Aiou Solved Assignments code 5646 Autumn 2019 asignments 1 and 2 Resource Sharing and Networking-II code 5646 spring 2019. solved aiou past papers.
AIOU Solved Assignments 1 & 2 Code 5646 Autumn 2019
Course: Resource Sharing and Networking-II (5646)
Semester: Spring, 2019
ASSIGNMENT No. 1
Q.1 Define data transmission. Discuss different types of data transmission with examples.
Data transmission refers to the process of transferring data between two or more digital devices. Data is transmitted from one device to another in analog or digital format. Basically, data transmission enables devices or components within devices to speak to each other.
Data is transferred in the form of bits between two or more digital devices. There are two methods used to transmit data between digital devices: serial transmission and parallel transmission. Serial data transmission sends data bits one after another over a single channel. Parallel data transmission sends multiple data bits at the same time over multiple channels.
When we enter data into the computer via keyboard, each keyed element is encoded by the electronics within the keyboard into an equivalent binary coded pattern, using one of the standard coding schemes that are used for the interchange of information. To represent all characters of the keyboard, a unique pattern of 7 or 8 bits in size is used. The use of 7 bits means that 128 different elements can be represented, while 8 bits can represent 256 elements. A similar procedure is followed at the receiver that decodes every received binary pattern into the corresponding character.
Data transmission refers to the movement of data in form of bits between two or more digital devices. This transfer of data takes place via some form of transmission media (for example, coaxial cable, fiber optics etc.)
Types of Data Transmission
- Parallel transmission
Within a computing or communication device, the distances between different subunits are too short. Thus, it is normal practice to transfer data between subunits using a separate wire to carry each bit of data. There are multiple wires connecting each sub-unit and data is exchanged using a parallel transfer mode. This mode of operation results in minimal delays in transferring each word.
• In parallel transmission, all the bits of data are transmitted simultaneously on separate communication lines.
• In order to transmit n bits, n wires or lines are used. Thus each bit has its own line.
• All n bits of one group are transmitted with each clock pulse from one device to another i.e. multiple bits are sent with each clock pulse.
• Parallel transmission is used for short distance communication.
• As shown in the fig, eight separate wires are used to transmit 8 bit data from sender to receiver.
- Serial Transmission
When transferring data between two physically separate devices, especially if the separation is more than a few kilometers, for reasons of cost, it is more economical to use a single pair of lines. Data is transmitted as a single bit at a time using a fixed time interval for each bit. This mode of transmission is known as bit-serial transmission.
• In serial transmission, the various bits of data are transmitted serially one after the other.
• It requires only one communication line rather than n lines to transmit data from sender to receiver.
• Thus all the bits of data are transmitted on single line in serial fashion.
• In serial transmission, only single bit is sent with each clock pulse.
• As shown in fig., suppose an 8-bit data 11001010 is to be sent from source to destination. Then least significant bit (LSB) i,e. 0 will be transmitted first followed by other bits. The most significant bit (MSB) i.e. 1 will be transmitted in the end via single communication line.
• The internal circuitry of computer transmits data in parallel fashion. So in order to change this parallel data into serial data, conversion devices are used.
• These conversion devices convert the parallel data into serial data at the sender side so that it can be transmitted over single line.
• On receiver side, serial data received is again converted to parallel form so that the interval circuitry of computer can accept it
• Serial transmission is used for long distance communication.
Types of Serial Transmission
There are two types of serial transmission-synchronous and asynchronous both these transmissions use ‘Bit synchronization’
Bit Synchronization is a function that is required to determine when the beginning and end of the data transmission occurs.
Bit synchronization helps the receiving computer to know when data begin and end during a transmission. Therefore bit synchronization provides timing control.
• Asynchronous transmission sends only one character at a time where a character is either a letter of the alphabet or number or control character i.e. it sends one byte of data at a time.
• Bit synchronization between two devices is made possible using start bit and stop bit.
• Start bit indicates the beginning of data i.e. alerts the receiver to the arrival of new group of bits. A start bit usually 0 is added to the beginning of each byte.
• Stop bit indicates the end of data i.e. to let the receiver know that byte is finished, one or more additional bits are appended to the end of the byte. These bits, usually 1s are called stop bits.
• Addition of start and stop increase the number of data bits. Hence more bandwidth is consumed in asynchronous transmission.
