Networking Basic

Assignment A

1 Describe the benefits of computer networking. How it is impacting the human lives in positive aspects? Classify the networks on the basis of their size with the importance of each classification. 

3. Give the importance of Data Transmission. How Simplex, Half duplex & full duplex are different in data transmission technology. Briefly describe the Analog and Digital Data Transmission with their pros and cons. 
Ans- Data transmission (also data communication or digital communications) is the transfer of data (a digital bitstream or a digitized analog signal) over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibers, wireless communication channels, storage media and computer buses. The data are represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave, or infrared signal.

Analog or analogue transmission is a transmission method of conveying voice, data, image, signal or video information using a continuous signal which varies in amplitude, phase, or some other property in proportion to that of a variable. The messages are either represented by a sequence of pulses by means of a line code (baseband transmission), or by a limited set of continuously varying wave forms (passband transmission), using a digital modulation method. The passband modulation and corresponding demodulation (also known as detection) is carried out by modem equipment. According to the most common definition of digital signal, both baseband and passband signals representing bit-streams are considered as digital transmission, while an alternative definition only considers the baseband signal as digital, and passband transmission of digital data as a form of digital-to-analog conversion.

Data transmitted may be digital messages originating from a data source, for example a computer or a keyboard. It may also be an analog signal such as a phone call or a video signal, digitized into a bit-stream, for example, using pulse-code modulation (PCM) or more advanced source coding (analog-to-digital conversion and data compression) schemes. This source coding and decoding is carried out by codec equipment.

1    Distinction between related subjects
2    Protocol layers and sub-topics
3    Applications and history
4    Serial and parallel transmission
5    Types of communication channels (Network topologies)
6    Asynchronous and synchronous data transmission
7    See also
8    Notes
Distinction between related subjects
Courses and textbooks in the field of data transmission as well as digital transmission and digital communications have similar content.

Digital transmission or data transmission traditionally belongs to telecommunications and electrical engineering. Basic principles of data transmission may also be covered within the computer science/computer engineering topic of data communications, which also includes computer networking or computer communication applications and networking protocols, for example routing, switching and inter-process communication. Although the Transmission control protocol (TCP) involves the term "transmission", TCP and other transport layer protocols are typically not discussed in a textbook or course about data transmission, but in computer networking.

The term tele transmission involves the analog as well as digital communication. In most textbooks, the term analog transmission only refers to the transmission of an analog message signal (without digitization) by means of an analog signal, either as a non-modulated baseband signal, or as a passband signal using an analog modulation method such as AM or FM. It may also include analog-over-analog pulse modulatated baseband signals such as pulse-width modulation. In a few books within the computer networking tradition, "analog transmission" also refers to passband transmission of bit-streams using digital modulation methods such as FSK, PSK and ASK. Note that these methods are covered in textbooks named digital transmission or data transmission, for example.

The theoretical aspects of data transmission are covered by information theory and coding theory.

Protocol layers and sub-topics
OSI model by layer
7.  Application layer
6.  Presentation layer
5.  Session layer
4.  Transport layer
3.  Network layer
2.  Data link layer
1.  Physical layer

Courses and textbooks in the field of data transmission typically deal with the following OSI model protocol layers and topics:

Layer 1, the physical layer:
Channel coding including
Digital modulation schemes
Line coding schemes
Forward error correction (FEC) codes
Bit synchronization
Multiplexing
Equalization
Channel models
Layer 2, the data link layer:
Channel access schemes, media access control (MAC)
Packet mode communication and Frame synchronization
Error detection and automatic repeat request (ARQ)
Flow control
Layer 6, the presentation layer:
Source coding (digitization and data compression), and information theory.
Cryptography (may occur at any layer)

Applications and history
Data (mainly but not exclusively informational) has been sent via non-electronic (e.g. optical, acoustic, mechanical) means since the advent of communication. Analog signal data has been sent electronically since the advent of the telephone. However, the first data electromagnetic transmission applications in modern time were telegraphy (1809) and teletypewriters (1906), which are both digital signals. The fundamental theoretical work in data transmission and information theory by Harry Nyquist, Ralph Hartley, Claude Shannon and others during the early 20th century, was done with these applications in mind.

