The Advantages and Disadvantages of Fiber Optic Cable vs. Coaxial Cable

Introduction Wires play an important role in transmitting electrical energy and signals between different locations. There are different types of wires that vary from one another depending on their characteristics and other physical aspects. This paper seeks to discuss the differences between fibre optic cables and coaxial cables, elaborating on the advantages and disadvantages of each type.Advertising We will write a custom essay sample on The Advantages and Disadvantages of Fiber Optic Cable vs. Coaxial Cable specifically for you for only $16.05 $11/page Learn More Fiber Optic Cable A fiber optic cable consists of either a plastic or a glass core, which conveys light enclosed within a glass cladding. Light is guided through the fibre owing to the lower refractive index of the material as it also reflects the escaping light to the core (Higuera, 1998). Advantages of fiber optic cables Fibre optic cables have limited signal loss for every unit distance c overed. In this regard, this type of cables can cover long distances and have limited effect on the quality of transmission. With high internet speeds being a factor for consideration in the contemporary world, fiber optic cable is more reliable because of its maintenance of the signal. Fibre optic cables have very high capacity, which means they can convey high data rates at any given time. Because of the cable’s technology that uses light, the cable is also able to transmit at high speeds. This makes it more reliable and efficient over other cable types. Fiber optic cables are also immune to external interference, which improves further on their reliability. Vibrations and other noises have little effect on the performance of the cable (Higuera, 1998). Disadvantages These cables are expensive compared to other types of cables. The materials used in the manufacture of fibre optic cables are costly and only made-to-measure. This is particularly typical of any new technologies (Higuera, 1998). The general vulnerability of fibre optic cables to strain and temperatures affects the performance quality of this type of cables. This affects the output signals because of the inherent errors (Higuera, 1998).Advertising Looking for essay on other technology? Let's see if we can help you! Get your first paper with 15% OFF Learn More Coaxial Cable Coaxial cables comprise of a core wire, as well as an interwoven foil material that covers the inner wire (Reynders, Mackay Wright, 2005). An insulating material that covers the central lying wire separates these conducting materials. Another insulator covers the outer foil. Advantages of coaxial cables This cable is cheaper than the fibre optic cable and, thus, it is highly affordable. Most mid-size offices and residential areas are able to acquire this cable for their internet needs. Coaxial cables can be used for different purposes. This increases their overall usefulness. Among the numerous uses of this type of cable include transmitting voice, data, as well as video signals. The cables are also easy to install around buildings (Reynders, Mackay Wright, 2005). Disadvantages of Coaxial Cables Coaxial cables are damaged easily. This affects the convenience aspect, while also adding costs in terms of repairs and new acquisitions. Installing thick coaxial cable is an expensive exercise, particularly where it is required to be pulled in between existing cable conduits. Coaxial cables work with connectors, which can be costly to acquire (Reynders, Mackay Wright, 2005). Conclusion Fibre optic and coaxial cables are used in performing the same roles, especially in transmitting data and signals. Their use has mainly increased with the advent of the internet. Fiber optic cables can carry large capacity of data at very high rates. They are also least affected by external interferences, such as noise or vibration. Coaxial cables, on the other hand, are less expensive and can easily be worke d with during installation. However, fiber optic cables are expensive to acquire and vulnerable to stress interference. Coaxial cables on their part are susceptible to damages and their thicker versions are difficult to install. References Higuera, J. M. L. (1998). Optical sensors. Cantabria: Ed. Universidad de Cantabria.Advertising We will write a custom essay sample on The Advantages and Disadvantages of Fiber Optic Cable vs. Coaxial Cable specifically for you for only $16.05 $11/page Learn More Reynders, D, Mackay, S. Wright, E. (2005). Practical industrial data communications: Best practice techniques. Burlington, MA: IDC Technologies. This essay on The Advantages and Disadvantages of Fiber Optic Cable vs. Coaxial Cable was written and submitted by user Ethan M. to help you with your own studies. You are free to use it for research and reference purposes in order to write your own paper; however, you must cite it accordingly. You can donate your paper here.