• There is idle time between the transmissions of different data bytes. This idle time is also known as Gap
• The gap or idle time can be of varying intervals. This mechanism is called Asynchronous, because at byte level sender and receiver need not to be synchronized. But within each byte, receiver must be synchronized with the incoming bit stream.
• Synchronous transmission does not use start and stop bits.
• In this method bit stream is combined into longer frames that may contain multiple bytes.
• There is no gap between the various bytes in the data stream.
• In the absence of start & stop bits, bit synchronization is established between sender & receiver by ‘timing’ the transmission of each bit.
• Since the various bytes are placed on the link without any gap, it is the responsibility of receiver to separate the bit stream into bytes so as to reconstruct the original information.
• In order to receive the data error free, the receiver and sender operates at the same clock frequency. Aiou Solved Assignments code 5646 ,
AIOU Solved Assignments 1 Code 5646 Autumn 2019
Q.2 Describe topologies of LAN with examples.
Network topologies can take a bit of time to understand when you’re all new to this kind of cool stuff, but it’s very important to fully understand them as they are key elements to understanding and troubleshooting networks and will help you decide what actions to take when you’re faced with network problems.
PHYSICAL AND LOGICAL TOPOLOGIES
There are two types of topologies: Physical and Logical. The physical topology of a network refers to the layout of cables, computers and other peripherals. Try to imagine yourself in a room with a small network, you can see network cables coming out of every computer that is part of the network, then those cables plug into a hub or switch. What you’re looking at is the physical topology of that network!
Logical topology is the method used to pass the information between the computers. In other words, looking at that same room, if you were to try to see how the network works with all the computers talking (think of the computers generating traffic and packets of data going everywhere on the network) you would be looking at the logical part of the network. The way the computers will be talking to each other and the direction of the traffic is controlled by the various protocols (like Ethernet) or, if you like, rules.
If we used token ring, then the physical topology would have to change to meet the requirements of the way the token ring protocol works (logically).
If it’s all still confusing, consider this: The physical topology describes the layout of the network, just like a map shows the layout of various roads, and the logical topology describes how the data is sent accross the network or how the cars are able to travel (the direction and speed) at every road on the map.
The most common types of physical topologies, which we are going to analyse, are: Bus, Hub/Star and Ring
THE PHYSICAL BUS TOPOLOGY
Bus topology is fairly old news and you probably won’t be seeing much of these around in any modern office or home. With the Bus topology, all workstations are connect directly to the main backbone that carries the data. Traffic generated by any computer will travel across the backbone and be received by all workstations. This works well in a small network of 2-5 computers, but as the number of computers increases so will the network traffic and this can greatly decrease the performance and available bandwidth of your network.
THE PHYSICAL HUB OR STAR TOPOLOGY
The Star or Hub topology is one of the most common network topologies found in most offices and home networks. It has become very popular in contrast to the bus type (which we just spoke about), because of the cost and the ease of troubleshooting.
The advantage of the star topology is that if one computer on the star topology fails, then only the failed computer is unable to send or receive data. The remainder of the network functions normally. The disadvantage of using this topology is that because each computer is connected to a central hub or switch, if this device fails, the entire network fails! A classic example of this type of topology is the UTP (10 base T), which normaly has a blue colour. Personally I find it boring, so I decided to go out and get myself green, red and yellow colours
THE PHYSICAL RING TOPOLOGY
In the ring topology, computers are connected on a single circle of cable. Unlike the bus topology, there are no terminated ends. The signals travel around the loop in one direction and pass through each computer, which acts as a repeater to boost the signal and send it to the next computer. On a larger scale, multiple LANs can be connected to each other in a ring topology by using Thicknet coaxial or fiber-optic cable.
THE PHYSICAL MESH TOPOLOGY
In a mesh topology, each computer is connected to every other computer by a separate cable. This configuration provides redundant paths through the new work, so if one computer blows up, you don’t lose the network 🙂 On a large scale, you can connect multiple LANs using mesh topology with leased telephone lines, Thicknet coaxial cable or fiber optic cable. Again, the big advantage of this topology is its backup capabilities by providing multiple paths through the network.
THE PHYSICAL HYBRID TOPOLOGY
With the hybrid topology, two or more topologies are combined to form a complete network. For example, a hybrid topology could be the combination of a star and bus topology. These are also the most common in use.
