TCP/IP Model-Data Communication

Detailed Explanation of TCP/IP Model

Layers in TCP/IP Model

The TCP/IP Model has four layers

1. Physical Layer and data link Layer
2. Network Layer
3. Transport Layer
4. Application Layer

1.Physical Layer and Data Link Layer

Physical and Data Link layer is combinedly known as host to network layer. They dose not define any protocols, but combindly supports all the standard protocols. Here LAN or WAN can be used as inter network.

2.Network Layer

In Network layer it supports inter  networking protocol known as IP. Inter networking protocol uses four different protocol internally, they are ARP, RARP, ICMP, IGMP.

Inter networking Protocol(IP)

It is used for data transmission. It transmit data in small packets known as data grams. Each of these data grams are transmitted separably so that they can take different routs to reach their destinations.

Address Resolution Protocol(ARP)

ARP is use to define the physical address of a device by using the IP address.

Reverse Address Resolution Protocol(RARP)

RARP is used to find tjr internet address of a device whose physical address is known.

Internet Control Message Protocol(ICMP) 

ICMP protocol is used as query and error reporting message. IP in network layer sends data in small packets known as data gram, if there is any problem in data grams then ICMP sends back these data grams to sender.

Internet Group Message Protocol(IGMP)

This protocol is use to send messages simultaneously to a group of recipients.

3.Transport Layer

Transport layer has three protocols, Transmission Control Protocol(TCP), User Data gram Protocol(UDP), Stream control Protocol(SCTP). These protocols are responsible for delivery of messages from one end to another.

User Data gram Protocol (UDP)

UDP is a process to process control protocol used for data transmission. it takes the data from upper layer of TCP/IP and add some information such as Port address, checksum, error control and length of the data. It finds the error in data transmission but it does not specify the error.

Transmission Control Protocol(TCP)

TCP is a connection oriented protocol. a connection must be made between sender and receiver before the data transmission. It divides the data into smaller units called segments. Each segments contains a sequence number which make it possible to rearrange in correct order at the receiver side. It also adds acknowledgment number to the segments to verify that the data is reached its actual destination or not. It does error control and specify the exact error.  

Stream Control Transmission Protocol(SCTP)

This protocol combines the best features of TCP and UDP.

4.Application Layer

Application layer is the top most layer of TCP/IP model. It is used for interconnection between user and application. There are several protocols used for user interaction such as HTTP, SNMP, SMTP, DNS, TELNET, FTP etc