Print-On-Demand vs Offset Printing Which Is Better (with Examples)

Prints) Print-On-Demand vs Offset Printing: Which Wins? This is a guest post by Jessica Ruscello, a copywriter at Blurb, Inc. Jessica is also a writer, teacher, and photographer who makes her mark with empty coffee cups, ink spills, and red lipstick.The last ten years- even the last five- have seen game-changing developments in printing technology. Even if print-on-demand has been around longer than that, we’re now seeing these digital machines produce exquisite quality (depending on which service you use). Advanced inkjet technology now creates pages and covers that are nearly identical to those created with traditional offset printing, offering incredible advantages to self-publishers.How can you make sure you're getting the most return out of it? Let's find out.How print-on-demand works (in 6 steps)Choose your format. From coffee-table books to magazines to trade paperbacks, print-on-demand is compatible with any format you’d find in a bookstore. The more copies you order, the more cost-effective customization becomes (hi gher volume order makes it possible to try different endsheets, ribbon markers, or cover styles). That said, standard commercial sizes and papers are readily available across printers.Create a properly formatted book file. Your PDF (or another print-ready file) will stay with the printer and can be called up any time an order is placed for your book.List your book on major bookselling sites. You can do this using a â€Å"print-on-demand distributor† like KDP Print (for Amazon), IngramSpark, or Blurb.Every time someone orders your book, the order is sent to the printer. Digital printers print and assemble your book all in one place.The book is shipped to the retailer, who forwards it to your reader. In some cases, the customer will be able to get the print book in under one hour!Your reader pays the retailer. Your retailer will then send the net revenue to you (after deducting printing costs and retailer discounts- read more about these below). 100+ Client Services Pricing - $16.00/copy (Not including taxes or shipping) 1000 Copies Offset Printing - $7.50 /copy (Includes approximate shipping to US)Don’t overlook offset printing because of the large upfront costs, and don’t overlook print-on-demand, which offers greater speed, quality, and innovation than what has been available at any other time in print history. Whichever one's better for your project, there's no doubt that print-on-demand has done so many exciting things for book-makers, creating more options for beautiful end products.Have you tried offset printing on one of your books? What has been your experience with print-on-demand so far? Leave your thoughts (as well as any questions for Jessica) in the comments below.

Based on your reading of The Death of Woman Wang,describle and analyze Essay

Based on your reading of The Death of Woman Wang,describle and analyze how Confucian ideals are ever present to all levels of Ch - Essay Example According to Confucius, society could become stable only when the five basic relationships are being fulfilled which are, the relation of Love (among father and son), relationship of righteousness (among emperor and minister), relationship of virtuous demeanor (among husband and wife), relationship of order (among elder and younger) and relationship of faithfulness (among friends).If we closely administer these virtues, we see that out of the five, three occur in the family system. He was the great devotee of the family system and it is also the basis of today’s family system in China (Spence pp134-139). The family system has an extended impact on the whole town, city and society of China. The order is strictly followed as, for instance, younger has to obey the elder whether the elder is from his family or from outside the family. Even today, Chinese people pay special respect to their elders (Spence pp 74-96). The death of woman Wang is a piece of literature that provides a h igh exposure to Chinese norms, society and cultural values back in the seventeenth century. According to Spence, the obligation of the people to the government is very high. To support the government, they have to pay taxes. Even when there were natural calamities, the people of the village had to pay taxes. The rule of the emperor is to be judged by the virtue and it is not hereditary. According to Confucius, the ruler must rule wisely and with moral attitudes. The ruler should be just in his working and virtue must be his core conduct. If the society is being ruled by a wise and just leader and ruler, the society is harmonized, stable and flourishing and it cultivates moral and ethical values. When the government understood the condition of the village, firstly they divided the tax in installments and later on forgave the taxes to be paid. But it was too late (Spence pp 33-58). The modern Chinese society is prospering mainly due to the autonomy that their political system provides . Chinese production market, for instance, is growing at a remarkable pace. The government provides the basic necessities to their citizens at low costs. The rulers, hence, are following the principles of Confucius wisely and with high moral attitude. Conscious considered woman as morally and intellectually defective. He was the strong opponent of women subordination. Regardless of this fact, the principles he provided were significantly influential in maintaining harmony, peace and stability in an economy. In ‘the story of woman Wang’ women are portrayed as liable to perform household chores. As a widow, they are given high value and respect if they remain loyal to their husbands even after he passes away. Women are severely punished, in Spence’s accounts, if they use their right to freely move around, choose their partners or try to change their lives. They are punished and eventually killed by one or the other men in Chinese society of 17th century. However, t he modern Chinese society regards female counterparts as respectful, loveable and respectful yet free to make choices. The Chinese society and the business market is an open case of female participation except households. The households and other family related issues, however, still work under women supervision and women are still held responsible for household works. Filial Piety is yet another value of Confucius. Confucius is also heard of saying â€Å"

Strategic Management (M&S strategic analysis) Essay

Strategic Management (M&S strategic analysis) - Essay Example To maintain this, the company needs to develop a strategy that will take into consideration all the factors that might affect the sales of the company (Prince, M. 2012, 23). The aim of this essay is to determine all the factors that might affect the sales of each of the products of Marks and Spencer and come up with the most relevant strategy to help the company reach its goal. In an institution that relies on the will of a customer in a big part like Marks and Spencer, it would be prudent to have a plan that takes into consideration most of the needs of the customer (Worth, R. 2007, 62). This is just one of the needs that the company should take into consideration. For maximum productivity, the company must evaluate each of the PESTEL factors. This is to avoid being in trouble with the administration and other bodies. The company should make sure that its waste is not harmful to the environment. A big company like Marks and Spencer could easily bring catastrophic damages to the environment. The fact that it is widely over Europe, which makes it very visible, and the public is very conscious of what they do. If the company started destroying the environment, it would be seen by everyone, and this would lead to them loosing the trust and love of the customer (Marketing Society. 2009, 15). The company should also take into consideration the international tie s between the various countries that they operate in. It should follow the rules of the country to the latter. The other issue that the company should consider is how they treat their staff. A general well treatment of the members of a certain company brings a general improvement of output among the workers. This, in return, is beneficial to the company since they get products of better quality. The company should also take into huge consideration their competitors and the range of services that they offer.