In a star-bus topology, several star topology networks are linked to a bus connection. In this topology, if a computer fails, it will not affect the rest of the network. However, if the central component, or hub, that attaches all computers in a star, fails, then you have big problems since no computer will be able to communicate.
In the Star-Ring topology, the computers are connected to a central component as in a star network. These components, however, are wired to form a ring network. Like the star-bus topology, if a single computer fails, it will not affect the rest of the network. By using token passing, each computer in a star-ring topology has an equal chance of communicating. This allows for greater network traffic between segments than in a star-bus topology.
AIOU Solved Assignments 2 Code 5646 Autumn 2019
Q.3 Explore practices and opportunities on cooperative collection development and technical processing in libraries.
Cooperative collection development is the method in which two or more libraries agree to have certain areas of primary collecting responsibility and exchange such materials with one another free of cost. This involves physical access through resource sharing, bibliographic access and coordinated collection development and management. The basic objective is to reduce wasteful duplication of intellectual effort and the expenses incurred in providing duplicate coverage of the same material. Participating libraries can increase their resources to provide better services and facilities without increase in expenditure (Khanna, 2001).
Resource sharing involves activities engaged in jointly by a group of libraries for the purposes of improving services and/or cutting costs. Proliferation of literature in every field of knowledge, countless documents in various subjects, languages and formats, emergence of new specializations and subject areas, diversity of user groups, increase in reader community and information seekers etc. have necessitated sharing of resources among libraries.
Resource sharing may be informal or formal and may operate locally, nationally or internationally. Inter library loan (ILL) is the most prevalent form of library co-operation and effective and speedy delivery is central to the success of resource sharing. Bibliographic access to the holdings of other libraries is necessary for cooperation and online shared catalogues and web-based access to online catalogues are a big step in this direction.
Areas of resource sharing in Library:
- Cooperative acquisition or funding: Centralised agency should handle orders of all libraries for books and periodicals to be acquired against available funds. Also acquires expensive and less used items which are placed either in a central site or in the library with the highest anticipated local use.
- Cooperative cataloguing: Libraries jointly establish a centralised system of classification and cataloguing either regionally or nationally to avoid duplication, wastage of time, money and labor. It brings uniformity and improve quality in the technical processing of participating libraries.
- Synergistic approach: different libraries take responsibility to collect in different areas according to some collaborative plan. It divides the universe of information into core and peripheral materials and further divides the periphery among the consortium members.
- Coordinated weeding and retention reduce costs by sharing responsibilities and take responsibility for retaining materials in certain areas. The practice of last-copy retention is followed where it is ensured that at least a single copy is preserved in the consortium or geographic area before weeding.
- Coordinated preservation initiatives include shared mass digitization projects like Google Books Library Project which in addition to increasing access to resources also preserves the content for posterity.
- Union catalogue is an inventory common to several libraries containing all or some of their publications. It gives unified information about collections of different libraries, and makes ILL possible.
- Cooperative storage: Libraries can join to have a cooperative storage for little used and weeded out reading materials by sharing among themselves the cost involved (Prasher, 2002).
Benefits of Cooperation
Coordinated collection development arrangements provide support for economic and cost-effective collection development, reduction of responsibility to acquire and preserve in certain areas, greater selectivity in certain areas, planned cost reduction, coordination in storing and cancelling materials, coordination of retention policies for little-used materials, last copy, serial back files etc., reduce unwanted redundancy and unintended duplication (Mosher & Pankake, 1983).
Collaboration in the acquisition of e-resources has great advantages for libraries as this provides expanded access to a greater domain of materials than the libraries can independently support. The consortium is able to extract more favorable licensing terms which in turn reduces the cost and time on libraries to involve in license negotiation. Cost allocation for products also varies with consortium; the allocation may be equitable to member libraries of equal size or may have the differential pricing where the cost is proportionally divided according to the size of the user population based on the enrolled users served by the library. Having centralized staff to administer and negotiate contracts also relieves the libraries from engaging in these activities there by saving additional costs.
