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View Modul 5 from TEKNIK at University of Muhammadiyah JARINGAN KOMPUTER PERSIAPAN MATERI - Static Routing. Materi Kuliah Jaringan Komputer - Download as PDF File .pdf), Text File .txt) or view presentation slides online. Outline Materi Kuliah Jaringan Komputer. (MATERI 1) Jaringan Komputer - Download as PDF File .pdf), Text File .txt) or read online. Network Com.

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Konsep Jaringan Komputer. ▫ Kategori Jaringan Komputer. ▫ Topologi Dasar Jaringan Komputer. pdfMachine. A pdf writer that produces quality PDF files with . LAN (Local Area Network) pada era an. Pengantar Jaringan Komputer (3) pdfMachine - is a pdf writer that produces quality PDF files with ease!. View (MATERI 1) Jaringan from INFORMATIC 01 at State University of Surabaya. Data Communication and Computer Network 1. OVERVIEW A.

A system of interconnected computers and computerized peripherals such as printers is called computer network. This interconnection among computers facilitates information sharing among them. Computers may connect to each other by either wired or wireless media. Classification of Computer Networks Computer networks are classified based on various factors. They include:. Inter-Connectivity Components of a network can be connected to each other differently in some fashion. By connectedness we mean either logically, physically, or both ways.

Bit time is divided into two halves. It transits in the middle of the bit and changes phase when a different bit is encountered. It also transits at the middle of the bit but changes phase only when 1 is encountered. It is called Block Coding. This way the original number of bits is increased. Zero voltage represents binary 0 and bit 1 is represented by altering positive and negative voltages. Block coding is represented by slash notation. Bipolar Encoding Bipolar encoding uses three voltage levels.

Block Coding To ensure accuracy of the received data frame. Signals change during bits not between bits. Block coding involves three steps: To transmit this analog data over digital signals.

Data Communication and Computer Network 1. Analog data is a continuous stream of data in the wave form whereas digital data is discrete. Most important factor in sampling is the rate at which analog signal is sampled. It involves three steps: After block coding is done. Division 2. Analog-to-Digital Conversion Microphones create analog voice and camera creates analog videos.

According to Nyquist Theorem. Substitution 3. PCM is one of the most commonly used method to convert analog data into digital form. To convert analog wave into digital data. Sampling The analog signal is sampled every T interval. Encoding In encoding. Every discrete pattern shows the amplitude of the analog signal at that instance.

Transmission Modes The transmission mode decides how data is transmitted between two computers. Quantization is approximation of the instantaneous analog value. The binary data in the form of 1s and 0s can be sent in two different modes: Parallel and Serial.

The quantization is done between the maximum amplitude value and the minimum amplitude value. Data Communication and Computer Network Quantization Sampling yields discrete form of continuous analog signal. Serial transmission can be either asynchronous or synchronous. Serial Transmission In serial transmission.

Both computers distinguish between high order and low order data lines. Both sender and receiver are connected in parallel with the equal number of data lines.

Because the data lines are equal to the number of bits in a group or data frame. Data Communication and Computer Network Parallel Transmission The binary bits are organized into groups of fixed length. Serial transmission requires only one communication channel. Advantage of Parallel transmission is high speed and disadvantage is the cost of wires.

The sender sends all the bits at once on all lines. Data-bits have specific pattern and they help receiver recognize the start and end data bits. The advantage of synchronous transmission is high speed. Data bits are sent in burst mode without maintaining gap between bytes 8bits. Synchronous Serial Transmission Timing in synchronous transmission has importance as there is no mechanism followed to recognize start and end data bits.

It is up to the receiver to recognize and separate bits into bytes. Single burst of data bits may contain a number of bytes. Two continuous data-frames bytes may have a gap between them. Analog signals are modified to reflect digital data.

When low-pass analog signal is converted into bandpass analog signal. The filters are used to filter and pass frequencies of interest.

Low-pass is a filter that passes low frequencies signals. Digital-to-Analog Conversion When data from one computer is sent to another via some analog carrier. When digital data is converted into a bandpass analog signal. A bandpass is a band of frequencies which can pass the filter.

An analog signal is characterized by its amplitude.

Data Communication and Computer Network 9. There are three kinds of digital-to-analog conversions: Amplitude Shift Keying In this conversion technique. There can be two cases according to data formatting. When binary data represents digit 1. Both frequency and phase remain same as in the original carrier signal. Phase Shift Keying In this conversion scheme. When a new binary symbol is encountered. This technique uses two frequencies. Both amplitude and phase of the carrier wave are kept intact.