Sunset Boulevard as a Genre Film Essay Example | Topics and Well Written Essays - 2000 words

Sunset Boulevard as a Genre Film - Essay Example Many critics argue as to whether noir is a genre or a sub-genre. As Martin Scorcese says in one his documentaries, noir is a sub-genre of drama and doesn’t have any unique definition. Filmmakers like him say that term noir is just a term that is used to indicate certain stylistic elements which are common in the movies of 1940s and 1950s. In the wake of this dilemma among the critics, this essay puts forward a hypothesis that identifies itself with the claim of many film critics that it a noir movie. In this essay, the movie shall be tested against the framework of conventional noir movie making and an analysis shall be made about the genre of the movie. The analysis shall be comprehensive and include detailed examples from the movie and also various secondary sources of information. Sunset Boulevard is widely regarded as a cult movie and one of the epic movies belonging to the noir genre. First of all, it is important to establish what is a noir genre and how did it develop in Hollywood. During the 1930s many artists, directors, and composers were ousted from Germany by Hitler. These people came to Hollywood and started to work there. The political and social situation of Germany instilled in them a sense of cynicism. It is a known fact that the German government at that time was involved in the systematic killing of millions of people. This cynicism and pessimism was carried forward and brought to Hollywood. The German Expressionist cinema, when combined with the Hollywood’s fascination with crime, created a genre called noir. This term was not used at that time but was later coined by critics in the 1970s to describe a kind of films that were made in the 1940s and 1950s.

SHCBK Protocol for Securing Ad Hoc Networks

SHCBK Protocol for Securing Ad Hoc Networks Abstract With present advances in technology, wireless networks are getting more popularity. These networks let the users the liberty to travel from one location to another without disruption of their computing services. The Ad-hoc networks, are the subset of wireless networks, let you the configuration of a wireless network without the require for access point. Technology under development for wireless ad hoc networks has quickly become a crucial part of our life since it provides â€Å"anytime, anywhere† networking services for mobile users. Wireless ad hoc networks can be dynamically set up without relying on any pre-existing infrastructure, such as Public Key Infrastructure, and central management for communications. However, such infrastructure-less characteristic of the networks also makes them vulnerable to security attacks. Numerous protocols have been planned in order to attain a high degree of safety based on a mixture of human-mediated communication and an normal Dolev-Yao c ommunication medium. One of which is the Symmetrised Hash Commitment Before Knowledge protocol or the SHCBK protocol ( A. W. Roscoe and Long Nguyen, 2006). The protocol design seeks to optimise the amount of security that the humans can attain for a known quantity of work. This dissertation presents an implementation of the SHCBK protocol for securing ad hoc networks over Wi-Fi. Chapter 1 Introduction A wireless ad hoc network is a de-centralized wireless network. The network is called ad hoc for the reason that each hop is ready to send onward data for other hop, and so the resolving that which of hops will send the data to the forward hops is dynamically established on the network connectivity. This is in dissimilarity to wired networks in which routers execute the duty of routing. It is also in difference to organize the wireless networks. In which a particular node recognized as an admission point manages communication among other nodes. All taking part parties in an ad hoc network have the same opinion to recognize and send onward messages, to and from each other. With this type of elasticity, wireless networks have the capability to form anyplace, at any occasion, as long as two or more wireless users are enthusiastic to have the communicate between them. Mobile nodes inside an ad-hoc network move from one location to another. However, finding ways to model these movements i s not obvious. In order to evaluate an ad hoc network performance it is necessary to develop and use mobility models that accurately represent movements of the mobile nodes. In this paper we present performance evaluation of various entity mobility models in terms of the traveling patterns of mobile node. MANET is a self-configuring network that is formed automatically via wireless links by a collection of mobile nodes without the help of a fixed infrastructure or centralized management. The mobile nodes forward packets for each other, allowing communication among nodes outside wireless transmission range hop by hop. Due to dynamic infrastructure-less nature and be deficient in the centralized monitoring points, the ad hoc networks are susceptible to attacks. The Attacks on the ad- hoc network routing protocols can disturb the network performance and dependability. Wireless networks use radio waves to broadcast the signals and survive in essentially two dissimilar flavors, communica tions and ad-hoc. In communications mode all traffic is transmitted among The HOPs via an admission point which controls the network and gives it with the safety system. The most usually used normal for wireless networks is the 802.11 principles or Wi-Fi which in fact is not a standard but a entire relatives of principles using the same protocol. The safety in wireless networks by Wi-Fi consists of WEP, WPA and now lately WPA2 which is essentially a ended version of WPA. WPA was shaped as an middle safety system while WPA2 was finalized and experienced since the preceding system contained several serious weaknesses. Benefits and applications of ad-hoc Networks Ad-hoc networking need not want any admission points as contrasting to wireless networks in Communications mode. This makes them functional in a set of diverse applications. It is mainly used in Military applications and in save operations where the accessible communication communications Has been damaged or is unavailable, for example later than earthquakes and other disasters. But ad-hoc is these days also being used in a lot of commercial applications. Like