Problems of coordinated collection development:
The problems include policy failures like lack of coordinated collection development policies and statements, lack of understanding and support from faculty and other groups, failure to reflect institutional program needs and incorporate changes in the programs, negative budget implications like cutting short of budgets, lack of institutional incentives etc., balancing commitment to the needs of local clientele while fulfilling other cooperative needs, ensuring bibliographic access to the total range of information resources available to cooperating libraries, negotiating licensing and ownership agreements when shared use is limited by vendors. It is also a challenge to analyse the costs and benefits of various approaches for providing materials (Association for Library Collections & Technical Services, 1994).
Effective coordinated collection development activities require a desirable balance between the local needs and priorities and the priorities of the larger cooperating group. Successful cooperative initiatives require efficient governance and a high degree of trust between institutions and librarians, competent consortium administrator, clarity and understanding among the partners and a reliable communication system to share policy decisions.
Liaison Activities and Community Outreach
Liaison activities are essential for collection development and management which involves faculty-librarian collaboration in academic libraries. Awareness about faculty’s special interests and needs can help in developing a collection that serves these needs. Faculty liaison activities also include attending academic departmental meetings and special events as a representative of the library, regular meetings with department chairs and library-faculty liaison groups, meeting with new faculty members and informing them about library collection and services, creating mailing lists and making regular announcements of library activities and new arrivals, updating information on library’s websites and newsletter, creating electronic discussion lists, blogs and RSS feeds to share information about new resources, recent acquisitions, library programs etc. Aiou Solved Assignments code 5646 ,
AIOU Solved Assignments Code 5646 Autumn 2019
Q.4 What do you understand by networking cables? Discuss major types of networking cables with examples.
Networking cables are networking hardware used to connect one network device to other network devices or to connect two or more computers to share printers, scanners etc. Different types of network cables, such as coaxial cable, optical fiber cable, and twisted pair cables, are used depending on the network’s physical layer, topology, and size. The devices can be separated by a few meters (e.g. via Ethernet) or nearly unlimited distances (e.g. via the interconnections of the Internet).
There are several technologies used for network connections. Patch cables are used for short distances in offices and wiring closets. Electrical connections using twisted pair or coaxial cable are used within a building. Optical fiber cable is used for long distances or for applications requiring high bandwidth or electrical isolation. Many installations use structured cabling practices to improve reliability and maintainability. In some home and industrial applications power lines are used as network cabling.
Despite advances in wireless technologies, many computer networks in the 21st century still rely on cables as a physical medium for devices to transfer data. Multiple different standard types of network cables exist, each designed for specific purposes.
Invented back in the 1880s, “coax” was best known as the kind of cable that connected television sets to home antennas. Coaxial cable is also a standard for 10 Mbps Ethernet cables. When 10 Mbps Ethernet was most popular, during the 1980s and early 1990s, networks typically utilized one of two kinds of coax cable – thinnet (10BASE2 standard) or thicknet (10BASE5). These cables consist of an inner copper wire of varying thickness surrounded by insulation and other shielding. Their stiffness caused network administrators difficulty in installing and maintaining thinnet and thicknet.
Twisted Pair Cables
Twisted pair eventually emerged during the 1990s as the leading cabling standard for Ethernet, starting with 10 Mbps (10BASE-T, also known as Category 3 or Cat3), later followed by improved versions for 100 Mbps (100BASE-TX, Cat5 and Cat5e) and successively higher speeds up to 10 Gbps (10GBASE-T). Ethernet twisted pair cables contain up to 8 wires wound together in pairs to minimize electromagnetic interference. Two primary types of twisted pair cable industry standards are defined – Unshielded Twisted Pair (UTP) and Shielded Twisted Pair (STP). Modern Ethernet cables use UTP wiring due to its lower cost, while STP cabling can be found in some other types of networks such as FDDI.
Instead of insulated metal wires transmitting electrical signals, fiber optic network cables work using strands of glass and pulses of light. These network cables are bendable despite being made of glass. They have proven especially useful in wide area network (WANs) installations where long distance underground or outdoor cable runs are required and also in office buildings where a high volume of communication traffic is common.
Two primary types of fiber optic cable industry standards are defined – single-mode (100BaseBX standard) and multimode (100BaseSX standard). Long-distance telecommunications networks more commonly use single-mode for its relatively higher bandwidth capacity, while local networks typically use multimode instead due to its lower cost.
