TCP-IP MODEL IN DATA COMMUNICATION AND NETWORKING Akanksha Solanki1, Divya Sain2 Assistant Professor, S.B.C.E.T. Jaipur (INDIA )

ABSTRACT The protocol suite is also known as TCP/IP and used set of communication protocols in computer networking model. The Transmission Control Protocol (TCP) and the Internet Protocol (IP) was developed by defense advanced research projects agency (DARPA) of united state government by defense department. TCP/IP is network model and internet architecture works on TCP/IP m o d e l The functionality of IP suite is comprises into four layers. These layers are , transport (host –to- host layer), internet layer and network access layer and data moves from lowest to highest layer . The provides end-to-end data connectivity defining how data should be packetized, addressed, transfer, routed and received. Internet protocol is use for reliable data delivery and works with the Internet Protocol (IP) to safely send data from source to destination. TCP is responsible for controlling the size and rate of data exchange.OSI is a reference model and TCP/IP model, by comparing the functionality of each layer in both models. Keywords : TCP/IP, OSI, layers, protocols.

I. INTRODUCTION TCP/IP model is a layered achitecture.TCP/IP uses the client/server model of communication in which a computer user requests and is provided a service by another computer in the network. In TCP/IP model communication is primarily end-to-end, meaning each communication is from one end in the network to another end or host computer. In TCP/IP model the applications layer is the uppermost layer comprises of presentation, session and application layers of OSI model layers .It provides application related services which uses most common protocols like HTTP protocol also known as "stateless" protocol because each client request is considered a new request which is not related to any previous request. The (FTP), (Telnet) which is use for remote access , and the Simple Mail Transfer Protocol (SMTP) In second layer of TCP/IP model which is transmission control protocol(TCP) which is connection- oriented protocol and user datagram protocol (UDP)which is connectionless-oriented protocol, IGMP, ICMP protocol is used. In internet layer takes data from transport layer and passes it to most common protocol in this layer is IP (internet protocol) and IPSEC. In network interface layer similar to the and of OSI model. This layer deals with binary digits, packets are transmitted and routed over network and provide reliable communications. SLIP (Serial line internet protocol)_and PPP(point to point protocol) is used. Network interface layer includes LAN technologies such as Ethernet and Token ring and WAN technologies such as X.25 212 | P a g e

II. HISTORY OF TCP-IP The Tcp/Ip suite resulted from development and research conducted by th Defense Advanced Research Projects Agency (DARPA) in the year 1960. After initiating the pioneering ARPANET in 1969, DARPA ongoing work on a number of other data transmission technologies. In 1972, Robert E. Kahn tied the DARPA Information Processing Technology Office, where he started working on both satellite packet networks and ground-based radio packet networks, and renowned the value of being able to communicate crosswise both. In the spring of 1973, Vinton Cerf, the developer of the accessible ARPANET Network Control Program (NCP) protocol, joined Kahn to work on open-architecture interconnection models with the aim of designing the next protocol generation for the ARPANET [3]. In the summer of 1973, Kahn and Cerf had worked out a primary reformulation, in which the differences between network protocols were concealed by using a common internetwork protocol, and, in its place the network being responsible for dependability, as in the ARPANET, the hosts became responsible. Cerf credits Hubert Zimmermann and Louis Paulin, designer of the CYCLADES network, with important influences on this design. The design of the network included the recognition that it should make available only the functions of efficiently transmitting and routing traffic amid end nodes and that all other intelligence should be located at the edge of the network, in the end nodes. Using a simple design, it became probable to connect almost any network to the ARPANET, irrespective of the local distinctiveness, thereby solving Kahn's initial problem. A computer called a router is a networking device or software act as a dispatcher which forwards packets from one network to another. It will also choose the best route for fast data delivery originally a router was called gateway, but the term was changed to avoid confusion with other types of gateway.