we see that mobile phones and PDAs using the Bluetooth protocol system, seeing as it is quick and fairly simple to setup and doesnt need any additional tools. Characteristics and standards of ad-hoc As the wireless standard 802.11 does hold up ad-hoc networks, it is extremely limited since it doesnt offer routing among the nodes, so a hop can only arrive at the straight noticeable nodes in its place protocols similar to the Ad-hoc, On-demand Distance Vector protocol or Dynamic Source Routing protocol can not be used. These routing protocols are so called immediate routing protocols, sense that it gives a route to a target only when wanted. In difference the other usually used routing protocols on the Internet are practical sense that they will set up routes separately of the traffic in the network. This implies that the reactive network is quiet pending a connection that is wanted and thus lessens the overcrowding in the network. DSR is an even additional optimized protocol which doesnt need for the sending forwarding computers to have current routing tables but have a list of network addresses in the form of the packet. The protocol because of eavesdrops the limited network traffic and listens for this routing data and information included in the packets and adds it to its personal routing table. One of the major goals when scheming mobile ad-hoc networks where the nodes go about and the topology rapidly alters is to defend the network connectivity among the hops over potentially multi hop channels. To obtain multi hop connection you must offer one-hop connectivity throughout the link-layer and expand that to multi- hop connectivity throughout routing and data that is forwarding protocols in the network-layer. Many corporations make substantial investments in their wire- less infrastructure. For example, Microsofts IEEE 802.11 based Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy or else, to republish, to position on servers or to redistribute to lists, requires prior specific permission and/or a fee. Wireless (Wi-Fi) network consists of approximately 5,000 access points (APs) supporting 25,000 users each day in 277 buildings, covering more than 17 million square feet [10]. In addition to the equipment costs, the costs of planning, deploying, and maintaining such networks is substantial. Thus, it is important to develop infrastructure that improves the ability of Information Technology (IT) departments to manage and secure their wireless networks. In recent years, researchers have uncovered security vulnerability- ties in Wi-Fi networks [20]. They showed that the Wired Equiv- agency Protocol (WEP), the popular 802.11 security mechanism that most corporations were using at the time, was fundamentally flawed. In a series of highly publicized papers, they showed that 802.11 networks could be compromised easily. The community reacted quickly by developing and deploying alternate security so- lotions including VPNs, IEEE 802.1x [30], several variations of EAP [14], Smart cards, and more recently WPA [29]. Yet, the wire- less LAN (WLAN) security problem was not completely resolved. Last year, Microsoft conducted a series of interviews with WLAN administrators of several large and small organizations [10]. The goal of these interviews was to understand the difficulties involved in deploying and managing corporate WLANs. The issue of WLAN security came up repeatedly during these interviews. All administrators felt that WLAN security was a problem. They were unhappy with the quality of the tools they had at their disposal. Many of them would periodically walk around their buildings using WLAN scanning software looking for security vulnerabilities. Some hired expensive outside consultants to conduct security vulnerability analyses of their WLAN deployme nt, only to conclude that what they really needed was an on-going monitoring and alerting system. Most administrators believed that better systems to manage WLAN security are needed. Even after protocols such as IEEE 802.1x and WPA are deployed, corporate networks can be compromised by off-the-shelf 802.11 hardware and software. For example, an unauthorized AP can be connected to the corporate Ethernet, allowing unauthorized clients to connect to the corporate network. The rogue AP may be con- nected by a malicious person or, as is more often the case, by an employee who innocently connects an AP in his office without realizing that he is compromising the corporate network. A rogue AP can circumvent the elaborate security measures that the IT department may have put in place to protect the companys intellectual property. To test our assertion that people inadvertently compromise the security of their networks, we conducted an experiment in two large organizations that had secured their WLANs using one of the methods mentioned previously. We walked around with a WLAN- enabled laptop in a small section of the two campuses looking for APs to which we could connect. Chapter 2 SECURITY ATTACKS Here I attempts to provide a comprehensive overview of attacks and secure routing. It first analyzes the reason that ad hoc network is vulnerable to attacks. Then it presents the well known attacks and the popular secure protocols. Is out of its radio range, the cooperation of other nodes in the Network is needed. This is known as multi-hop communication. Therefore, each node must do something as both a host and a router at the same time. In most wireless networking environments in productive use today the users devices communicate either via some networking infrastructure in the form of base stations and a backbonenetwork,ordirectlywiththeirintended communication partner, e.g. by means of 802.11 in ad hoc networks In distinction a mobile ad-hoc network is a self-configuring network that is formed automatically via wireless links by a collection of mobile nodes without the help of a fixed infrastructure or centralized management. Every hop in the mobile ad-hoc networks is ready with a wireless transmitter and receiver, which allow it to communicate with other nodes in its radio communication area. Hops are more often share the same physical media. They broadcast and obtain signals at the same frequency band, and chase the same hopping series or spreading code. If the purpose node is not inside the broadcasting range of the sending node, then the sending node takes help of the intermediate hops to communicate