One of them. Amplitude and frequency of the original carrier signal is kept intact. Analog modulation is required when bandpass is used.

The serial data is converted in to parallel in both sub-streams and then each stream is converted to digital signal using NRZ technique.

Analog to analog conversion can be done in three ways: Amplitude Modulation In this modulation. This conversion is also known as Analog Modulation. This is done in two different phases. The main stream of binary data is divided equally into two sub-streams. Analog-to-Analog Conversion Analog signals are modified to represent analog data. The frequency and phase of carrier signal remain unchanged.

The amplitude of modulating signal analog data is multiplied by the amplitude of carrier frequency. Data Communication and Computer Network Amplitude modulation is implemented by means of a multiplier. Frequency Modulation In this modulation technique. Phase Modulation In the modulation technique.

Data Communication and Computer Network The amplitude and phase of the carrier signal are not altered. Frequency of carrier is signal is changed made dense and sparse to reflect voltage change in the amplitude of modulating signal. The WAN links may not support such high speed. Twisted Pair Cable A twisted pair cable is made of two plastic insulated copper wires twisted together to form a single media.

Magnetic Media One of the most convenient way to transfer data from one computer to another. Even if they do. There are two types of twisted pair cables: The twists between wires are helpful in reducing noise electro-magnetic interference and crosstalk. Data Communication and Computer Network If the bank needs to store its huge backup data. In these cases. Out of these two wires. There are three categories of coax cables namely. UTP cables are connected by RJ45 connectors.

RG stands for Radio Government. The core is enclosed in an insulating sheath. In computer networks. BNC terminator is used to terminate the wire at the far ends. Coaxial Cable Coaxial cable has two wires of copper. This all is covered by plastic cover.

This makes it more indifferent to noise and crosstalk. The core wire lies in the center and it is made of solid conductor. Coaxial cables provide high bandwidth rates of up to mbps. The second wire is wrapped around over the sheath and that too in turn encased by insulator sheath.

UTP has seven categories. Because of its structure. RG Cable TV. The wrapped structure provides it a good shield against noise and cross talk. RG Thin Ethernet. The receiver on the other end de-modulates and interprets the data. They can be spread over several kilometers. When light ray hits at critical angle. The core of fiber optic cable is made of high quality glass or plastic. Broadband PLC provides higher data rates up to s of Mbps and works at higher frequencies 1. PLC can make all powered devices controlled and monitored.

From one end of it light is emitted. Single mode fiber can carry a single ray of light whereas multimode is capable of carrying multiple beams of light. In PLC. There are two types of PLCs: This property has been used in fiber optic. Fiber Optic provides the highest mode of speed. Because power lines are widely deployed. PLC works in half-duplex. Fiber Optics Fiber Optic works on the properties of light. It comes in two modes. They cannot be as much extended as Narrowband PLC. Fiber Optic also comes in unidirectional and bidirectional capabilities.

To connect and access fiber optic special type of connectors are used. Straight Tip ST. These can be Subscriber Channel SC. Radio Transmission Radio frequency is easier to generate and because of its large wavelength it can penetrate through walls and structures alike.

MF bands can travel on the ground up to kilometers. The receptor on the other end receives these signals and converts them back to digital data. Lower frequencies such as VLF. A little part of electromagnetic spectrum can be used for wireless transmission.

When an antenna is attached to electrical circuit of a computer or wireless device. Radio frequencies are sub-divided into six bands. Wireless signals are spread over in the air and are received and interpreted by appropriate antennas. Radio waves can have wavelength from 1mm — High frequency radio waves have more power. Wireless communication involves no physical link established between two or more devices.

Radio waves at lower frequencies can travel through walls whereas higher RF can travel in straight line and bounce back. The power of low frequency waves decreases sharply as they cover long distance. Microwaves can have wavelength ranging from 1mm — 1meter and frequency ranging from MHz to GHz. Because Microwaves travels in straight lines. Microwave Transmission Electromagnetic waves above MHz tend to travel in a straight line and signals over them can be sent by beaming those waves towards one particular station.

Radio waves of high frequencies are prone to be absorbed by rain and other obstacles. They use Ionosphere of earth atmosphere. When they reach Ionosphere. Because laser transmission is unidirectional.

