The open system interconnection (OSI) model defines a networking frame to implement protocols in seven layers. Use this helpful guide to distinguish other layer of the OSI model and understand how they interact with each other. The history of growth of the OSI model is, for some excuse, a little known story, most of the work of OSI made by honeywell, with expert product planning and the desaign and growth of prototype systems. OSI works by sending data from top layer necessarily to be passed down and in input the capacity of a PDU in bottom layer. In the real world, the process of encapsulation (adding a header ) doesn't always occur at all layers and sometimes things get chopped into smaller pieces so they will be easier to send and receive . OSI layer is created by the OSI in 1970 as it was before OSI protocols that there is a named Dod but only used by government departments of defences. Then OSI model has seven layers with the bottom layer of the sequence is the physical, data link, network, transport, session, presentation and user application .
Definition of the OSI model is a network device used to implement protocols in seven layers. The control usage is passed from one layer to the next.
History of OSI is initiated at the end of 1970’s, two projects started independently, with the same purpose to define standards. The network system architecture is given by the international organization for standardization (ISO), while others are conducted by international telegraph and telephone consultations Steering Comittee, or CCIT (the abbreviation of the French version) .These two international standards bodies were each developed a document that defined the same model network . In 1983 the two documents are merged to form a so-called standard model of elementary reference to standard OSI usually referred to a model OSI reference, the OSI reference model or models of OSI are only published in 1984 by the ISO, as standard ISO 7498 and renamed CCITT (or now called the telecommunication standardization sector of international telecommunication union or ITU-T) as standard x 200.
The work method of the OSI is started from the top layer should be lowered and put into a payload of the PDU to the layer below it, in the real world, the process of encapsulation (add header) does not always occurs in all walks of life and sometimes things that can be cut into small so they will be easier to sent and receiving data passes through the internet, so it gets the first header of the application, then on the Transmission Control Protocol (TCP), the Internet Protocol (IP) to add headers and shared to the physical connection.
The difference between OSI and DOD is the layers. DOD has only 4 layers but DOD models also have the same functionality as the OSI session layer. DOD is combining and presentating layer in the OSI application layer while to differentiate into specific layers.
The main purpose of usage of the OSI model is to help network designers understand the function of each layer associated with the flow of data communication. The bottom layer is the physical layer that used to define the network transmission medium, signaling method, bit synchronization, network architecture, network topology and cabling. The next layer is the data link layer that used to determine how the data bits are grouped to format called frames. Data link layer after that layer is a layer that used in Networking to define IP addresses, create a header for packets, and perform routing through internetworking with using routers and layer 3 switches Networking layer. The next layer is the transport layer that serves to break down the data into the data packets and provide the serial number to those packages that can be rearranged on the side of the goal after receipt. Then the next layer is the Session layer which serves to define how the connection can be made, kept, or destroyed. Then the next layer is the presentation layer that serves to translate the data to be transmitted by the application into a format that can be transmitted over the network. Then the last layer is the application layer which serves to explain specifically to the scope in which network applications communicate with network services and provide services for the user application or can be used to interface with applications to network functionality, set how applications can access the network and create error messages .
In general, the protocol has a function to connect the receiver side and to communicate and exchange information in shipping, OSI Data send it step by step depending the sequence 7 layers exist.
Rabu, 06 Mei 2015
The Evolution of Mobile Technology
Early discovery of radio transmission is initiated by Guglielmo Marconi in 1901 which became the basis of mobile technology. Guglielmo Marconi is inspired by Clark Maxwell theory of electromagnetic radiation.After several years of research finally the first precursors introduced. In the years 1940s in Europe. This is the beginning of the development of mobile technology. until now, the development of technology is growing very rapidly.
The launch of the first generation of mobile technology was carried out in 1970s. First system of 1G used an analog system. This system is the basis of new technology for the world’s telecommunications. There are several standart of 1G system. Such as Advanced Mobile Phone System (AMPS) which is used in the United State. Nordic Mobile Telephone (NMT) used in Nordic countries (Denmark, Finland, Iceland, Norway, and sweden) There are also Total Access Communication System (TACS) this system used in United Kingdom.
After 20 years of using 1G finally 2G discovered in 1990s. 2G is usually refered to as global system for mobile communication. 2G have excellence service that quite a lot compare with the previous network such as paging, faxing, and voice mailing.2G network also has quite a lot of data services such as WAP, HSCSD and MLS. Benefits 2G is very useful at the moment, because the technology can reduce noise. In other words the user’s voice can be clearly heard. 2G also provide extra security, because data has been shaped digital encryption.