Data transmission is utilized in computers in computer buses and for communication with peripheral equipment via parallel ports and serial ports such as RS-232 (1969), Firewire (1995) and USB (1996). The principles of data transmission are also utilized in storage media for Error detection and correction since 1951.

Data transmission is utilized in computer networking equipment such as modems (1940), local area networks (LAN) adapters (1964), repeaters, repeater hubs, microwave links, wireless network access points (1997), etc.

In telephone networks, digital communication is utilized for transferring many phone calls over the same copper cable or fiber cable by means of Pulse code modulation (PCM), i.e. sampling and digitization, in combination with Time division multiplexing (TDM) (1962). Telephone exchanges have become digital and software controlled, facilitating many value added services. For example, the first AXE telephone exchange was presented in 1976. Since the late 1980s, digital communication to the end user has been possible using Integrated Services Digital Network (ISDN) services. Since the end of the 1990s, broadband access techniques such as ADSL, Cable modems, fiber-to-the-building (FTTB) and fiber-to-the-home (FTTH) have become widespread to small offices and homes. The current tendency is to replace traditional telecommunication services by packet mode communication such as IP telephony and IPTV.

Transmitting analog signals digitally allows for greater signal processing capability. The ability to process a communications signal means that errors caused by random processes can be detected and corrected. Digital signals can also be sampled instead of continuously monitored. The multiplexing of multiple digital signals is much simpler to the multiplexing of analog signals.

Because of all these advantages, and because recent advances in wideband communication channels and solid-state electronics have allowed scientists to fully realize these advantages, digital communications has grown quickly. Digital communications is quickly edging out analog communication because of the vast demand to transmit computer data and the ability of digital communications to do so.

The digital revolution has also resulted in many digital telecommunication applications where the principles of data transmission are applied. Examples are second-generation (1991) and later cellular telephony, video conferencing, digital TV (1998), digital radio (1999), telemetry, etc.

Data transmission, digital transmission or digital communications is the physical transfer of data (a digital bit stream or a digitized analog signal) over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibers, wireless communication channels, storage media and computer buses. The data are represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave, or infrared signal.

While analog transmission is the transfer of a continuously varying analog signal over an analog channel, digital communications is the transfer of discrete messages over a digital or an analog channel. The messages are either represented by a sequence of pulses by means of a line code (baseband transmission), or by a limited set of continuously varying wave forms (passband transmission), using a digital modulation method. The passband modulation and corresponding demodulation (also known as detection) is carried out by modem equipment. According to the most common definition of digital signal, both baseband and passband signals representing bit-streams are considered as digital transmission, while an alternative definition only considers the baseband signal as digital, and passband transmission of digital data as a form of digital-to-analog conversion.

Data transmitted may be digital messages originating from a data source, for example a computer or a keyboard. It may also be an analog signal such as a phone call or a video signal, digitized into a bit-stream for example using pulse-code modulation (PCM) or more advanced source coding (analog-to-digital conversion and data compression) schemes. This source coding and decoding is carried out by codec equipment.

Serial and parallel transmission
In telecommunications, serial transmission is the sequential transmission of signal elements of a group representing a character or other entity of data. Digital serial transmissions are bits sent over a single wire, frequency or optical path sequentially. Because it requires less signal processing and less chances for error than parallel transmission, the transfer rate of each individual path may be faster. This can be used over longer distances as a check digit or parity bit can be sent along it easily.

In telecommunications, parallel transmission is the simultaneous transmission of the signal elements of a character or other entity of data. In digital communications, parallel transmission is the simultaneous transmission of related signal elements over two or more separate paths. Multiple electrical wires are used which can transmit multiple bits simultaneously, which allows for higher data transfer rates than can be achieved with serial transmission. This method is used internally within the computer, for example the internal buses, and sometimes externally for such things as printers, The major issue with this is "skewing" because the wires in parallel data transmission have slightly different properties (not intentionally) so some bits may arrive before others, which may corrupt the message. A parity bit can help to reduce this. However, electrical wire parallel data transmission is therefore less reliable for long distances because corrupt transmissions are far more likely.

