#7 OSI vs TCP/IP MODEL: THE NETWORKING SERIES
Are you online? Of course you are! And that’s how you are reading this blog right now. Would you like to know how this is possible? This series is all about what it takes to be online and access internet!
Hey peeps, you know how a network is constructed and how to configure a network. Continuing to this, we are going to discuss about the most popular networking models, “OSI Model” and “TCP/IP Model”. These models provide help us to visualize how the various protocols work together to enable network communications.
But, before moving into these models, let’s take a look at some of the common networking protocols.
- Hypertext Transfer Protocol (HTTP): This governs the interaction between a web server and a web client. It defines the content and formatting of the requests and responses that are exchanged between the client and server.
- Transmission Control Protocol (TCP): This protocol manages the individual conversations. TCP is responsible for guaranteeing the reliable delivery of information and controlling the flow between the end devices.
- Internet Protocol (IP): This is responsible for delivering information from the sender to the receiver. It is used by routers to forward messages across multiple networks.
- Ethernet: This protocol is responsible for the delivery of messages from one NIC to another NIC on the same Ethernet LAN.
The TCP/IP Model
The first layered model for internetwork communication was referred to as the internet model. It defines a four categories of function that is carried out during a communication in order to be successful. The suite of TCP/IP protocols used for internet communication follows the structure of this model. Hence, this model is known as “TCP/IP Model”.
Layers of TCP/IP Model
- Application: Represents data to the user, encoding and dialog control
- Transport: Enables communication between various devices across networks
- Internet: Determines the best path through the network
- Network Access: Controls hardware devices and media that make up the network
The OSI Model
This most widely known interconnection model was created by the Open Systems Interconnection (OSI) project at the ISO. It is used for data network design, operation specifications and troubleshooting.
Layers of OSI Model
- Application: This layer contains protocols used for process-to-process communications.
- Presentation: Provides common representation of the data transferred between application layer services.
- Session: Provides services to presentation layer to organize its dialogue and to manage data exchange.
- Transport: Responsible to segment, transfer and reassemble the data for individual communications between end devices.
- Network: Provides services to exchange the individual pieces of data over the network.
- Data Link: This layer protocols define the methods for exchanging data frames between devices over a common media.
- Physical: Describes the physical connections for transmission of a bit from and to a network device.
The data transmission across a network can be easily visualized using the seven layers of the OSI model. The OSI model breaks down the network communications into multiple processes. Each process is a small part of a larger task.
OSI and TCP/IP Model Comparison
The TCP/IP model visualizes the interactions of various protocols that make up the TCP/IP protocol suite. It does not describe the general functions that are necessary for network communications. This model explains the networking functions that are specific to those protocols in use in the TCP/IP model. To illustrate, at the network access layer of TCP/IP model, it does not specify which protocol to use when transmitting over physical medium nor the encoding methods that are performed for transmission of the signals. Whereas, OSI Layer 1 and Layer 2 discuss the necessary procedures to access the media and the physical means for sending a data over a network.
The protocols that make up the TCP/IP protocol suite can be described in terms of the OSI reference model. Like, the functions that occur at the “internet layer” in the TCP/IP model is contained in the “network layer” of the OSI model. The “transport layer” functionality is same in both the models. However, the “network access layer” and “application layer” of the TCP/IP model is further divided into two layers in the OSI model.
Both TCP/IP and OSI models are commonly used when referring to protocols at various levels. However, while referring to lower levels, OSI model is preferred as it separates the “data link layer” from the “physical layer”.
Now, you are familiar with the common models used in network communications. I’ll catch you up in the next blog with another interesting topic!
Stay connected!!
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