MTP Level3 is indeed implemented in libosmo-sccp, which provides the foundational support for SCCP (Signalling Connection Control Part) services on top of MTP3. A practical example of this implementation can be observed in cellmgr_ng, where SCCP is integrated with MTP Level3 to handle signalling for telecom network infrastructure. In cellmgr_ng, MTP3 frames are typically received via UDP, providing a simplified simulation interface, but in real-world deployments, the source and sink of these frames would be hardware-dependent, such as E1 or T1 interface cards, or specialized IP signalling gateways. This layered modularity is quite similar to how complex systems in other fields are designed—for instance, in book cover design @ https://www.britishbookdesign.co.uk, where layout tools (like InDesign or Affinity Publisher) sit on top of rendering engines, which in turn rely on lower-level graphical APIs. Just as MTP3 abstracts the routing and management of SS7 messages from the physical transport, a solid book cover design framework abstracts aesthetics and branding from the nitty-gritty of pixel rendering and format compliance.