TCP/IP Protocol

 TCP/IP Protocol in detail

• TCP/IP protocol suite, often known as Internet suite, is used on the Internet. This is the definition of the Internet Model, which has a four-layered design. 
• The TCP/IP model came first, followed by the OSI model.
• The TCP/IP model and the OSI model are not identical.
• The application layer, transport layer, network layer, data link layer, and physical layer are the five layers of the TCP/IP paradigm.
• The first four levels, which correspond to the first four layers of the OSI model, include physical standards, network interface, internetworking, and transport services, and these four layers are represented in the TCP/IP paradigm by a single layer termed the application layer.
• TCP/IP is a hierarchical protocol made up of interacting modules, each of which has its own set of features.
• TCP/IP layers have the following functions: The OSI Model is a broad communication paradigm, whereas the Internet Model is the model used by the internet for all communication. 
• The internet, like its underlying network architecture, is self-contained.

This model has the following layers:

TCP/IP Protocol

Network Access Layer

• The TCP/IP model's lowest layer is the network layer.
• The OSI reference model defines a network layer as a mix of the Physical and Data Link layers.
• It specifies how data should be physically sent through the network.
• This layer is primarily in charge of data transfer between two devices on the same network.
• Encapsulating IP datagrams into network frames and translating IP addresses to physical addresses are two of the services performed by this layer.
• Ethernet, token ring, FDDI, X.25, and frame relay are the protocols used by this layer.

Internet Protocol Layer

• The second tier of the TCP/IP paradigm is the internet layer.
• The network layer is another name for the internet layer.
• The internet layer's primary function is to transmit packets from any network to their destination, regardless of the route they take.

The protocols used at this layer are as follows:

IP Protocol: 

• This layer employs the IP protocol, which is the most important component of the TCP/IP suite.

This protocol's duties are as follows:

• IP Addressing: This protocol implements IP addresses, which are logical host addresses. The internet and higher layers employ IP addresses to identify devices and to enable internetwork routing.
• Communication between hosts: It specifies how the data will be conveyed.
• Data Encapsulation and Formatting: The data from the transport layer protocol is accepted by an IP protocol. An IP protocol wraps data into a message known as an IP datagram and guarantees that it is transferred and received securely.
• Fragmentation and Reassembly: The Maximum Transmission Unit (MTU) is the size restriction set by the data link layer protocol on the size of an IP datagram (MTU). If the size of an IP datagram exceeds the MTU unit, the IP protocol divides the datagram into smaller units for transmission across the local network. The sender or an intermediary router might fragment data. All of the pieces are reconstructed at the receiver's end to make an original message.
• Routing: Direct delivery occurs when an IP datagram is transferred via the same local network, such as a LAN, MAN, or WAN. The IP datagram is transferred indirectly when the source and destination are on a different network. The IP datagram can be routed through multiple devices, such as routers, to do this.

ARP Protocol 

• Address Resolution Protocol (ARP) is an acronym for Address Resolution Protocol.
• ARP is a network layer mechanism for determining a physical address based on an IP address.
• The ARP Protocol is mostly connected with the two terms:

1. Request for an ARP: When a sender needs to know the device's physical address, it sends an ARP request to the network.
2. ARP's response: Every network device will receive and execute the ARP request, but only the recipient will identify the IP address and respond with its physical address in the form of an ARP reply. The physical address is added to the recipient's cache memory as well as the datagram header.

The ICMP Protocol

• The Internet Control Message Protocol (ICMP) stands for Internet Control Message Protocol.
• It is a method used by hosts or routers to communicate back to the sender notifications about datagram errors.
• Until it reaches its destination, a datagram goes from router to router. 
• The ICMP protocol is used to alert the sender that the datagram is undeliverable if a router is unable to route the data due to unexpected situations such as disabled connections, a device on fire, or network congestion.

The most common words used in an ICMP protocol are:

ICMP Test: 

• The ICMP Test is used to determine whether or not a destination can be reached.

ICMP Reply: 

• ICMP Reply is used to check whether the destination device is responding or not.
• The ICMP protocol's primary function is to notify issues rather than to solve them. The sender bears responsible for the adjustment.
• Because the IP datagram includes the addresses of the source and destination but not of the router to which it is sent, ICMP can only transmit messages to the source and not to intermediate routers.

Transport Layer

• The transport layer is in charge of data dependability, flow control, and correction as it travels through the network.
• User Datagram Protocol and Transmission Control Protocol are the two protocols utilized at the transport layer.

UDP(User Datagram Protocol)

• It delivers a connectionless service as well as end-to-end transmission delivery.
• It's a shaky protocol since it detects mistakes but doesn't tell you what they are.
• The problem is discovered by the User Datagram Protocol, and the ICMP protocol informs the sender that the user datagram has been corrupted.

The fields in UDP are as follows:

Source Port Address: The address of the application software that produced the message is known as the source port address.

Destination Port Address: The address of the application software that receives the message is known as the destination port address.

Total length: It defines the total number of bytes of the user datagram in bytes.

Checksum: The checksum is a 16-bit field that is used to detect errors. 

The loss of a packet is not specified by UDP. UDP simply includes a checksum; it does not contain a data segment ID.

UDP

Transmission Control Protocol (TCP)

• It provides apps with full transport layer services.
• It establishes a virtual circuit between the sender and the receiver, which remains active throughout the communication.
• TCP is a dependable protocol since it detects errors and retransmits the frames that have been damaged. 
• As a result, before the transmission is considered complete and a virtual circuit is deleted, all segments must be received and acknowledged.
• TCP breaks the entire message into smaller units known as segments at the sending end, and each segment contains a sequence number that is used to reorder the frames to form the original message.
• TCP takes all segments and reorders them depending on sequence numbers at the receiving end.

Application Layer

• In the TCP/IP model, the application layer is the topmost layer.
• It is in charge of high-level protocols and representational concerns.
• The user can interact with the application through this layer.
• When one application layer protocol wishes to connect with another, it sends its information to the transport layer.
• In the application layer, there is some ambiguity. Except for those that interface with the communication system, no application can be deployed inside the application layer. 
• For instance, a text editor cannot be regarded an application layer protocol but a web browser interacts with the network via the HTTP protocol, which is an application layer protocol.

Following are the main protocols used in the application layer:

HTTP: 

• HTTP stands for Hypertext Transfer Protocol. 
• This protocol enables us to access data via the internet. It sends data in plain text, audio, and video formats. 
• It's called a hypertext transfer protocol because it's efficient enough to utilize in a hypertext context with frequent jumps from one document to the next.

SNMP: 

• SNMP stands for Simple Network Management Protocol. It is a framework that uses the TCP/IP protocol stack to manage devices over the internet.

SMTP: 

• Simple mail transfer protocol (SMTP) is an acronym for Simple mail transfer protocol. 
• The TCP/IP protocol that handles e-mail is called Simple Mail Transfer Protocol (SMTP). This protocol is used to send data to another e-mail address.

DNS: 

• DNS stands for Domain Name System. An IP address is used to uniquely identify a host's internet connection. People, on the other hand, prefer to utilize names rather than addresses. 
• As a result, the Domain Name System is the system that translates the name to the address.

TELNET: 

• TELNET stands for Terminal Network and is an abbreviation for it. 
• It establishes a connection between the local and remote computers in such a way that the local terminal seems to be a remote terminal.

FTP: 

• FTP stands for File Transfer Protocol. FTP (File Transfer Protocol) is a standard internet protocol for transferring data from one computer to another.