Ribbon Communications makes networking software and hardware for telecom carriers and enterprises, with two core product lines. The Cloud and Edge segment (~60% of revenue) provides voice infrastructure — Session Border Controllers (SBCs), call controllers, media gateways, and application servers — that helps carriers and large enterprises replace aging TDM and copper-based voice networks with modern, software-based IP platforms. The IP Optical Networks segment (~40% of revenue) provides IP routing, switching, and optical transport hardware and software for service providers and critical infrastructure customers. Ribbon's largest customer is Verizon, at ~17% of revenue, with the top five customers representing ~41% of revenue. Ribbon sells to carriers via direct sales and to enterprises via channel partners. Revenue comes from three streams: upfront hardware and software licenses, professional services tied to network deployments and migrations, and recurring maintenance and support contracts. Cloud and Edge carries gross margins around 64-68%, while IP Optical runs closer to 35%. Ribbon's primary growth opportunity is voice modernization — replacing legacy switching infrastructure at large U.S. carriers, with a multi-year Verizon program to decommission hundreds of central office switches as the flagship example. Secondary growth drivers include North American fiber broadband buildouts, India IP Optical expansion (its fastest-growing market), and positioning its cloud-native voice infrastructure as an interface layer for AI-driven voice applications.