of utility end users' and is a GIS Software in the category. There are four alternatives to Telvent ArcFM for Windows, Linux and Mac. The best alternative is Kuwaiba, which is both free and Open Source. Other great apps like Telvent ArcFM are OSPInSight (Paid), GE Smallworld Network Inventory (Paid) and Bentley Fiber V8i (Paid).
Kuwaiba is an enterprise grade, open source Network Inventory System (which covers some aspects of NGOSS/Frameworx), built on top of the Netbeans Platform and Java EE, focused on scalability, reliability, usability and interoperability.