with the purpose node by relaying the messages hop by hop. Fig.2 describes the Mobile ad-hoc network. In order for a node to forward a packet to a node that TYPES OF THE SECURITY ATTACKS Securing wireless ad hoc networks is a highly demanding issue. Due to dynamic scattered infrastructure-less nature and be deficient in of centralized monitoring points, the ad hoc networks are susceptible to a variety of attacks. Ad hoc networks have to manage with the same kinds of vulnerabilities as their wired counterparts. As well as with new vulnerabilities specific to the ad hoc context. In addition, conventional vulnerabilities are also accentuated by the ad hoc paradigm. Initially, the wireless channel is available for the both genuine network users and cruel attackers. The ad hoc networks are vulnerable to attacks ranging from static eavesdropping to active prying. Secondly, the be short of an online CA or Trusted Third Party adds the complexity to organize security mechanisms. Thirdly, mobile devices be inclined to have limited power consumption and calculation capabilities which make it more vulnerable to Denial of Service attacks and incapable to execute computation-heavy algorithms like public key algorithms Fourthly, in MANETs, therearemore probabilities for trusted node being compromised and then life form used by adversary to launch attacks on networks. Lastly, node mobility and recurrent topology changes enforce frequent networking reconfiguration which creates more chances for attacks, for example, it is difficult to discriminate between stale routing information and faked routing information. Ad -hoc networks attacks can be differentiated as passive and active. Passive attack signifies that the assailant does not send any message, but just listens to the channel. Passive attacks do not disturb the process of a protocol, but only makes the attempts to find out valuable information. Active attacks may either being directed to disturb the normal operation of a exact node or target the performance of the ad hoc network as a whole. For passive attacks, the attacker listens to the channel and packets that are containing clandestine information might be eavesdropped, which violates privacy. In a wireless environment it is usually not possible to notice this attack, as it does not create any new traffic in the network. Active attacks, counting injecting packets to unacceptable destinations into the network, deleting packets, changing the contents of packets, and impersonating other hops infringe ease of use, veracity, verification, and non-repudiation. Different from the passive attacks, active attacks can be detected and ultimately avoided by the legal nodes that contribute in an ad hoc network . We broadly classify these attacks as passive and active. The classification is important for understanding the strengths and limitations of the DAIR security management system. Eavesdropping Eavesdropping is a passive attack. The attacker passively listens to the traffic on the wireless network and gleans useful information. The listener may use sophisticated code breaking techniques. Countermeasures include use of better encryption techniques as well as physical security measures such as use of radio-opaque wallpaper. Passive attacks are difficult, if not impossible, to detect and we do not address them in this paper. Intrusion Any attack that allows a user to gain unauthorized access to the network is called an Intrusion attack. Intrusion attacks are active attacks and several such attacks are possible. An attacker can compromise the corporate network by gaining physical access to its wired network and connecting a wireless AP to it. The AP creates a â€Å"hole† through which unauthorized clients can connect, bypassing the elaborate security measures that the IT department may have put in place. A similar attack can be carried out by using ad-hoc wireless networks instead of APs. A corporate network may also be compromised when an attacker finds and uses an unsecured AP connected to the network by an unsuspecting employee. The widespread availability of inexpensive, easy-to- deploy APs and wireless routers has exacerbated this problem. As mentioned earlier, we found several unsecured APs in large organizations. The DAIR security management system can detect both rogue APs and rogue ad-hoc networks. Another way a corporate network can be compromised is when an attacker obtains the credentials (e.g., WEP passwords, IEEE 802.1x certificates) needed to connect to the corporate ne twork. The DAIR security management system can not currently detect such attacks. Denial of Service (DoS) Denial of Service attacks are active attacks. A diversity of DoS attacks are possible. Some DoS attacks exploit flaws in the IEEE 802.11 protocol. For example, a disassociation attack is where the attacker sends a series of fake disassociation or deauthentication messages, causing legitimate clients to disconnect from the AP. In a NAV attack, the attacker generates packets with large duration values in the frame header, thereby forcing legiti- mate clients to wait for long periods of time before accessing the network . In a DIFS attack, the attacker exploits certain timing- related features in the IEEE 802.11 protocol to aggressively steal bandwidth from legitimate users. In all three cases, the attacker transmits packets in an abnormal way, either by generating non-compliant packets, or by transmitting compliant packets at an abnormally high rate. The DAIR security management system can detect such attacks. DoS attacks are also possible by creating large amount of RF noise in the ne ighborhood of the network. The DAIR security management system can detect such attacks by comparing current observations with historical data observed from multiple vantage points. DoS attacks can also be mounted by gaining access to the corporate wired network and attacking the APs from the wired side. The DAIR system does not handle DoS attacks on the wired network. Phishing Phishing is an active attack. An attacker sets up a wireless AP that masquerades as a legitimate corporate AP (same SSID, per- haps even same BSSIDs). If the client does not use mutual authentication, it is possible for the attacker to lure unsuspecting legiti- mate users to connect to its AP. The attacker can then use a variety of techniques to extract private information (for example, sniff for passwords). The DAIR system