Transmission Control Protocol/Internet Protocol (TCP/IP)

History of TCP / IP (Transmission Control Protocol / Internet Protocol) start of the birth of the ARPANET network digital switching package funded by DARPA (Defense Advanced Research Projects Agency) in 1969. TCP / IP is the standard communication data used by the community Internet in the process of exchange data from one computer to others in the Internet network.

Transmission Control Protocol/Internet Protocol (TCP/IP) be protocol exist in internet and world network. Protocol architecture model TCP/IP formed from 2 components that is Transmission Control Protocol (TCP) and internet protocol (IP). aim from TCP/IP build a connection delivers network (network), where  usually called internetwork, or internet, prepare communication service delivers network that has physical form various. clear aim connect owner (hosts) in different network, or may be dissociated geographically in area vast.

Internet can diversified to be several group network, among others:

1. backbone: big network that connects to deliver another network. example: nsfnet that be network backbone world at America, ebone be network backbone at europe, and another.
2. Regional network, example: network delivers campus.
3. Network has commercial where prepare connection aims backbone to the customer.
4. Local network, example: network in a campus.

Aspect other important from TCP/IP form a standardization in communication. 
every physical form a has technology that varies, so that need programming or special function to be used in communication. TCP/IP give special facilities on programming or special function from each physical network. so that architecture form from physical network disguised from user and network application maker. with TCP/IP, user not necessary again think network physical form to does a communication. To can identify host be need a address, called address IP (IP address). when a host has several network wares (interfaces), like router, so every interfaces must has a IP address unique. IP address consist from 2 parts, that is:

IP address = layer (layer) in protocol TCP/IP :
layer application is used in program to communicating to use TCP/IP. application example among others telnet and transfer file protocol (FTTP). interfaces that used to mutual communicating number port and socket. Layer transport give data delivery function according to end-to-end to side remote. application various can do communication according to together (simulaneously). protocol in layer transport most often used Transmission Control Protocol (TCP), where give data delivery function according to connection-oriented, data duplication prevention, congestion control and flow control. another protocol User Datagram Protocol (UDP), where give delivery function connectionless, stripe not reliabel. UDP many used in application that want speed tall towards data damage. Layer internetwork usually called also layer internet or layer network, where give “vitual network” in internet. Internet Protocol (IP) protocol most important. ip give function routing in network in data delivery. another protocol among others: ip, icmp, igmp, arp, rarp. Layer network interfaces is called also layer link or layer link data, be hardware in network.  example: IEEE 802.2, X.25, ATM, FDDI and SNA.

Excellence TCP / IP :

1. Open Protocol Standard.
2. Independent of the physical network hardware.
3. How to be unique in addressing the global scale.
4. TCP / IP routing facilities and the types of Other services that enable applied the internetwork.
5. High levels of standard protocols.

Open Systems Interconnection (OSI) model is a reference for understanding data communications between two interconnected systems. OSI layer divides the communication process into seven layers. Each layer functions to perform specific functions to support the layer above it and also offers a service to layer underneath. Three bottom layer will focus on traffic pass through the network to a final system. Four top layer will play the final system to complete the communication process.

Through this article we will understand each layer of the OSI seven layers, including the functions and relationships between these layers. This will give you a general overview of the network process, which could later become a framework for more detailed understanding of computer networks.

In addition, this article will also discuss about the comparison between the OSI model with its theoretical model of TCP / IP is functional in nature. Although TCP / IP is used in the communication network prior to the adoption of the OSI model, but the TCP / OP also supports the functions and features similar to the arrangement of different layers.

Architecture of TCP / IP :

Physical Layer.

Physical layer in the OSI model defines the connectors and interface specifications, and also needs the medium (cable). Specifications electrical, mechanical, functions and procedures provided for the delivery of a bit stream on a computer network.

Components of the physical layer of them is:

1. Network Interface Card (NIC).
2. Hubs, repeaters and patch panel specifications.
3. Components of the wireless system patch panel specifications.
4. Parallel SCSI (Small Computer System Interface).
5. Connector design and functions of each pin.
6. Media adapter that connects to the physical interface.
7. Wiring system components.

