UNIT -2

TCP/IP (Transmission control protocol)/ (internet protocol)

Protocols – protocol mean the set of rules or standard design to enable computers to get connected with one another and exchange information with as little error as possible. The internet Protocol are a low level Protocol the rought Packets of data across separate networks tied together. Data travels in packets called IP data grams.

CP/ IP- TCP/IP is a communication protocol suite to used to inter connect network devices on the internet. TCP/ IP specifics how data is exchange over the internet by providing end to end communication. TCP/IP provides a solution to the problem of how two computers attach to the same intranet and how they can exchange data                                                                                                                               

TCP/ IP                                             TCP /IP

APPLICATION LAYER	APPLICATION LAYER
HOST TO HOST TRANSPOR LAYER	HOST TO HOST TRANSPOR LAYER
INTERNET LAYER	INTERNET LAYER
NETWORK INTERFACE LAYER	NETWORK INTERFACE LAYER

                                          

1)    Network Interface layer – Network Interface layer is the first layer of the four layers of TCP/IP model. This layer difference details of how data is physically sent throw the network, including how bits are physically signed by Hardware devices such as Coaxial Cable, Optical Fiber, Twisted pair copper wire. The Protocols included in this layer are Ethernet, token ring, FDDI, X Point 25, Frame Relay. The most popular LAN architecture among those is Ethernet.

2)    Internet layer – Internet Layer is the second layer of the four layers of TCP/IP model. The position of internet layer is between network access layer and Transport Layer. Internet Layer pack data into data packets known as IP data grams which contain source and destination address information i.e. use to forward the data grams between Host and across network is also responsible for routing. The main protocols included at internet layer are IP( Internet protocol) ,ICMP (Internet Control Massage Protocol ) , ARP( Address Resolution Protocol), RARP( Reverse Address Resolution Protocol) and IGMP( Internet Group Management Protocol).

3)    Transport Layer –Transport Layer is the 3^rd layer of the four layers of the TCP/IP model. The position of the Transport Layer between Application Layer and Internet Layer. The purpose of transport layer is to permit devices on the source and destination hosts to carry on a conversation. Transport layer defines the level of service and status of the connection used when transporting data. The main protocol included at transport layer are TCP and UDP (User Datagram Protocol).

4. Application Layer- Application Layer is the top most layer of the TCP/IP model Application Layer is present on the top of the Transport layer. Application layer define TCP/IP. Application protocols how host  Programs use the network. Application layer included all the higher level protocols like DNS( Domain Naming System) HTTP ( Hyper Text Transfer Protocol ) TELNET , SSH, FTP, TFTP, SNMP(Simple Network Management Protocol) SMTP (Simple Mail Transfer Protocol), DHCP ( Dynamic Host Configuration Protocol, RDP( Remote Desktop Protocol ) etc.

OSI (Open system Interconnection)	TCP/IP
1.    Application Layer	Application Layer	TELNET, FTP, SMTP,DNS,RIP,SNMP
2.    Presentation Layer	Application Layer	TELNET, FTP, SMTP,DNS,RIP,SNMP
3.    Session Layer	Application Layer	TELNET, FTP, SMTP,DNS,RIP,SNMP
4.    Transport Layer	Transport Layer	TCP/UDP
5.    Network Layer	Internet Layer	IP, IGMP, ASP
6.    Data Link Layer	Network Interface Layer	ETHERNET, Token ring, Frame ring, ATM
7. Physical Layer	Network Interface Layer	ETHERNET, Token ring, Frame ring, ATM

Ø The TCP/IP  model is not same as OSI model. OSI model is a seven layered model but TCP/IP /is a four layered model. The OSI model has been very influential in the growth and development of TCP/IP model, and i.e. way much OSI terminology is applied into the TCP/IP model.