III. LAYERS OF TCP-IP MODEL The TCP/IP suite is a conceptual model based on layered architecture. it provide end-to-end communication and map into four abstracted layers namely application layer, transport layer ,internet layer and network interface layer from lowest to highest .it uses a set of protocol for communication across different networks. 1. Application Layer: Application layer is the top most layer of TCP/IP model. It provides services to connect application programs to communications protocols and to make sure efficient communication with other application programs across networks. It is comprises of application, presentation and session layers of OSI model. Some common TCP/IP applications services include: Telnet Protocol  File Transfer Protocol (FTP)  Hyper text transfer protocol (HTTP)  Simple Mail Transfer Protocol (SMTP)  Dynamic Host Configuration Protocol (DHCP)  Domain Name System (DNS)

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 Network Information Service (NIS)  Network File System (NFS)  Secure shell (SSH)  Secure copy (SCP)  Socks4 2.Transport Layer: the transport layer is responsible for host –to –host communication. Transport Layer manages connection oriented streams, flow control, reliable communication and multiplexing. The main protocols of transport layer are TCP, UDP and SCTP.

IV. Transmission Control Protocol (TCP) TCP handles the communication of the data coming from the Application Layer and transfer it to the next layer.TCP is connection-oriented protocol means that prior to transmission end points need to be connected first. TCP protocol data units (PDU) are called segments. The transmission of data between sending and receiving entities in the form of segments, which consist of a fixed 20-byte header that followed by a variable size data field. TCP divides a stream of bytes into segments and rejoining them at the other side; it also takes cares of retransmitting of lost segments and also organizing the segments in the exact order. ]

V. User Datagram Protocol (UDP) UDP is connectionless-oriented protocol without the guarantee of delivery. UDP takes less overhead of acknowledgments of packet receipt, retransmission of data and sequence of packet ordering. UDP is faster than TCP, but in UDP data can definitely be lost. UDP is more useful in multicasting data such as streaming video. If packets are lost or not in order, then missing packets are dropped. Because lost packets may be seem jumpy.

VI. STREAM Control Transmission Protocol (SCTP) SCTP was originally defined in RFC 2960 in October 2000, but was then updated with RFC 4960 in September 2007.SCTP is a protocol which can send multiple streams of data between two end points at the same time. SCTP is message oriented protocol, reliable protocol that combines best features of TCP and UDP. SCTP have a feature of multi homing that means joined end point can have different IP address associated with it in order to route around network failure or varying conditions.

VII. INTERNET LAYER Internet layer is responsible of for end to end delivery of packets and for rounding the packets through the routers or switches. It takes data from transport layer and passes it to network interface layer. It also contains the IP header on the packets with logical address of source and destination. The internet layer has three basic functions:  Transmitting data grams to the Network Interface layer. 214 | P a g e

 Routing of diagrams to the exact destination. Internet layer takes care of transfer the data through the shortest route if multiple routes are exists. In addition, if any problem occurs on the route through which a datagram is to be sent, then alternate routes are used for datagram delivery.  Errors handling and fragmentation and reassembling of packets. The core protocols for the IPv4 Internet layer consist of the following: 7.1 The Address Resolution Protocol (Arp) resolves the logical address to a physical address such as a hardware address. The Address Resolution Protocol (ARP) abstractly exists between the data-link layer and Internet layers. ARP assists IP in directing diagrams to the appropriate receiving system by mapping Ethernet addresses (48 bits long) to known IP addresses (32 bits long). The IP protocol The Internet Protocol (IP) is a data oriented protocol and it is used for data communication across a network. It is a best effort protocol means it does not guarantee of data delivery and correctness of data. IP is responsible for the following:  IP addressing  Host-to-host communications  Packet formatting  Fragmentation

7.2 The Internet Control Message Protocol: (ICMP) identifies errors and other information to help you identify failed packet delivery. The Internet Control Message Protocol (ICMP) detects and reports network

error conditions. ICMP reports on the followingDropped packets

 Connectivity failure  Redirection

 The Internet Group Management Protocol (IGMP) manages IP multicast groups.