  
7 How File Transfer Protocols is different from Trivial File Transfer Protocol? Explain. 
 Describe the working of SNMP with its pros and cons. How SNMP is different from POP? 
 UDP 

Assignment B
  
Case study 

Networking not only enables sharing information and resources among the users but also distributed processing. There are five types of network. Point-point, LAN, MAN, WAN and VAN. Point-point allows sharing of files at a very low speed. LANs are networks distributed over a small geographical area. They can be configured peer-peer or much powerful client/server model. MANs cover entire metropolitan area and may have private lines. WANs cover relatively large geographical area. Here machines are called hosts connected by subnets. The Internet is the largest WAN. VANs are communications networks supplied and managed by third-party companies that facilitate electronic data interchange, Web services and transaction delivery by providing extra networking services. The network topology defines how the devices (computers, printers etc) are connected and how the data flows from one device to another. They topology all devices are connected to the transmission medium as backbone. Ring topology was in the beginning of LAN area. In a star topology each station is connected to a central node. The central node can be either a hub or a switch. A mesh physical topology is when every device on the network is connected to every device on the network; most commonly used in WAN configurations. A hybrid topology is a combination of any two or more network topologies in such a way that the resulting network does not have one of the standard forms.  

Q.No 1: How different toplogies are associated with netowring in WAN structure? Explain. 

Q.No 2: MTNL wants to establish its telephone network in whole NOIDA area. Describe that which type of networking will be well suited for it? Also describe the various steps for establishment of it. 

Q.No 3: Hybrid topology is much better than single topology. Justify this statement with facts and examples. 

Assignment C

Question 1

OSI stands for 

 (A): open system interconnection 

 (B): operating system interface 

 (C): optical service implementation 

 (D): none of the mentioned 
 

The OSI model has ___ layers. 

 (A): 4 

 (B): 5 

 (C): 6 

 (D): 7 
 

TCP/IP model does not have ______ layer but OSI model have this layer. 

 (A): session layer 

 (B): presentation layer 

 (C): application layer 

 (D): both (a) and (b) 
 

Which layer links the network support layers and user support layers 

 (A): session layer 

 (B): data link layer 

 (C): transport layer 

 (D): network layer 
 

Which address is used in an internet employing the TCP/IP protocols? 

 (A): physical address and logical address 

 (B): port address 

 (C): specific address 

 (D): all of the mentioned 
 

TCP/IP model was developed _____ the OSI model. 

 (A): prior to 

 (B): after 

 (C): simultaneous to 

 (D): none of the mentioned 
 

Which layer is responsible for process to process delivery? 

 (A): network layer 

 (B): transport layer 

 (C): session layer 

 (D): data link layer 
 

Which address identifies a process on a host? 

 (A): physical address 

 (B): logical address 

 (C): port address 

 (D): specific address 
 

Which layer provides the services to user? 

 (A): application layer 

 (B): session layer 

 (C): presentation layer 

 (D): none of the mentioned 
 

Transmission data rate is decided by 

 (A): network layer 

 (B): physical layer 

 (C): data link layer 

 (D): transport layer 
 

The IETF standards documents are called 

 (A): RFC 

 (B): RCF 

 (C): ID 

 (D): None of the mentioned 
 

In the layer hierarchy as the data packet moves from the upper to the lower layers, headers are 

 (A): Added 

 (B): Removed 

 (C): Rearranged 

 (D): Modified 
 

The structure or format of data is called 

 (A): Syntax 

 (B): Semantics 

 (C): Struct 

 (D): None of the mentioned 
 

Communication between a computer and a keyboard involves ______________ transmission 

 (A): Automatic 

 (B): Half-duplex 

 (C): Full-duplex 

 (D): Simplex 
 

The first Network 

 (A): CNNET 

 (B): NSFNET 

 (C): ASAPNET 

 (D): ARPANET 
 

The _______ is the physical path over which a message travels 

 (A): Path 

 (B): Medium 

 (C): Protocol 

 (D): Route 
 

Which organization has authority over interstate and international commerce in the communications field? 

 (A): ITU-T 

 (B): IEEE 

 (C): FCC 

 (D): ISOC 
 

Which of this is not a network edge device? 

