Introduction

This document outlines the design principles and structure of the Fusion service logic deployed on the SRE platform. It provides guidelines for service providers and support teams to customize call routing while ensuring compatibility with future Fusion releases.

The Fusion service logic is organized into a hierarchy of parent and child logics, enabling modular customization without modifying the main service logic. Four main logic chains (pre-processing, inbound, outbound, and post-processing) manage different stages of call handling.

Key child service logics handle tasks such as trunk identification, number validation, application of blacklist/whitelist services, call admission control, number rewriting, and route building for various destinations including PSTN and Microsoft Teams.