Terminology » Networking Basics » OSI vs. TCP/IP Models: Key Differences Explained

OSI vs. TCP/IP Models: Key Differences Explained

osi model tcpip model network protocol layer architecture data communication

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.

OSI and TCPIP

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:

FeatureOSI ModelTCP/IP Model
Number of Layers74
Model DevelopmentDefined before the implementation of protocol stacks.Defined after protocol stack implementation.
Internetworking SupportDoes not natively support internetworking.Supports internetworking.
Layering ApproachStrict layered approach.Loosely layered approach.
CommunicationSupports connectionless and connection-oriented communication in the network layer.Primarily supports connection-oriented communication in the transport layer.
Layer DirectionHorizontal layerVertical approach
Session/PresentationSeparate session and presentation layers exist.No separate session and presentation layers.
FunctionalityCharacteristics 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.