Jaringan Komunikasi Dan Data UAS

Ah, akhirnya… kalian bisa melihat blog ini dan bilang “oh… post anyar” (dengan nada yg gak begitu nggumun).

Sebenrnya gak perlu belajar buat persiapan UAS besok tapi dibilang gitu juga buat jaga-jaga, tuh ppt yg sebajek kere dibaca juga. (tapi ya tetep cuma sekilas aja). So? Apa yang akan ku tulis untuk kali ini? tebak hayoooo…

Jawabannya adalah “Notes Jarkomdat”. Ta-da!

di setiap ( gak setiap sih) ppt nya pak SJK ada semacam notes yg bisa d bilang penting, tapi juga gak penting. kayak begini ini contohnya (dari chapter 1 mpe 18)

Jarkomdat Notes:



“The physical layer is responsible for transmitting individual bits from one node to the next.”
“The data link layer is responsible for transmitting frames from one node to the next.”
“The network layer is responsible for the delivery of packets from the original source to the
final destination.”
“The transport layer is responsible for delivery of a message from one process to another.”
“The application layer is responsible for providing services to the user.”
“The OSI model is briefly discussed in Appendix C.”


“To be transmitted, data must be transformed to electromagnetic signals.”
“Signals can be analog or digital. Analog signals can have an infinite number of values in a range; digital signals can have only a limited number of values.”
“In data communication, we commonly use periodic analog signals and aperiodic digital signals.”
“Frequency and period are inverses of each other.”
“Frequency is the rate of change with respect to time. Change in a short span of time means high frequency. Change over a long span of time means low frequency.”
“If a signal does not change at all, its frequency is zero. If a signal changes instantaneously, its frequency is infinite.”
“Phase describes the position of the waveform relative to time zero.”
“An analog signal is best represented in the frequency domain.”
“A single-frequency sine wave is not useful in data communications; we need to change one or more of its characteristics to make it useful.”
“When we change one or more characteristics of a single-frequency signal, it becomes a composite signal made of many frequencies.”
“According to Fourier analysis, any composite signal can be represented as a combination of simple sine waves with different frequencies, phases, and amplitudes.”
“The bandwidth is a property of a medium: It is the difference between the highest and the lowest frequencies that the medium can satisfactorily pass.”
“In this book, we use the term bandwidth to refer to the property of a medium or the width of a single spectrum.”
“A digital signal is a composite signal with an infinite bandwidth.”
“The bit rate and the bandwidth are proportional to each other.”
“The analog bandwidth of a medium is expressed in hertz; the digital bandwidth, in bits per second.”
“Digital transmission needs a low-pass channel.”
“Analog transmission can use a band-pass channel.”


“Unipolar encoding uses only one voltage level.”
“Polar encoding uses two voltage levels (positive and negative).”
“In NRZ-L the level of the signal is dependent upon the state of the bit.”
“In NRZ-I the signal is inverted if a 1 is encountered.”
“A good encoded digital signal must contain a provision for synchronization.”
“In Manchester encoding, the transition at the middle of the bit is used for both synchronization and bit representation.”
“In differential Manchester encoding, the transition at the middle of the bit is used only for synchronization. The bit representation is defined by the inversion or non-inversion at the beginning of the bit.”
“In bipolar encoding, we use three levels: positive, zero, and negative.”
“Pulse amplitude modulation has some applications, but it is not used by itself in data communication. However, it is the first step in another very popular conversion method called pulse code modulation.”
“According to the Nyquist theorem, the sampling rate must be at least 2 times the highest frequency.”
“Note that we can always change a band-pass signal to a low-pass signal before sampling. In this case, the sampling rate is twice the bandwidth.”
“In asynchronous transmission, we send 1 start bit (0) at the beginning and 1 or more stop bits (1s) at the end of each byte. There may be a gap between each byte.”
“Asynchronous here means “asynchronous at the byte level,” but the bits are still synchronized; their durations are the same.”
“In synchronous transmission, we send bits one after another without start/stop bits or gaps. It is the responsibility of the receiver to group the bits.”


“Bit rate is the number of bits per second. Baud rate is the number of signal units per second. Baud rate is less than or equal to the bit rate.”
“Quadrature amplitude modulation is a combination of ASK and PSK so that a maximum contrast between each signal unit (bit, dibit, tribit, and so on) is achieved.”
“A telephone line has a bandwidth of almost 2400 Hz for data transmission.”
“Modem stands for modulator/demodulator.”
“The total bandwidth required for AM can be determined from the bandwidth of the audio signal: BWt = 2 x BWm.”
“The total bandwidth required for FM can be determined from the bandwidth of the audio signal: BWt = 10 x BWm.”
“The bandwidth of a stereo audio signal is usually 15 KHz. Therefore, an FM station needs at least a bandwidth of 150 KHz. The FCC requires the minimum bandwidth to be at least 200 KHz (0.2 MHz).”


“FDM is an analog multiplexing technique that combines signals.”
“WDM is an analog multiplexing technique to combine optical signals.”
“TDM is a digital multiplexing technique to combine data.”
“In a TDM, the data rate of the link is n times faster, and the unit duration is n times shorter.”


