Explain the TCP/IP Reference Model with diagram

The TCP/IP reference model is the network model used in the current Internet architecture. It is considered as the grandfather of the Internet the ARPANET. The reference model was named after two of its main protocols, TCP (Transmission control Protocol) and IP(Internet Protocol).

There are versions of this model with four layers and with five layers. The original four-layer version of the model is shown below.

Ø Layer 4: Process Layer or Application Layer: This is where the “higher level” protocols such as FTP, HTTP, etc. operate. The original TCP/IP specification described a number of different applications that fit into the top layer of the protocol stack. These applications include Telnet, FTP, SMTP and DNS.

Ø Layer 3: Host-To-Host (Transport) Layer: This is where flow-control and connection protocols exist,, such as TCP. This layer deals with opening and maintaining connection, ensuring that packet are in fact received the transport layer is the interface between the application layer and the complex hardware of the. Two modes are available, full-duplex and half duplex. In full-duplex operation, both sides can transmit and receive data simultaneously, whereas in half duplex, a side can only send or receive at one time.

Ø Layer 2: Internet or Internetworking Layer: This layer defines IP addresses, with many routing schemes for navigating packets from one IP address to another. The job of the network layer is to inject packets into any network and have them travel independently to the destination. Packet routing is a major job of this protocol.

Layer 1: Networking Access Layer: This layer describes the physical equipment necessary for communications, such as twisted pair cables, the signalling used on that equipment, and the low-level protocols using that signalling. That Host-to-Network layer interfaces the TCP/IP protocol stack to the physical network.