After the second generation was found in the early 1990s, finally the next generation 2G network is 2,5G found at the end of 1990s. This generation used standart GPRS system (general Packet Radio Service). The system can increase the data capacity because of the higher data capacity of the graphic delivery can be done. With the discovery of 2,5G packet switch data (IP) can be applied. this is the beginning of the development of mobile internet technology.
After several years of research, finally the 3G network be discovered 3G adapted from some previous discovery. 3G network used GPRS (general Packet Radio Service) system that has been perfected. On the previous network standart IP not yet determined, then in this 3G system IP began standardized globally. Benefit of 3G very much, because 3G network have suficent bandwidth. So many features that we can use as a video call, streaming, and many more. With the advantages provided by a 3G network, the world community is now using 3G network to communicate.
After success of 3G networks in telecommunications, network researchers didn’t stop developing better and faster. With the demands of fast data speeds and efficient. Eventually researchers can develop a better network, that is 4G / LTE and more proud of is the inventor of 4G is Indonesian. with the 4G network, the potential applications that can be used more. Such as video conferencing in high definition. Speed of 4G is very fast some of the companies trying 4G mobile communication at 100 Mbps for mobile users and up to 1 Gbps over fixed stations.
The development of mobile technology from year to year continues to progress in the field of telecommunications. Let us together build a network. so that people can communicate more smooth and comfortable. because in the future, the speed of information is needed.
The launch of the first generation of mobile technology was carried out in 1970s. First system of 1G used an analog system. This system is the basis of new technology for the world’s telecommunications. There are several standart of 1G system. Such as Advanced Mobile Phone System (AMPS) which is used in the United State. Nordic Mobile Telephone (NMT) used in Nordic countries (Denmark, Finland, Iceland, Norway, and sweden) There are also Total Access Communication System (TACS) this system used in United Kingdom.
After 20 years of using 1G finally 2G discovered in 1990s. 2G is usually refered to as global system for mobile communication. 2G have excellence service that quite a lot compare with the previous network such as paging, faxing, and voice mailing.2G network also has quite a lot of data services such as WAP, HSCSD and MLS. Benefits 2G is very useful at the moment, because the technology can reduce noise. In other words the user’s voice can be clearly heard. 2G also provide extra security, because data has been shaped digital encryption.
After the second generation was found in the early 1990s, finally the next generation 2G network is 2,5G found at the end of 1990s. This generation used standart GPRS system (general Packet Radio Service). The system can increase the data capacity because of the higher data capacity of the graphic delivery can be done. With the discovery of 2,5G packet switch data (IP) can be applied. this is the beginning of the development of mobile internet technology.
After several years of research, finally the 3G network be discovered 3G adapted from some previous discovery. 3G network used GPRS (general Packet Radio Service) system that has been perfected. On the previous network standart IP not yet determined, then in this 3G system IP began standardized globally. Benefit of 3G very much, because 3G network have suficent bandwidth. So many features that we can use as a video call, streaming, and many more. With the advantages provided by a 3G network, the world community is now using 3G network to communicate.
After success of 3G networks in telecommunications, network researchers didn’t stop developing better and faster. With the demands of fast data speeds and efficient. Eventually researchers can develop a better network, that is 4G / LTE and more proud of is the inventor of 4G is Indonesian. with the 4G network, the potential applications that can be used more. Such as video conferencing in high definition. Speed of 4G is very fast some of the companies trying 4G mobile communication at 100 Mbps for mobile users and up to 1 Gbps over fixed stations.
The development of mobile technology from year to year continues to progress in the field of telecommunications. Let us together build a network. so that people can communicate more smooth and comfortable. because in the future, the speed of information is needed.
The Functions and Types of Antenna
An electrical device which has power to changes become radio waves and vice versa is called antenna. There are some different kinds of antenna that belonged in three groups. There are omni-directional, directional, and semi-directional that propagates in different directions. Because of the different groups, there are many types of antennas for example dipole antenna, directional antenna, micro-strip antenna, sector antenna, yagi antenna, parabolic antenna, and grid antenna.
One of the types of antenna is dipole antennas. Dipole antennas usually called rubber ducky, are antennas that belonged in omni-directional groups. Dipole antennas have characteristic that are propagate radio frequency (RF) energy in 360 degrees with horizontal direction. Dipole antenna has forms very easy to build. It consists of two slice of wire-cut to the proper length or can be encapsulated. The function of dipole antennas are usually implementated in many enterprise and home production.