In the LAN environment, category 5e UTP cable (unshielded Twisted Pair) is usually used in physical layer to connect the individual devices. Wiring with fiber optic cable typically used in the physical layer in a vertical relationship or Riser backbone. Bodies such as the IEEE, EIA / TIA / ANSI and other standards bodies to make the standard for this layer.

Network Access Layer

Has a function similar to the Data Link layer in the OSI. These layers organize the data distribution of data frames on the physical media used reliable. This layer usually provides services for the detection and error correction of transmitted data. Some examples of protocols that used in this layer is X.25 public networks, Ethernet for networking 
Etehernet, network AX.25 Packet Radio etc.

Internet Layer

Defines how the relationship can occur between two parties who are on different networks such as the Network Layer of OSI. In the Internet network consisting of tens of millions of hosts and hundreds of thousands of local network, this layer served to ensure that a packet that is sent to find the goal wherever located. Therefore, this layer has a particularly important role in realizing internetworking covering vast areas (worldwide internet). Some of the important tasks in this layer are:

1. Addressing, which complement each datagram to the Internet address of the destination. Address of this protocol known as Internet Protocol Address (IP Address). Because addressing (addressing) the TCP / IP is at this level (software), then the TCP / IP network independent of the type of media and computer use.
2. Routing, which determines where the datagram will be sent in order to achieve the desired objectives. This function is the most important function of the Internet Protocol (IP). As the protocol is connectionless, the routing process is completely determined by the network. The sender has no control over the package he sent to reach the goal. Routers on a TCP / IP is a very decisive in delivering a datagram from the receiver to the destination.

Transport Layer
Defines the ways to perform data transmission between end-to-end in a reliable host. This layer ensures that the information received at the receiver side is the same as the information sent to the sender. Therefore, this layer has several important functions including:

1. Flow Control. Sending data that has been broken into these packages must be arranged in such a way that the sender not to send data at a speed that exceeds the ability of recipients to receive the data.
2. Error Detection. Sender and recipient also complement the data with some information that can be used to examine the data that is sent free of errors. If you found an error in the received data packet, then the recipient will not receive the data. The sender will resend the data packets that contain errors earlier. However, this can cause significant delays.

Application Layer
is the last layer in the architecture of TCP / IP that serves to define the applications that run on the network. Because of that, there are many protocols in this layer, according to the number of applications TCP / IP that can be run. Examples are SMTP (Simple Mail Transfer Protocol) for sending e-mail, FTP (File Transfer Protocol) to transfer files, HTTP (Hyper Text Transfer Protocol) for web applications, NNTP (Network News Transfer Protocol) for the distribution of news group and others. Each application generally uses TCP and IP protocols, so the whole family is named with the protocol TCP / IP.

    TCP/IP architecture

TCP is a protocol that allows application programs to access / use the communication services are connection-oriented. TCP able to provide service delivery reliable (reliable) both are flow-controlled.

TCP characteristics

Connection-oriented, That kind of service that require prior connection. Analogues such as when we call

Data transmission mechanism using connection-oriented service

Reliable

Reliable means that data is transferred to the destination in a sequence as when sent. Transport services on the Internet, a reliable delivery of a sequence of unicast model. Example: TCP.

Owned by the reliability of this protocol due to several mechanisms. The following mechanisms:

1. Checksum: all TCP segments carrying checksum will be used by the recipient (receiver device) to check whether any errors were errors in the data or the header of TCP itself.
2. Duplicate Data Detection: TCP's ability to maintain each byte is received for these bytes are not experiencing a doubling (read: received more than once).
3. Retransmisson: TCP's ability to implement the scheme for the repeated delivery of the shipment data broken or missing.
4. Sequencing: TCP's ability to develop data segments that have been received. This will create a TCP can send data back to an application with the correct order
5. Timers: TCP uses two timers at once in data transmission. Two of the timer timer timer static and dynamic. Protocol will wait for the sender of the recipient within a certain time period for an "Acknowledge". If the timer period has expired, the sender can send back (Retransmit) segment that will be sent.

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