> For the complete documentation index, see [llms.txt](https://docs.meta4d.me/n3aRZyTVBZbh3tNUbNSq/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.meta4d.me/n3aRZyTVBZbh3tNUbNSq/technical-specification/meta4d-architecture.md).

# M4M Architecture

M4M is a runtime framework to provide XR presentation of digital twins for any identities. Those digital twins interactive with multiple XR systems or metaverses, thus the presentation can be shared accordingly.

![M4M reference architecture](https://3035362353-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcdlNgmirFVO6p9w35Xox%2Fuploads%2Fgit-blob-0057f1160b8db945aafdb46e9f9dd80408e724e1%2Fmeta4d-architecture.png?alt=media)

The architecture of M4M includes four layers,

1. [**Protocol layer**](/n3aRZyTVBZbh3tNUbNSq/technical-specification/protocol-layer.md). Provides a series of standard or protocols for presentation tracing and statistics, static modeling and storage, and dynamic presenting.
2. [**Meta layer**](/n3aRZyTVBZbh3tNUbNSq/technical-specification/meta-layer.md). Resource management for meta of static modeling and dynamic presentation.
3. [**Present layer**](/n3aRZyTVBZbh3tNUbNSq/technical-specification/present-layer.md). Runtime network for digital twin presenting cross XR systems or metaverses.
4. [**Application layer**](/n3aRZyTVBZbh3tNUbNSq/technical-specification/application-layer.md). Applications for self-sovereign twin presentation management. Provides capability for common sharing or presentation interoperability.