can detect phishing attacks. How- ever, we do not describe solutions to phishing attacks in this paper. ACTIVE ATTACKS SECURITY ATTACKS Certain active attacks can be easily performed alongside an ad -hoc network. Understanding possible shape of attacks is for all time the first step towards increasing good safety solutions. Based on this danger analysis and the recognized capabilities of the potential attackers, several well recognized attacks that can target the operation of a routing protocol in an ad hoc network are discussed. Impersonation. In this kind of attack, nodes may be clever to join the network untraceable or can able to send the false routing data/information, camouflaged as some other trusted node. Wormhole. The wormhole attack involves the collaboration stuck between two attackers. One attacker gets the routing traffic at one point of the network and changes their path to another point in the network that shares a confidential communication link between the attackers, then selectively injects tunnel traffic back into the network. The two colluding assailant can potentially deform the topology and set up routes under the control over the wormhole link. Rushing attacks: The ROUTE REQUESTs for this Discovery sanded forwarded by the attacker can be the 1st to approach each neighbor of the target, then any way exposed by this Route Discovery will comprise a hop through the attacker. That is, when a neighbor of the target gets the hurried REQUEST from the attacker, and it forwards that REQUEST, and will not send onward any further REQUESTs from this Route Discovery. When non-attacking REQUESTs arrive later at these nodes, they will discard those legitimate REQUESTs. Blackmail: The attack incurs outstanding to be short of of genuineness and it grants stipulation for any node to corrupt other nodes legal information. Hops more often keep the data/ information of apparent malevolent nodes in a blacklist. This attack is pertinent alongside routing protocols that use mechanisms for the recognition of malicious nodes and spread messages that try to blacklist the criminal. An attacker may make such coverage messages and tell other nodes in the network to put in that hop to their blacklists and cut off legitimate nodes from the network. Chapter 3 Secure Routing The previously presented ad hoc routing protocols with no security contemplation assume that all participating nodes do not maliciously troublemaking the operation of the protocol. However, the continuation of malicious entities cannot be unnoticed in any system, particularly in open ones like ad hoc networks. Safe routing protocols manage with malicious nodes that can disturb the right performance of a routing protocol by changing routing information. By fabricating the wrong routing data or information and by impersonating other nodes. These safe routing protocols for ad hoc networks are either totally new stand-alone protocols, or in some cases incorporations of security mechanisms into obtainable protocols. Generally the obtainable safe routing protocols that have been future can be generally secret into two types, those that use hash chains, and those that in order to function require predefined trust relations. This method, jointly nodes can efficiently validate the legitimate traffic and distinguish the unauthenticated packets from outsider attackers. ROUTING PROTOCOL FOR AD-HOC NETWORK SECURITY SEAD: Safe Efficient Ad hoc Distance-vector routing protocol. A safe ad hoc network routing protocol that is established on the design of the Destination Sequenced Distance Vector routing protocol. To hold up employ of SEAD with hops of partial CPU processing abilities, and to guard against modification of the source address for a routing update and attacks in which an rejection of service attacks makes attempts to reason other nodes to use surplus network bandwidth or processing time of the network, efficient one way hash Chains but not cryptographic operations are used in the verification of the series number and the metric field of a routing table update message. When a node in SEAD sends a routing update, the node includes one hash value from the hash chain with each entry in that update. The nodes sets the purpose address in that entry to that target nodes address, the metric and series number to the values for that target in its routing table, and the hash value to the hash of the hash value conventional in the routing update entry from which it learned that route to that destination. When a node receives a routing inform, for each entry in that update, the node checks the verification on that entry, by the target address, sequence number, and metric in the conventional entry, together with the newest prior genuine hash value established by this node from that destinations hash chain. The hash value of each entry is hashed the right number of times and it is compared to the before authenticated v alue. Depending on this contrast the routing update is either established as authenticated, or discarded. Ariadne; Ariadne is a safe on-demand ad hoc routing protocol based on DSR that restricts attackers or the mutual hops from tampering with uncompromised routes containing of uncompromised hops, and also stops a lot of types of DOS attacks. In addition, Ariadne uses only extremely well-organized symmetric cryptographic primitives. To induce the objective of the authority of each field in a ROUTE REQUEST, the originator simply includes in the REQUEST a MAC computed with key over exclusive data. The object can with no trouble corroborate the authenticity and newness of the ROUTE REQUEST using the shared key. One-way hash functions are use to confirm that no hop was absent which is called per hop hashing. Three alternative methods to attain hop list verification. The TESLA protocol, digital signatures, and typical MACs. When Ariadne Route detection is used with TESLA, every node authenticates the original data in the REQUEST. The objective buffers and does not fire the REPLY awaiting midd le nodes can discharge the matching TESLA keys. Ariadne Route Discovery using MAC is the majority well-organized way of the three option verification mechanisms, but it asks couple wise communal keys among all nodes. The MAC list in the ROUTE REQUEST is computed by a key common among the object and the present node. The MACs are verified at the target and are not returned in the ROUTE REPLY. If Ariadne way