This chapter lays the theoretical and conceptual groundwork for modelling IoT-5G interconnection systems within the “divide and conquer” (DC) paradigm. It formalizes distributed service architectures in which incoming requests are decomposed into synchronized subrequests, processed in parallel by specialized servers, and reassembled upon completion. The chapter introduces several DC-like system types—including Split-Merge (SM), Fission–Fusion (FF), Team Service Models (TSM), and Independent Server Models (ISM)—and evaluates their fundamental properties through queuing theory. Special attention is given to interdependencies between service queues, synchronization bottlenecks, and the probabilistic nature of service time distributions. A comprehensive analysis of a symmetric two-server model with Poisson input and exponential service is provided using continuous Markov processes and generating functions. Various approximation strategies, including the use of harmonic means, ordinal statistics, and heavy/light traffic interpolation (H<IA), are examined to estimate key performance metrics such as system response time and synchronization delays. This chapter serves as a foundational framework for further mathematical generalizations and simulations of DC-like systems under practical and extreme operating conditions.