Directional and semi-directional groups are antennas that focus to radiate power into tight beams. The common characteristic of directional and semi-directional antennas are reciprocal, and in the transmitting antenna used in receiving antenna. The directional and semi-directional antennas are used in long distance like satellite.
A patch antenna is including in a semi-directional antenna group. This antenna also famous as micro-strip antenna. And the characteristic of this antenna is commonly rectangular and enclosed in a plastic enclosure, beam-width of patch antenna approximately 30 until 190 degrees and the common gain is 9 dB. One of another semi-directional antenna group is sector antennas. Sector antennas have characteristic namely sector antenna supply a pie-form or sector radiation pattern and are commonly set a sectorized array, beam-width of sector antenna approximately 60 until 180 degrees but commonly 120 degrees. The implementation of sector antennas is usually used in cellular communication.
One of directional antenna type is yagi antenna. To form a directional array, yagi antenna uses several elements. The signs of yagi antenna consist of single driven element in-circuit transmitter or receiver with a transmission line and additional parasitic elements, yagi antenna also has beam-width between 30 to 80 degrees, and supply excess of 10 dB passive again. Yagi antenna is usually used in fixed-frequency applications, like as rooftop terrestrial television antenna, radio amateurs, and broadcasting stations.
The most famous type of directional antenna is parabolic antenna or usually called as dish antenna. The characteristic of this antenna is using a parabolic reflector, a curved surface with the cross-sectional form a parabola, to direct the radio waves. High directivity is one of the advantage parabolic antennas. And another characteristic parabolic antenna is narrow beam-width, commonly not exceeding 25 degrees. Implementations of parabolic antenna are microwave relay links which carry telephone and television signals range nearby cities, wireless WAN or LAN links for data communications, satellite communications, spacecraft communication antenna, and radio telescopes. Variation of the dish is called grid antenna. Grid antenna belongs to directional antenna. A parabolic reflector will give a large solid surface to the wind. The wind condition can be high or moderate will cause the dish deform. To prevent this condition, the reflector perforated becomes a grid. The characteristic grid antenna such as beam-width and gain are as same as with parabolic antenna.
Based on three groups of antennas, the application of antennas varies according the characteristics and function antennas.
One of the types of antenna is dipole antennas. Dipole antennas usually called rubber ducky, are antennas that belonged in omni-directional groups. Dipole antennas have characteristic that are propagate radio frequency (RF) energy in 360 degrees with horizontal direction. Dipole antenna has forms very easy to build. It consists of two slice of wire-cut to the proper length or can be encapsulated. The function of dipole antennas are usually implementated in many enterprise and home production.
Directional and semi-directional groups are antennas that focus to radiate power into tight beams. The common characteristic of directional and semi-directional antennas are reciprocal, and in the transmitting antenna used in receiving antenna. The directional and semi-directional antennas are used in long distance like satellite.
A patch antenna is including in a semi-directional antenna group. This antenna also famous as micro-strip antenna. And the characteristic of this antenna is commonly rectangular and enclosed in a plastic enclosure, beam-width of patch antenna approximately 30 until 190 degrees and the common gain is 9 dB. One of another semi-directional antenna group is sector antennas. Sector antennas have characteristic namely sector antenna supply a pie-form or sector radiation pattern and are commonly set a sectorized array, beam-width of sector antenna approximately 60 until 180 degrees but commonly 120 degrees. The implementation of sector antennas is usually used in cellular communication.
One of directional antenna type is yagi antenna. To form a directional array, yagi antenna uses several elements. The signs of yagi antenna consist of single driven element in-circuit transmitter or receiver with a transmission line and additional parasitic elements, yagi antenna also has beam-width between 30 to 80 degrees, and supply excess of 10 dB passive again. Yagi antenna is usually used in fixed-frequency applications, like as rooftop terrestrial television antenna, radio amateurs, and broadcasting stations.
The most famous type of directional antenna is parabolic antenna or usually called as dish antenna. The characteristic of this antenna is using a parabolic reflector, a curved surface with the cross-sectional form a parabola, to direct the radio waves. High directivity is one of the advantage parabolic antennas. And another characteristic parabolic antenna is narrow beam-width, commonly not exceeding 25 degrees. Implementations of parabolic antenna are microwave relay links which carry telephone and television signals range nearby cities, wireless WAN or LAN links for data communications, satellite communications, spacecraft communication antenna, and radio telescopes. Variation of the dish is called grid antenna. Grid antenna belongs to directional antenna. A parabolic reflector will give a large solid surface to the wind. The wind condition can be high or moderate will cause the dish deform. To prevent this condition, the reflector perforated becomes a grid. The characteristic grid antenna such as beam-width and gain are as same as with parabolic antenna.