detection is used with digital signatures, the MAC list in the ROUTE REQUEST becomes a signature list. SRP: The safe Routing Protocol consists of quite a lot of safety extensions that can be practical to existing ad hoc routing protocols as long as end-to-end verification. The one and only requirement of the future scheme is the sustained existence of a security association between the node initiating the query and the sought destination. The safety association is used to found a common secret between the two nodes, and the non mutable types of the exchanged routing messages are confined by this shared secret. The method is robust in the occurrence of a number of non-colluding nodes, and provides Routing Table Overflow: In a routing table spread out attack the malevolent node floods the network with bogus route formation packets to non existing nodes to overpower the routing protocol implementations in order to devour the resources of the participating nodes and interrupt the establishment of legal routes. The goal is to create enough routes to prevent new routes from being created or to engulf the protocol execution. Proactive routing protocols are more vulnerable to this attack, since they attempt to produce and preserve routes to all possible destinations. A spiteful node to apply this attack can simply send unnecessary route advertisements to the network. To apply this harasses in order to target a reactive protocol like AODV is to some extent more involved since two nodes are obligatory. The first node should make a genuine request for a route and the malicious node should reply with a forged address. Sleep Depravation: The sleep scarcity afflict aims at the utilization of store of a specific node by constantly keeping it busy in routing decisions. This attack floods the network with routing traffic in order to munch through battery life from the nodes and accessible bandwidth from the ad hoc network. The malicious node continually requirements for either existing or non-existing destinations forces the neighboring nodes to procedure and forward these packets and therefore munch through batteries and network bandwidth hindering the normal operation of the network. Location disclosure: Location disclosure is an attack that targets the solitude necessities of an ad hoc network. Through the use of traffic analysis techniques or with simpler probing and monitoring methods an attacker is able to discover the location of a node, and the structure of the network. If the locations of some of the intermediary nodes are known, one can gain information about the location of the destination node as well. Routing table poisoning: Routing protocols uphold tables which hold information on the subject of routes of the network. In poisoning attacks the malevolent nodes create and send untrue traffic, or modify legitimate messages from other nodes, in order to create false entries in the tables of the participating nodes. One more option is injecting a RREQ package with a high sequence number. This will reason that all other legal RREQ packets with lower sequence number will be deleted. Routing table poisoning attacks can result in selection of non-optimal routes, creation of routing loops, bottlenecks and even partitioning sure parts of the network. Black Hole: A malicious node uses the routing protocol to insert fake route answers to the route needs it receives promotion itself as having the straight path to a target whose packets it needs to cut off. Once the fake route has been recognized the mean node is able to become a member of the lively route and intercept the communication packets. Network traffic is diverted through the malicious node for eavesdropping, or be a focus for all traffic to it in order to execute a DOS by dropping the received packets or the first step to a man-in-the-middle attack. While the safety requirements for ad hoc networks are the similar the ones for fixed networks, namely ease of use, privacy, reliability, validation, and non-repudiation mobile wireless networks are usually more susceptible to information and physical safety fears than fixed wired networks. Securing wireless ad hoc networks is chiefly tricky for many reasons as well as vulnerability of channels and nodes, nonattendance of communications, dynamically altering topology and etc.; The wireless channel is available to both legal network users and malicious attackers. The abstract of centralized management makes the traditional security solutions based on certification establishment and on-line servers unsuitable. A malicious attacker can willingly become a router and disturb network operations by deliberately disobeying the protocol specifications. The nodes can move arbitrarily and liberally in any way and systematize themselves arbitrarily. They can stick together or leave the network at any time. The network topology changes regularly, rapidly and randomly which considerably alters the status of trust among nodes and adds the complexity to routing among the mobile nodes. The egoism that nodes in ad hoc networks may tend to reject providing services for the advantage of other nodes in order to keep their own possessions introduces new security issues that are not address in the infrastructure-based network Chapter No 3 Distributed Security Scheme for Mobile Ad Hoc Networks In difference to fixed networks a central certification power is not possible in ad hoc networks. Distributing the functionality of certification power over number of nodes is a probable solution. This can be got by creating n shares for a clandestine key and distributing them to n different node. Key can be generating by combining the shares using doorsill cryptography methods. Mobile ad-hoc networks are extremely active. Topology differences and link crack occur fairly often. Therefore, we require a safety answer which is active, too. Any malicious or disobedient nodes can produce antagonistic attacks. These types of attacks can gravely injure essential aspects of safety, such as veracity, confidentiality and space to yourself of the node. Current ad-hoc routing protocols are totally unsure of yourself. Furthermore, obtainable safe routing mechanisms are either too luxurious or have impractical necessities. In ad hoc network, safety solution should separate the attackers and compro mised nodes in the network. Proactively dividing the attackers make it sure that they cannot carry on to