The telecommunications industry is defined by perpetual evolution and increasing complexity. As communication networks have advanced— from foundational concepts like the OSI and TCP/IP models, through the rapid evolution of mobile generations (2G to 5G), to modern technologies such as IoT, SDN, and NFV—the need for sophisticated management systems has become paramount. The core challenge for Communications Service Providers (CSPs) is not just building powerful networks, but operating and main taining them profitably to deliver a superior customer experience. This is the domain of Operations Support Systems (OSS) This book, Fundamentals of Network and OSS, serves as a compre hensive, practical guide to demystify this critical, often jargon-filled field. It establishes a solid foundational understanding of both the Telecom Network and the Operational Support Systems that form the industry’s operational backbone.