 (A): PC 

 (B): Smartphones 

 (C): Servers 

 (D): Switch 
 

A set of rules that governs data communication 

 (A): Protocols 

 (B): Standards 

 (C): RFCs 

 (D): None of the mentioned 
 

Three or more devices share a link in ________ connection 

 (A): Unipoint 

 (B): Multipoint 

 (C): Point to point 

 (D): None of the mentioned 
 

.................... refers to information that is continuous. 

 (A): Analog data 

 (B): Digital data 

 (C): Analog signal 

 (D): Digital signal 
 

.................. refers to information that has discrete states. 

 (A): Analog data 

 (B): Digital data 

 (C): Analog signal 

 (D): Digital signal 

............... has infinitely many levels of intensity over a period of time. 

 (A): Analog data 

 (B): Digital data 

 (C): Analog signal 

 (D): Digital signal 
 

.............. can have only limited number of defined values which is often simple as 0 or 1. 

 (A): Analog data 

 (B): Digital data 

 (C): Analog signal 

 (D): Digital signal 
 

A .................... signal completes a pattern with in a measurable time frame called a period and repeats that pattern over subsequent identical periods. 

 (A): periodic 

 (B): framed 

 (C): non periodic 

 (D): discrete 
 
SAVE & NEXT    

The ................. of a signal is the absolute value of its highest intensity, proportional to the energy it carries. 

 (A): phase 

 (B): peak amplitude 

 (C): frequency period 

 (D): period 
 

.................... refers to the amount of time in seconds, a signal needs to complete one cycle. 

 (A): phase 

 (B): peak amplitude 

 (C): frequency 

 (D): period 
 

............... is the position of the waveform relative to time 0. 

 (A): phase 

 (B): peak amplitude 

 (C): frequency 

 (D): period 
 

........................ is the rate of change with respect to time. 

 (A): phase 

 (B): peak amplitude 

 (C): frequency 

 (D): period 
 

................. is a characteristic of a signal traveling through a transmission medium which binds the period or the frequency of a simple sine wave to the propagation speed of the medium. 

 (A): Period 

 (B): Frequency 

 (C): Web-length 

 (D): Phase 
 

. ................ is actually a combination of simple sine waves with different frequencies, amplitudes and phases. 

 (A): Composite signal 

 (B): Combined signal 

 (C): Hybrid signal 

 (D): All of the above 
 

A ............. can be transmitted only a limited distance before attenuation, noise and other impairments distorts the integrity of the data. 

 (A): Analog signal 

 (B): Digital signal 

 (C): Hybrid signal 

 (D): All of the above 
 
SAVE & NEXT    

To achieve longer distances, the analog transmission system includes ................... that boost the energy of the signal. 

 (A): repeaters 

 (B): amplifiers 

 (C): routers 

 (D): boosters 
 
SAVE & NEXT    

A .................... receives the digital signal, recovers the pattern of 1s and 0s and re-transmits a new signal. 

 (A): repeater 

 (B): amplifier 

 (C): router 

 (D): booster 
 

State whether the following statements are True or False for digital signal....i) Analog data are encoded using a codec to produce digital bit stream ii) Digital data are encoded to produce a digital signal with desired properties. 

 (A): i-True, ii-False 

 (B): i-True, ii-True 

 (C): i-False, ii-True 

 (D): i-False, ii-False 
 
SAVE & NEXT    

In digital transmission, analog signal propagated through .................... 

 (A): repeaters 

 (B): amplifiers 

 (C): routers 

 (D): boosters 
 

We can compare the performance of analog transmission with that of digital transmission system based on the following factors. i) effect of noise  ii) distance to be covered  iii) services provided 

 (A): i and ii only 

 (B): ii and iii only 

 (C): i and iii only 

 (D): All i, ii and iii 
 

................. receive the signal and noise at their input separate out the signal from noise and regenerate the signal which is free from noise. 

 (A): repeaters 

 (B): amplifiers 

 (C): routers 

 (D): separators 
 

Which of the following are the advantages of digital transmission. i) Digital transmission has better noise immunity ii) It is possible to  detect and correct the errors iii) Digital transmission require a larger channel bandwidth as compared to analog 

 (A): i and ii only 

 (B): ii and iii only 

 (C): i and iii only 

 (D): All i, ii and iii 
 

Firewalls are often configured to block 

 (A): UDP traffic 

 (B): TCP traffic 

 (C): Both of the mentioned 

 (D): None of the mentioned