“Radio waves are used for multicast communications, such as radio and television, and paging systems.”
“Microwaves are used for unicast communication such as cellular telephones, satellite networks, and wireless LANs.”
“Infrared signals can be used for short-range communication in a closed area using line-of-sight propagation.”


“Intra-LATA services are provided by local exchange carriers. Since 1996, there are two types of LECs: incumbent local exchange carriers and competitive local exchange carriers.”
“Voice communication used analog signals in the past, but is now moving to digital signals. On the other hand, dialing started with digital signals (rotary) and is now moving to analog signals (touch-tone).”


“ADSL is an asymmetric communication technology designed for residential users; it is not suitable for businesses.”
“The existing local loops can handle bandwidths up to 1.1 MHz.”
“ADSL is an adaptive technology. The system uses a data rate based on the condition of the local loop line.”
“Communication in the traditional cable TV network is unidirectional.”
“Communication in an HFC cable TV network can be bidirectional.”
“Downstream data are modulated using the 64-QAM modulation technique.”
“The theoretical downstream data rate is 30 Mbps.”
“Upstream data are modulated using the QPSK modulation technique.”
“The theoretical upstream data rate is 12 Mbps.”
“SONET is a synchronous TDM system controlled by a master clock.”


“Data can be corrupted during transmission. For reliable communication, errors must be detected and corrected.”
“In a single-bit error, only one bit in the data unit has changed.”
“A burst error means that 2 or more bits in the data unit have changed.”
“Error detection uses the concept of redundancy, which means adding extra bits for detecting errors at the destination.”
“In parity check, a parity bit is added to every data unit so that the total number of 1s is even (or odd for odd-parity).”
“Simple parity check can detect all single-bit errors. It can detect burst errors only if the total number of errors in each data unit is odd.”
“In two-dimensional parity check, a block of bits is divided into rows and a redundant row of bits is added to the whole block.”
“The sender follows these steps:
•The unit is divided into k sections, each of n bits.
•All sections are added using one’s complement to get the sum.
•The sum is complemented and becomes the checksum.
•The checksum is sent with the data.”
“The receiver follows these steps:
•The unit is divided into k sections, each of n bits.
•All sections are added using one’s complement to get the sum.
•The sum is complemented.
•If the result is zero, the data are accepted: otherwise, rejected.”


“Flow control refers to a set of procedures used to restrict the amount of data that the sender can send before waiting for acknowledgment.”
“Error control in the data link layer is based on automatic repeat request, which is the retransmission of data.”
“In Stop-and-Wait ARQ, numbering frames prevents the retaining of duplicate frames.”
“Numbered acknowledgments are needed if an acknowledgment is delayed and the next frame is lost.”
“In Go-Back-N ARQ, the size of the sender window must be less than 2^m; the size of the receiver window is always 1.”
“In Selective Repeat ARQ, the size of the sender and receiver window must be at most one-half of 2^m.”
“Bit stuffing is the process of adding one extra 0 whenever there are five consecutive 1s in the data so that the receiver does not mistake the data for a flag.”



“In FDMA, the bandwidth is divided into channels.”
“In TDMA, the bandwidth is just one channel that is timeshared.”
“In CDMA, one channel carries all transmissions simultaneously.”




“A repeater connects segments of a LAN.”
“A repeater forwards every frame; it has no filtering capability.”
“A repeater is a regenerator, not an amplifier.”
“A bridge has a table used in filtering decisions.”
“A bridge does not change the physical (MAC) addresses in a frame.”
“In a bus backbone, the topology of the backbone is a bus.”
“In a star backbone, the topology of the backbone is a star; the backbone is just one switch.”
“A point-to-point link acts as a LAN in a remote backbone connected by remote bridges.”
“VLANs create broadcast domains.”


“AMPS is an analog cellular phone system using FDMA.”
“D-AMPS, or IS-136, is a digital cellular phone system using TDMA and FDMA.”
“GSM is a digital cellular phone system using TDMA and FDMA.”
“IS-95 is a digital cellular phone system using CDMA/DSSS and FDMA.”
“The main goal of third-generation cellular telephony is to provide universal personal communication.”
“The Iridium system has 66 satellites in six LEO orbits, each at an altitude of 750 km.”
“Iridium is designed to provide direct worldwide voice and data communication using handheld terminals, a service similar to cellular telephony but on a global scale.”
“Teledesic has 288 satellites in 12 LEO orbits, each at an altitude of 1350 km.”


“VCIs in Frame Relay are called DLCIs.”
“Frame Relay operates only at the physical and data link layers.”
“Frame Relay does not provide flow or error control; they must be provided by the upper-layer protocols.”
“A cell network uses the cell as the basic unit of data exchange. A cell is defined as a small, fixed-sized
block of information.”
“Note that a virtual connection is defined by a pair of numbers: the VPI and the VCI.”

Sekian ajalah, mu ngeprint PPT nya dulu. lol

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