Most Universal Serial Bus (USB) cables connect a computer with a peripheral device (keyboard or mouse) rather than to another computer for networking. However, special adapters (sometimes called dongles) also allow connecting an Ethernet cable to a USB port indirectly. USB cables feature twisted-pair wiring.
Serial and Parallel Cables
Because many PCs in the 1980s and early 1990s lacked Ethernet capability, and USB had not been developed yet, serial and parallel interfaces (now obsolete on modern computers) were sometimes used for PC-to-PC networking. So-called null model cables, for example, connected the serial ports of two PCs enabling data transfers at speeds between 0.115 and 0.45 Mbps.
Null modem cables are one example of the category of crossover cables. A crossover cable joins two network devices of the same type, such as two PCs or two network switches.
The use of Ethernet crossover cables was especially common on older home networks years ago when connecting two PCs directly together. Externally, Ethernet crossover cables appear nearly identical to ordinary (sometimes also called straight-through), the only visible difference being the order of color-coded wires appearing on the cable’s end connector. Manufacturers typically applied special distinguishing marks to their crossover cables for this reason. Nowadays, though, most home networks utilize routers that have built-in crossover capability, eliminating the need for these special cables.
Other Types of Network Cables
Some networking professionals use the term patch cable to refer to any kind of straight-through network cable being used for a temporary purpose. Coax, twisted pair and fiber optic types of patch cables all exist. They do not differ in physical characteristics from other types of network cables except that they tend to be a shorter length.
Powerline network systems utilize a home’s standard electrical wiring for data communication using special adapters plugged into wall outlets. Aiou Solved Assignments code 5646 ,
AIOU Solved Assignments Code 5646
Q5: Write notes on the following:
i. Wireless transmission
Wireless transmission is a form of unguided media. Wireless communication involves no physical link established between two or more devices, communicating wirelessly. Wireless signals are spread over in the air and are received and interpreted by appropriate antennas.
When an antenna is attached to electrical circuit of a computer or wireless device, it converts the digital data into wireless signals and spread all over within its frequency range. The receptor on the other end receives these signals and converts them back to digital data.
A little part of electromagnetic spectrum can be used for wireless transmission.
ii. OSI (ISO 7498) model
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work.
In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1. Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote.
International Standard ISO/IEC 7498-1 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology, in collaboration with ITU-T. The identical text is published as ITU-T Recommendation X.200.
This second edition, along with parts 2, 3 and 4, cancels and replaces the first edition (ISO 7498:1984), which has been technically revised.
ISO/IEC 7498 consists of the following parts, under the general title Information technology — Open Systems Interconnection — Basic Reference Model:
- — Part 1: The Basic Model
- — Part 2: Security Architecture
- — Part 3: Naming and addressing
- — Part 4: Management framework
Annex B forms an integral part of this part of ISO/IEC 7498. Annex A is for information only.
Web browsers receive HTML documents from a web server or from local storage and render the documents into multimedia web pages. HTML describes the structure of a web page semantically and originally included cues for the appearance of the document.
HTML elements are the building blocks of HTML pages. With HTML constructs, images and other objects such as interactive forms may be embedded into the rendered page. HTML provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists, links, quotes and other items. HTML elements are delineated by tags, written using angle brackets. Tags such as and directly introduce content into the page. Other tags such as surround and provide information about document text and may include other tags as sub-elements. Browsers do not display the HTML tags, but use them to interpret the content of the page. Aiou Solved Assignments code 5646 ,
iv. VPN (virtual private network)
A virtual private network (VPN) extends a private network across a public network, and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network. Applications running on a computing device, e.g. a laptop, desktop, smartphone, across a VPN may therefore benefit from the functionality, security, and management of the private network. Encryption is a common though not an inherent part of a VPN connection.
VPN technology was developed to allow remote users and branch offices to access corporate applications and resources. To ensure security, the private network connection is established using an encrypted layered tunneling protocol and VPN users use authentication methods, including passwords or certificates, to gain access to the VPN. In other applications, Internet users may secure their transactions with a VPN, to circumvent geo-restrictions and censorship, or to connect to proxy servers to protect personal identity and location to stay anonymous on the Internet. However, some websites block access to known VPN technology to prevent the circumvention of their geo-restrictions, and many VPN providers have been developing strategies to get around these roadblocks. Aiou Solved Assignments code 5646 ,