# Metaverse Architectures: A Comprehensive Systematic Review of Definitions and Frameworks
## 4 Discussion
### Metaverse Architecture  
A total of 25 architectural models have been identified in the literature, categorised into three primary groups: general layered architectures, domain-focused architectures, and technology-based architectures. This study primarily focuses on the comprehensive analysis and comparative assessment of general layered architectures, while all three categories contribute to the architectural debate regarding the metaverse.  
Layered metaverse architectures, comprising three to six layers, provide modular, abstract frameworks that enable the methodical conceptualisation and structural organisation of the metaverse across many areas. In contrast, domain-specific architectures are typically designed for specialised industries such as healthcare, education, or manufacturing, and hence, they lack the versatility needed for wider applications. Although technology-based architectures effectively highlight enabling infrastructures like artificial intelligence, blockchain, extended reality, 6G, and digital twins, they frequently lack a clearly defined layered structure that systematically organises system components. Thus, while these architectures elucidate the technological foundations of the metaverse, they fail to offer comprehensive architectural frameworks appropriate for cross-domain applications.  
The classification of architectural models revealed instances where design intent and application domain were not perfectly aligned. One architecture [101], which targeted the e-commerce domain, was included under technology-based architecture because of its explicit emphasis on blockchain infrastructure. This highlights the analytical tension between functional deployment and conceptual orientation, necessitating interpretation based on authorial framing and structural design focus, rather than domain alone.  
Moreover, both domain-specific and technology-oriented architectures frequently fail to satisfy critical needs such as modularity, scalability, interoperability, and data security, which are vital for extensive industrial use. Consequently, there is a considerable demand for versatile metaverse designs that can support sectoral diversity while ensuring a comprehensive and adaptive framework. This paper analyses how layered architectures conceptualise the metaverse and aims to discover recurring functional components, structural similarities, and their progression across different approaches.  
The study analyses general-purpose metaverse architectures by concentrating on a set of well-established models that exhibit conceptual clarity, structural coherence, and widespread acceptance in the literature. These frameworks were selected for their impact on metaverse design discourse and their embodiment of fundamental, domain-agnostic architectural methodologies. The study facilitates a targeted comparison examination by focusing on a selection of exemplary models that provide modular layered frameworks. This method enables the recognition of repetitive structural patterns, thematic uniformities, and essential conceptual components that support the building of overarching metaverse systems.