Based on three groups of antennas, the application of antennas varies according the characteristics and function antennas.
The use of Satellite in Telecommunication
In telecommunication, artificial satellite is used to provide link communication between point with other point on the earth. There are communication satellite playing important role in the global telecommunications system. Approximately 2000 artificial satellite orbit earth conveying analog and digital signals that bring voice, video, and data to and from one or many locations worldwide. An artificial telecommunication is a man made object placed into orbit in earth for the purpose of scientific research, weather reports, or military reconnaissance. Nowdays satellite are extremely important today. An artificial telecommunication has many application in earth.
1. astronomical satellites
These satellites are usefull for the observation of distant stars and other objects in space.
Generally monitoring point in a placed on mountain altitude experience low levels of cloud, because unwanted effect ot the atmosphore and enables bigger levels of detail to be seen. The most popular astronomical satellite is the Hubble Telescope. However it suffers some design setback that were only found once it was in orbit.
2. Communication satellites
These satellite are a possible form that have the bigger number of satellites in orbit. They are used for communicating over long distance. The altitude of satellite that on the earth enables the satellite communicate with above wide distances. Thereby cope with the curvature of the Earth’s surface. usually finding is use communications satellite such mobile communications, and some are used for direct broadcast.
3. Earth observation satellites
These satellites are useful for monitoring the earth’s surface and usually they are often name geographical satellites. Purpose from satellites it is possible to look many condition that are not obvious in the earth’s surface or look existence at altitudes at which aircraft .
4. Navigation satellites
These satellite recent in years is usefull for accurate navigation be said to be GPS. The first system known as GPS (Global Positioning System) was set up by the US DoD and was primarily purpose for use as a highly accurate military system. System GPS (Global Positioning System) is an tool that use for quest for an place that want destination.
5. Reconnaissance satellites and Weather satellites
Reconnaissance satellites are usefull for looking object on the ground and according used for military purposes. As such exhibition and operation are kept secret and not publicized. Weather satellites is a latest application of satellite. It used to observe the weather, they always monitoring assignment areas in earth and portended the weather conditions of that regions. This is done by taking object of earth from satellite.
There many satellites artificial satellite that orbit earth conveying analog and digital signals that bring voice, video, and data to and from one or many locations worldwide. Each and every artificial satellite have purpose such as reconnaissance, see weather at earth.
1. astronomical satellites
These satellites are usefull for the observation of distant stars and other objects in space.
Generally monitoring point in a placed on mountain altitude experience low levels of cloud, because unwanted effect ot the atmosphore and enables bigger levels of detail to be seen. The most popular astronomical satellite is the Hubble Telescope. However it suffers some design setback that were only found once it was in orbit.
2. Communication satellites
These satellite are a possible form that have the bigger number of satellites in orbit. They are used for communicating over long distance. The altitude of satellite that on the earth enables the satellite communicate with above wide distances. Thereby cope with the curvature of the Earth’s surface. usually finding is use communications satellite such mobile communications, and some are used for direct broadcast.
3. Earth observation satellites
These satellites are useful for monitoring the earth’s surface and usually they are often name geographical satellites. Purpose from satellites it is possible to look many condition that are not obvious in the earth’s surface or look existence at altitudes at which aircraft .
4. Navigation satellites
These satellite recent in years is usefull for accurate navigation be said to be GPS. The first system known as GPS (Global Positioning System) was set up by the US DoD and was primarily purpose for use as a highly accurate military system. System GPS (Global Positioning System) is an tool that use for quest for an place that want destination.
5. Reconnaissance satellites and Weather satellites
Reconnaissance satellites are usefull for looking object on the ground and according used for military purposes. As such exhibition and operation are kept secret and not publicized. Weather satellites is a latest application of satellite. It used to observe the weather, they always monitoring assignment areas in earth and portended the weather conditions of that regions. This is done by taking object of earth from satellite.
There many satellites artificial satellite that orbit earth conveying analog and digital signals that bring voice, video, and data to and from one or many locations worldwide. Each and every artificial satellite have purpose such as reconnaissance, see weather at earth.
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