It has wavelength of nm to 1mm and frequency ranges from GHz to THz. As shown in picture above. Infrared wave is used for very short range communication purposes such as television and its remote. Microwave transmission depends highly upon the weather conditions and the frequency it is using.

(MATERI 1) Jaringan Komputer.pdf - Data Communication and...

Infrared travels in a straight line hence it is directional by nature. Data Communication and Computer Network Microwave antennas concentrate the waves making a beam of it. Laser beam is generally 1mm wide hence it is a work of precision to align two far receptors each pointing to lasers source. Because of frequency light uses. Microwaves have higher frequencies and do not penetrate wall like obstacles. Because of high frequency range. Infrared cannot cross wall-like obstacles.

Hence the sender and receiver must be in the line-of-sight. Infrared Transmission Infrared wave lies in between visible light spectrum and microwaves. Light Transmission Highest most electromagnetic spectrum which can be used for data transmission is light or optical signaling.

Laser is safe for data transmission as it is very difficult to tap 1mm wide laser without interrupting the communication channel. Lasers cannot penetrate obstacles such as walls. Each user can transmit data within the provided time slot only. Digital signals are Channels are separated by guard bands.

Materi Kuliah Jaringan Komputer | Routing | Computer Network

When multiple senders try to send over a single medium. FDM is used. On the other end of communication. All channels are divided in such a way that they do not overlap with each other. All mediums are capable of multiplexing. Guard band is a frequency which is not used by either channel. In TDM the shared channel is divided among its user by means of time slot. Time Division Multiplexing TDM is applied primarily on digital signals but can be applied on analog signals as well.

Frequency Division Multiplexing When the carrier is frequency. Each user can use the channel frequency independently and has exclusive access of it. Communication is possible over the air radio frequency. FDM is an analog technology. Multiplexing divides the high capacity medium into low capacity logical medium which is then shared by different streams. FDM divides the spectrum or carrier bandwidth in logical channels and allocates one user to each channel. When channel A transmits its frame at one end.

Both ends. Wavelength Division Multiplexing Light has different wavelength colors. This is an analog multiplexing technique and is done conceptually in the same manner as FDM but uses light as signals. Signals from different channels travel the path in interleaved manner.

Multiplexer and De-multiplexer are timely synchronized. TDM works in synchronized mode. On the other end. In fiber optic mode. Data Communication and Computer Network divided in frames. FDM divides the frequency in smaller channels but CDM allows its users to full bandwidth and transmit signals all the time using a unique code. Each station is assigned with a unique code. Signals travel with these codes independently. The receiver knows in advance the chip code signal it has to receive.

CDM uses orthogonal codes to spread signals. When data comes on a port it is called ingress, and when data leaves a port or goes out it is called egress. A communication system may include number of switches and nodes. At broad level, switching can be divided into two major categories:. The data is forwarded on behalf of forwarding tables. No previous handshaking is required and acknowledgements are optional.

Before switching data to be forwarded to destination, there is a need to pre-establish circuit along the path between both endpoints. Data is then forwarded on that circuit. After the transfer is completed, circuits can be kept for future use or can be turned down immediately. When two nodes communicate with each other over a dedicated communication path, it is called circuit switching. There is a need of pre-specified route from which data travels and no other data is permitted.

In circuit switching to transfer the data, circuit must be established so that the data transfer can take place. Circuits can be permanent or temporary. Applications which use circuit switching may have to go through three phases:. Circuit switching was designed for voice applications. Telephone is the best suitable example of circuit switching. Before a user can make a call, a virtual path between caller and callee is established over the network. This technique was somewhere in middle of circuit switching and packet switching.

A switch working on message switching, first receives the whole message and buffers it until there are resources available to transfer it to the next hop. If the next hop is not having enough resource to accommodate large size message, the message is stored and switch waits. This technique was considered substitute to circuit switching. As in circuit switching the whole path is blocked for two entities only. Message switching is replaced by packet switching. Message switching has the following drawbacks:.

Shortcomings of message switching gave birth to an idea of packet switching. The entire message is broken down into smaller chunks called packets.

The switching information is added in the header of each packet and transmitted independently. It is easier for intermediate networking devices to store small size packets and they do not take much resources either on carrier path or in the internal memory of switches.

Packet switching enables the user to differentiate data streams based on priorities.


The internet uses packet switching technique. This direct connection could be point to point or broadcast. Packets are stored and forwarded according to their priority to provide quality of service. Systems on broadcast network are said to be on same link. Data link layer works between two hosts which are directly connected in some sense.

