OSI vs. TCP/IP Models: Key Differences Explained
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This article compares the OSI (Open Systems Interconnection) and TCP/IP (Transmission Control Protocol/Internet Protocol) models, highlighting their key differences. The OSI model provides a standardized, layered approach to network protocol architecture, while the TCP/IP model is the foundation of the internet as we know it.
Introduction
The networking world relies on models to organize and standardize communication protocols. The OSI model, with its 7 layers, serves as a conceptual framework. It’s standardized by ISO to promote interoperability. In contrast, the TCP/IP model, featuring 4 layers, is the practical model that drives the internet.
The main difference: OSI has 7 layers, while TCP/IP has 4.
The OSI model was designed to standardize the development of networking protocols and make it easier for different systems to communicate. The TCP/IP model came about through the actual implementation of working network protocols.
OSI stands for Open Systems Interconnection, and TCP/IP stands for Transmission Control Protocol/Internet Protocol.
- The OSI model splits the TCP/IP application layer into three distinct layers: Application, Presentation, and Session.
- The OSI model separates the TCP/IP network interface layer into two layers: Data Link and Physical.
- The Network (Layer 3) and Transport (Layer 4) layers remain common to both models.
Key Features Compared
- In the TCP/IP model, the Network Access layer encompasses the functionality of the Physical and Data Link layers in the OSI model.
- The OSI’s Data Link layer is further divided into two sublayers:
- MAC (Medium Access Control): Interfaces with the network adapter.
- LLC (Logical Link Control): Performs error checking for frames on the subnet and manages links.
Tabular Comparison: OSI vs. TCP/IP
The following table highlights the key differences between the OSI and TCP/IP models:
Feature | OSI Model | TCP/IP Model |
---|---|---|
Number of Layers | 7 | 4 |
Model Development | Defined before the implementation of protocol stacks. | Defined after protocol stack implementation. |
Internetworking Support | Does not natively support internetworking. | Supports internetworking. |
Layering Approach | Strict layered approach. | Loosely layered approach. |
Communication | Supports connectionless and connection-oriented communication in the network layer. | Primarily supports connection-oriented communication in the transport layer. |
Layer Direction | Horizontal layer | Vertical approach |
Session/Presentation | Separate session and presentation layers exist. | No separate session and presentation layers. |
Functionality | Characteristics of the session layer are provided by the transport layer, while characteristics of the presentation layer are provided by the application layer. | N/A |
For a deeper understanding, consider exploring the advantages and disadvantages of both the OSI and TCP/IP models.