Open Systems Interconnection Model versus Transmission Control Protocol/Internet Protocol Model
Telecommunications network models facilitate the establishment of a connection between the sender and the receiver and ensure smooth transmission of data. The two most popular telecommunications models are the Open Systems Interconnection (OSI) model and the Transmission Control Protocol/Internet Protocol (TCP/IP) model. This brief compares the OSI and TCP/IP models, specifically focusing on their similarities and differences.
Open Systems Interconnection Model
The Open Systems Interconnection model refers to a logical and conceptual framework that defines network communication utilized by systems open to communication with other systems and interconnection. Thus, the model facilitates interoperability. The Open Systems Interconnection model comprises seven layers, whereby each layer describes a different function of data traveling via a network media. The seven layers are: (1) Application, (2) Presentation, (3) Session, (4) Transport, (5) Network, (6) Data Link, And (7) Physical (Sadiku & Akujuobi, 2022).
The Physical layer defines the way bits should be moved from one device to another. Thus, it details how network interfaces, cables, and connectors are supposed to function and how to send and receive bits. An example of the Physical layer is Ethernet. The Data Link layer encases a packet in a frame. Usually, a frame contains a header and a trailer. The header and the trailer enable devices to communicate, whereby a header usually contains source information and destination address. On the other hand, the trailer comprises the Frame Check Sequence field, whose function is to detect transmission errors. Examples of the Data Link layer are PPP and HDLC (Sadiku & Akujuobi, 2022).
The Network layer details device addressing, path determination, and routing. Examples of the Network layer are IP and ICMP. The Transport layer usually segments large amounts of data originating from the upper layer protocols. The layer establishes and terminates the connection between computers. Examples of the Transport layer are TCP and UDP. The Session layer details how to establish and terminate a session between two systems. Examples of the Session layer are SSL and NetBIOS. The Presentation layer usually defines data formats. The layer defines compression and encryption. An example of the Presentation is MIME. Lastly, the Application layer enables network applications to communicate with other network applications. An example of an Application layer is HTTP (Sadiku & Akujuobi, 2022).
Transmission Control Protocol/Internet Protocol Model
The Transmission Control Protocol/Internet Protocol Model helps a user define how a specific computer must be connected to the internet and how to transmit data between multiple computers. Hence, the model helps one create a virtue network by connecting multiple computer networks. Unlike the OSI model which has seven layers, the TCP/IP model contains four layers namely Application, Transport, Internet, and Network Access. The TCP/IP model merges the Application, Presentation, and Session layers of the OSI model. In addition, the Network Access layer of the TCP/IP model combines the Data Link and Physical layers of the OSI model (Srivastava et al., 2023).
The Network Access layer defines the hardware and protocols required to ensure the delivery of data across a physical network. Examples of the Network Access layer include PPP and IEEE. The Internet layer details the protocols geared toward ensuring the logical transmission of packets over a network. Examples of the Internet layer are IPv4 and ARP. The transport layer function is to ensure reliable transmission of data and error-free delivery of packets. Examples of the transport layer include TCP and SCTP. Lastly, the Application layer defines protocols for node-to-node application communication. The layer also provides services to the application software running on a computer. Examples of the Application layer include DNS and NFS (Srivastava et al., 2023).
The obvious difference between the Open Systems Interconnection Model model and the Transmission Control Protocol/Internet Protocol Model is the number of layers. In addition, whereas the OSI model describes each of the steps needed to transfer data over a network and is particularly specific in it, the TCP/IP model is not that specific. Thus, the OSI model prescribes steps while the TCP/IP model does not.