Comparison between TCP/IP and OSI Model

May 11, 2025 •6 min read•CCNA

Comparison between TCP/IP and OSI models is critical because protocols that make up the TCP IP protocol suite can also be described in terms of the OSI reference model. The network access layer and application layer of the TCP IP models are further divided, and the OSI model describes discrete functions that must occur at these layers. Both models are widely used networking models for communication. The critical difference between the two is that OSI is a conceptual model that is not practically used for communication. In contrast, TCP IP establishes a connection and communicates through the network.

Table of Contents

The network Access layer of the TCP/IP model does not specify which protocols to use when transmitting over a physical medium. It only describes the handover from the Internet layer to the physical layer. On the other hand, the OSI Layer physical and data link layers discuss the basic process of accessing the media and the physical means of sending data over a network.

Network Layer of OSI and Internet Layer of TCP/IP Model

The network layer maps directly to the TCP/IP Internet layer. This layer explains protocols that address and route messages from end to end an internetwork.

Transport Layer

The transport layer maps directly to the TCP IP Transport layer. This layer explains the general services and functions that ensure the ordered and reliable delivery of data between source and destination hosts.

TCP/IP Application Layer

The application layer of the TCP IP model includes several protocols that give specific functionality to various end-user applications. The OSI Model Layers 5, 6, and 7 used as references for application software developers and vendors to produce products that operate on networks.

Comparison between TCP/IP and OSI Models Protocols

Both the TCP IP and OSI models commonly used when referring to protocols at various layers. OSI is a generic, protocol-independent standard, acting as a communication gateway between the network and end user. TCP/IP model is based on standard protocols around which the Internet has developed. It is a communication protocol, which allows connection of hosts over a network. OSI is a reference model around which the networks built. Generally, it is a guidance tool.TCP IP model is, in a way implementation of the OSI model.

TCP/IP Layers

OSI Layers

Key Responsibility

Common Protocols

Application Layer	Application Layer	User Application Services	DNS, NFS, BOOTP, DHCP, SNMP, RMON, FTP, TFTP, SMTP, POP3, IMAP, NNTP, HTTP, Telnet
	Presentation Layer	Data Translation, Compression and Encryption	SSL, Shells and Redirectors, MIME
	Session Layer	Session Establishment, Management and Termination	NetBIOS, Sockets, Named Pipes, RPC

Transport Layer

Process-Level Addressing, Multiplexing/ De-Multiplexing, Connections, Segmentation and Reassembly, Acknowledgments and Retransmissions, Flow Control

TCP and UDP, SPX, NetBEUI/NBF

Internet Layer

Network Layer

Logical Addressing, Routing, Datagram Encapsulation, Fragmentation and Reassembly, Error Handling and Diagnostics

IP, IPv6, IP NAT, IPsec, Mobile IP, ICMP, IPX, DLC, PLP, Routing protocols such as RIP and BGP

Network Access Layer	Datalink Layer	Logical Link Control, Media Access Control, Data Framing, Addressing, Error Detection and Handling, Defining Requirements of Physical Layer	IEEE 802.2 LLC, Ethernet Family, Token Ring, FDDI and CDDI, IEEE 802.11 (WLAN, Wi-Fi), HomePNA, HomeRF, ATM, SLIP and PPP
Network Access Layer	Physical Layer	Encoding and Signaling, Physical Data Transmission, Hardware Specifications, Topology and Design	Physical layers of most of the technologies listed for the data link layer

OSI has 7 layers and TCP has 4 Layer model. following is the comparison model of both layer.

Key Differences between TCP/IP and OSI Model

Feature	TCP/IP Model	OSI Model
Layers	4 layers	7 layers
Design Philosophy	Top-down (practical)	Bottom-up (theoretical)
Real-World Use	Internet standard	Conceptual framework
Protocol Dependency	Protocol-specific (IP, TCP)	Protocol-agnostic
Tangibility	Implemented in practice	Abstract reference tool

Critical Distinctions

Purpose:

TCP/IP is a protocol suite used globally for internet communication.
OSI is a theoretical model for standardizing network functions.

Layer Architecture:

TCP/IP combines OSI’s Layers 5–7 into a single Application layer.
OSI explicitly separates services (e.g., Session vs. Presentation layers).

Adoption:

TCP/IP dominates modern networks due to its simplicity and scalability.
OSI guides protocol design but is rarely implemented in full.

Approach:

TCP/IP follows a client-server architecture.
OSI emphasizes modularity for interoperability.

Practical Implications

Developers: Use OSI to design cross-compatible software (e.g., VPNs leveraging Layer 3).
Network Engineers: Rely on TCP/IP for configuring routers, firewalls, and servers.
Troubleshooting: OSI’s layered structure helps isolate issues (e.g., physical vs. application-layer faults).

Conclusion – Comparison between TCP/IP and OSI Models

While the OSI model provides a comprehensive framework for understanding networks, TCP/IP is the backbone of modern connectivity. Their comparison underscores the importance of balancing theoretical concepts (OSI) with real-world implementation (TCP/IP). For deeper insights, explore: