4 Layers of the TCP/IP Model vs OSI Reference Model

4 Layers of the TCP/IP Model vs OSI Reference Model

4 Layers of the TCP/IP Model

Transmission Control Protocol/Internet Protocol (TCP/IP) is the suite of Internet Protocols which is used to communicate over the internet. After the Open System Interconnection (OSI) Reference Model, the TCP/IP model was come into form because of two major reasons. First one is, the base of the internet was created using TCP/IP suite and through the increase of the World Wide Web and internet, TCP/IP model has been chosen. Second reason is, a project researched by the Department of Defense (DOD) consisted of creating the TCP/IP protocols. The DoD model’s targets was to fetch international standards which would not be match by the OSI reference model. The DoD model was the biggest software consumer and the Department of Defense most like the TCP/IP suite, many merchants used TCP/IP model instead of Open System Interconnection (OSI) Reference model.

Comparison of the TCP/IP and OSI Reference Models:

4 Layers of the TCP/IP Model vs 7 Layers of the OSI Reference Model

4 Layers of the TCP/IP Model vs 7 Layers of the OSI Reference Model

The Transmission Control Protocol/Internet Protocol (TCP/IP) model is similar to the Open System Interconnection (OSI) Reference Model which contains on layers.  There are seven layers in the OSI reference model and while the TCP/IP model has four or five layers depending on different preferences. Some vendors like to use the Application, Transport, Internet and Network Access layers.  However, a few people like to split the Network Access layer into the Physical and Data Link layers.

The Application Layer | Layer 4

The Application layer of the TCP/IP model is consider to be compatible with the application, presentation, and session layer of the OSI reference model. This layer gives facility to the applications for accessing the networking services. This is the fourth (4th) layer of TCP/IP model. It consists of high level protocols. This layer has ability to utilize both protocols TCP1 and UDP2 like TFTP3 uses UDP because usually on a LAN4 the physical links are sufficient small to make sure rapid and reliable packet transportation without most of errors. SMTP5 instead uses TCP due to error checking abilities.

The Transport Layer | Layer 3

The Transport layer is the third (3rd) layer of the TCP/IP model. It transports the services which being used by the application layer. The Transport layer is similar like the transport layer of the OSI reference model and performs the same functions, like it uses both TCP and UDP protocols. Error detection and recovery also process at this layer. The transport layer also uses checksums, acknowledgements, and timeouts for controlling transmissions and end to end assured delivery.  Unlike the OSI reference model, TCP/IP model handles reliability as end-to-end issues.

The Internet Layer | Layer 2

The Internet layer of the TCP/IP model performs the responsibilities as same like the Network layer of the OSI reference model. So, data delivery, key component of this architecture and routing is the main accountability of this layer. The Internet layer permits the transmission across the networks of multiple kinds and holds out translation to exchange with dissimilar data addressing schemes. This layer through packets on any network and destined them to the desired destination separately to one another. The packets may be received out of order due to the way through the network is not predestined. The recording of the data is the responsibility of the upper layers. It is the second (2nd) layer of the TCP/IP model. The internet layer’s main protocols are IP and ARP6 which most of being used at this layer.

Network Access Layer | Layer 1

The Network Access layer is the first (1st) layer of the Transmission Control Protocol/Internet Protocol (TCP/IP) model. The Data Link layer and the Physical layer of the Open System Interconnection (OSI) Reference model, which consists of real hardware, are combined in this layer. The Network Access layer contains of wires, network interface cards (NICs), other transmission media, connectors, wireless, signal strength, wavelength, etc. along with many others. This it utilize the desired LAN operating algorithms, such as Carrier Sense Multiple Access with Collision Detection (CSMA/CD)7 or IBM Token Passing8 etc. and data placement in a frame is also this layer’s cause. The frame format is dependent on the system being used, for example Ethernet LAN, Frame relay9, etc. The frame is the carries data, the hardware address of the host and checking algorithms for data integrity.

Terms for using TCP/IP Model:

  1. TCP (Transmission Control Protocol) – enables two to establish a connection and exchange streams of data.
  2. UDP (User Datagram Protocol) – offering a direct way to send and receive datagrams over an IP network with very few error recovery services.
  3. TFTP (Trivial File Transfer Protocol) – Simplified version of the FTP protocol which has no security features.
  4. LAN (Local Area Network) – A computer network that spans a small area.
  5. SMTP (Simple Mail Transfer Protocol) – Protocol used to send email messages between servers.
  6. ARP (Address Resolution Protocol) – used to convert an IP address to a physical address.
  7. CMSA/CD (Carrier Sense Multiple Access with Collision Detect) – protocol for carrier transmission access for Ethernet networks.
  8. IBM Token Passing – uses a token to grant a device the chance to transmit over the network.
  9. Frame Relay – a packet switching protocol for connecting devices on a Wide Area Network.

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