Standards and interoperability: which international, multilayered reference model and set of protocols was created to promote compatibility among telecommunications and computer networks worldwide?

Introduction / Context:
Interoperability across vendors and countries requires a shared framework describing layers, interfaces, and services. The best-known international effort providing such a framework is an ISO/IEC model that influenced generations of networking curricula and protocol design.

Given Data / Assumptions:

• Goal: promote compatibility and interoperability among heterogeneous networks.
• Scope: international, multi-level (layered) model and protocols.
• Looking for a standards-based answer, not a product.

Concept / Approach:
The Open Systems Interconnection (OSI) reference model defines seven layers from physical up to application, along with associated service primitives and protocol concepts. While the Internet largely standardized on TCP/IP, OSI provided the vocabulary and abstraction widely used in education and design. Other options refer to products or broad concepts and do not meet the international, multilayer model criterion.

Step-by-Step Solution:

Verification / Alternative check:
ISO/IEC publications and textbooks describe OSI as the canonical layered reference model with specified services and protocols.

Why Other Options Are Wrong:

Common Pitfalls:
Confusing the OSI model with specific Internet protocols; OSI is a model and family of standards, not a single protocol suite used on today’s Internet.

Final Answer:
OSI.