7.3 Network Interface Layer: Network interface Layer is the lowest layer of TCP/IP model. This layer is comprises of the Data Link and Physical layers of the OSI model .this layer is responsible of how data is physically transmitted through communication channels such as co-axial,fibre optical cable etc over networks. it provide reliable communication between hosts on a network. It provides following services:

 Data Framing - Breaking up the large data stream into separate frames or packets.  Checksums - sending checksum data for each frame to allow the receiving node to find out the receiving frames are error free or not  Acknowledgment – it provides the acknowledgment the weather the data received or not .

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 Flow Control – data buffering transmissions to make sure that a fast sender does not overpower a slower receiver.

Network access Layer describes the standards for physical media and electrical signaling throughout communication process. These standards are Ethernet, Token Ring FDDI and frame Relay. Network Access Layer protocols are Ethernet, Token Ring, FDDI, X.25, Frame Relay etc. Ethernet uses an Access Method known as CSMA/CD (Carrier Sense Multiple Access/Collision Detection) to access the media,

Figure.1

OSI VS TCP/IP Model OSI(Open System Interconnection) TCP/IP(Transmission Control Protocol / Internet Protocol)

1. OSI is a generic, protocol independent 1. TCP/IP model is based on standard protocols around standard, acting as a communication gateway which the Internet has developed. It is a communication between the network and end user. protocol, which allows connection of hosts over a network.

2. In OSI model the transport layer guarantees 2. In TCP/IP model the transport layer does not guarantees the delivery of packets. delivery of packets. Still the TCP/IP model is more reliable.

3. Follows vertical approach. 3. Follows horizontal approach.

4. OSI model has a separate Presentation layer 4. TCP/IP does not have a separate Presentation layer or

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and Session layer. Session layer.

5. OSI is a reference model around which the 5. TCP/IP model is, in a way implementation of the OSI networks are built. Generally it is used as a model. guidance tool.

6. Network layer of OSI model provides both 6. The Network layer in TCP/IP model provides connection oriented and connectionless service. connectionless service.

7. OSI model has a problem of fitting the 7. TCP/IP model does not fit any protocol protocols into the model.

8. Protocols are hidden in OSI model and are 8. In TCP/IP replacing protocol is not easy. easily replaced as the technology changes.

9. OSI model defines services, interfaces and protocols very clearly and makes clear 9. In TCP/IP, services, interfaces and protocols are not distinction between them. It is protocol clearly separated. It is also protocol dependent. independent.

10. It has 7 layers 10. It has 4 layers

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Diagrammatic Comparison between OSI Reference Model and TCP/IP Reference Model

Figure. 2

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CONCLUSION

In this paper we tried to explain the basic reference models TCP/IP reference model. TCP/IP suite defines layer more based on protocols. Due to increase in protocols a model came into existence to explain these protocols which is TCP/IP model. Improvement is done in this model with time as new technologies are developing. In this paper we also tried to differentiate between OSI and TCO/IP model. We can’t really refuse any one of these models as both of these are equally important and widely use all over the world.

REFRENCES

[1] Behrouz A. Forouza,, Data Communications and Networking, 2003 [2] Margaret Rouse, “OSI (Open Systems Interconnection)”,in http://searchnetworking.techtarget.com/definition/OSI. [3] http://en.wikipedia.org/wiki/Internet_protocol_suite [4] http://en.wikipedia.org/wiki/OSI_model [5] http://www.exa.unicen.edu.ar/catedras/comdat1/material/TP1-Ejercicio5-ingles.pdf [6] “OSI” http://www.webopedia.com/TERM/O/OSI.html (15Mar. 2002). [7] http://www.studytonight.com 219 | P a g e

[8] https://technet.microsoft.com [9] https://docs.oracle.com [10]http://www.omnisecu.com/tcpip/osi-model.php [11] Bradley Michell(http://compnetworking.about.com/cs/designosimodel/a/osimodel.htm) [12]http://computer.howstuffworks.com/osi.html [13] TCP/IP Illustrated: the protocols, ISBN 0-201-63346-9, W. Richard Stevens, February 1994 [14]William Stallings, Data and Computer Communications, Prentice Hall 2006, ISBN 0-13-243310-9 [15]“Information processing systems -- Open Systems Interconnection -- Basic Reference Model -- Part 4: Management framework”

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