Data Communication and Computer Network Packet switching enhances line efficiency as packets from multiple applications can be multiplexed over the carrier.

The work of data link layer tends Data link layer hides the details of underlying hardware and represents itself to upper layer as the medium to communicate. This layer is one of the most complicated layers and has complex functionalities and liabilities. It is encoded into hardware at the time of manufacturing. These are: Framing Data-link layer takes packets from Network Layer and encapsulates them into Frames.

Flow Control Stations on same link may have different speed or capacity. Error Control Sometimes signals may have encountered problem in transition and the bits are flipped.

Hardware address is assumed to be unique on the link. It also provides error reporting mechanism to the sender. Synchronization When data frames are sent on the link.

At receiver end. Data link layer has two sub-layers: It deals with protocols. Addressing Data-link layer provides layer-2 hardware addressing mechanism. Multi-Access When host on the shared link tries to transfer the data.

These errors are detected and attempted to recover actual data bits. Data link layer picks up data from hardware which are in the form of electrical signals. At the receiving end. Functionality of Data-link Layer Data link layer does many tasks on behalf of upper layer. Data link layer is responsible for converting data stream to signals bit by bit and to send that over the underlying hardware.

It deals with actual control of media. Data-link layer ensures flow control that enables both machine to exchange data on same speed. The upper layers work on some generalized view of network architecture and are not aware of actual hardware data processing. Most of the applications would not function expectedly if they receive erroneous data.

But to understand how errors is controlled. Multiple bits error Frame is received with more than one bits in corrupted state. Data-link layer uses some error control mechanism to ensure that frames data bit streams are transmitted with certain level of accuracy. Types of Errors There may be three types of errors: Single bit error In a frame.

Applications such as voice and video may not be that affected and with some errors they may still function well.

Burst error Frame contains more than1 consecutive bits corrupted. Before sending the actual bits. If the counter-check at receiver end fails. Actual data bits plus the remainder is called a codeword.

This technique involves binary division of the data bits being sent. Data Communication and Computer Network Error control mechanism may involve two possible ways: But when more than one bits are erroneous. If the count of 1s is odd and odd parity is used. The sender transmits data bits as codewords. If the count of 1s is even and even parity is used.

Parity Check One extra bit is sent along with the original bits to make number of 1s either even in case of even parity. If a single bit flips in transit. The sender while creating a frame counts the number of 1s in it.

The divisor is generated using polynomials. This way number of 1s remains even. The sender performs a division operation on the bits being sent and calculates the remainder. The receiver simply counts the number of 1s in a frame. If the number of 1s is odd. In both cases. If the remainder contains all zeros the data bits are accepted.

But in case of wireless transmission retransmitting may cost too much. Error Correction In the digital world. Forward Error Correction When the receiver detects some error in the data received. Backward Error Correction When the receiver detects an error in the data received.

Backward Error Correction. To locate the bit in error. Forward Error Correction is used. In the latter case. The first one. At the other end. To correct the error in data frame. Data Communication and Computer Network For m data bits. Flow Control When a data frame Layer-2 data is sent from one host to another over a single medium. As we learnt. Sliding Window In this flow control mechanism. Two types of mechanisms can be deployed to control the flow: Stop and Wait This flow control mechanism forces the sender after transmitting a data frame to stop and wait until the acknowledgement of the data-frame sent is received.

If sender is sending too fast the receiver may be overloaded. Requirements for error control mechanism: The sender and receiver. When the receiver receives a damaged frame or a duplicate frame. In such case. If an acknowledgement of a data-frame previously transmitted does not arrive before the timeout. When the receiver receives a correct frame. The sender maintains a clock and sets a timeout period. When the acknowledgement is received. Sender retransmits the frame and starts the timeout counter.

If all frames are positively acknowledged. This enforces the sender to retransmit all the frames which are not acknowledged. The receiving-window enables the receiver to receive multiple frames and acknowledge them. Classification of Computer Networks Computer networks are classified based on various factors.

They include: Inter-Connectivity Components of a network can be connected to each other differently in some fashion. By connectedness we mean either logically, physically, or both ways.

A network can be public, which is accessed by all. Network Architecture Computer networks can be discriminated into various types such as Client-Server, peer-to-peer or hybrid, depending upon its architecture. Other being Client, requests the Server to serve requests. Server takes and processes request on behalf of Clients. They both reside at the same level and called peers. Network Applications Computer systems and peripherals are connected to form a network.

They provide numerous advantages:

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