attack and waste the network resources in future. A safety solution should have lessening transparency over. Attacks beside ad-hoc routing protocols can be categorize as active or passive. A passive attack does not upset the functioning of the protocol, but tries to discover valuable information by listening to traffic. An active attack inserts arbitrary packets and tries to upset the operation of the protocol in order to bound the accessibility, gain confirmation, or attract packets meant to other nodes. In ad hoc network disobedient node can advertise its accessibility. Nearby nodes changs its route table with the new route and ahead the packet through the disobedient node. Misbehaving node can alter or even drop the packet. So mobile nodes must be able to prove the reliability of a new neighbor before adding it to the route table. Also it is imperative to care for the data pac kets from eavesdropping. Once the cluster member link has reputable a secured link, they can further switch symmetric key and encrypt data packet to ensure data in private and integrity. CLUSTER-BASED TOPOLOGY Clustering is a method by which nodes are placed into groups, called clusters. A cluster head is designated for SHCBK Protocol for Securing Ad Hoc Networks SHCBK Protocol for Securing Ad Hoc Networks Abstract With present advances in technology, wireless networks are getting more popularity. These networks let the users the liberty to travel from one location to another without disruption of their computing services. The Ad-hoc networks, are the subset of wireless networks, let you the configuration of a wireless network without the require for access point. Technology under development for wireless ad hoc networks has quickly become a crucial part of our life since it provides â€Å"anytime, anywhere† networking services for mobile users. Wireless ad hoc networks can be dynamically set up without relying on any pre-existing infrastructure, such as Public Key Infrastructure, and central management for communications. However, such infrastructure-less characteristic of the networks also makes them vulnerable to security attacks. Numerous protocols have been planned in order to attain a high degree of safety based on a mixture of human-mediated communication and an normal Dolev-Yao c ommunication medium. One of which is the Symmetrised Hash Commitment Before Knowledge protocol or the SHCBK protocol ( A. W. Roscoe and Long Nguyen, 2006). The protocol design seeks to optimise the amount of security that the humans can attain for a known quantity of work. This dissertation presents an implementation of the SHCBK protocol for securing ad hoc networks over Wi-Fi. Chapter 1 Introduction A wireless ad hoc network is a de-centralized wireless network. The network is called ad hoc for the reason that each hop is ready to send onward data for other hop, and so the resolving that which of hops will send the data to the forward hops is dynamically established on the network connectivity. This is in dissimilarity to wired networks in which routers execute the duty of routing. It is also in difference to organize the wireless networks. In which a particular node recognized as an admission point manages communication among other nodes. All taking part parties in an ad hoc network have the same opinion to recognize and send onward messages, to and from each other. With this type of elasticity, wireless networks have the capability to form anyplace, at any occasion, as long as two or more wireless users are enthusiastic to have the communicate between them. Mobile nodes inside an ad-hoc network move from one location to another. However, finding ways to model these movements i s not obvious. In order to evaluate an ad hoc network performance it is necessary to develop and use mobility models that accurately represent movements of the mobile nodes. In this paper we present performance evaluation of various entity mobility models in terms of the traveling patterns of mobile node. MANET is a self-configuring network that is formed automatically via wireless links by a collection of mobile nodes without the help of a fixed infrastructure or centralized management. The mobile nodes forward packets for each other, allowing communication among nodes outside wireless transmission range hop by hop. Due to dynamic infrastructure-less nature and be deficient in the centralized monitoring points, the ad hoc networks are susceptible to attacks. The Attacks on the ad- hoc network routing protocols can disturb the network performance and dependability. Wireless networks use radio waves to broadcast the signals and survive in essentially two dissimilar flavors, communica tions and ad-hoc. In communications mode all traffic is transmitted among The HOPs via an admission point which controls the network and gives it with the safety system. The most usually used normal for wireless networks is the 802.11 principles or Wi-Fi which in fact is not a standard but a entire relatives of principles using the same protocol. The safety in wireless networks by Wi-Fi consists of WEP, WPA and now lately WPA2 which is essentially a ended version of WPA. WPA was shaped as an middle safety system while WPA2 was finalized and experienced since the preceding system contained several serious weaknesses. Benefits and applications of ad-hoc Networks Ad-hoc networking need not want any admission points as contrasting to wireless networks in Communications mode. This makes them functional in a set of diverse applications. It is mainly used in Military applications and in save operations where the accessible communication communications Has been damaged or is unavailable, for example later than earthquakes and other disasters. But ad-hoc is these days also being used in a lot of commercial applications. Like we see that mobile phones and PDAs using the Bluetooth protocol system, seeing as it is quick and fairly simple to setup and doesnt need any additional tools. Characteristics and standards of ad-hoc As the wireless standard 802.11 does hold up ad-hoc networks, it is extremely limited since it doesnt offer routing among the nodes, so a hop can only arrive at the straight noticeable nodes in its place protocols similar to the Ad-hoc, On-demand Distance Vector protocol or Dynamic Source Routing protocol can not be used. These routing protocols are so called immediate routing protocols, sense that it gives a route to a target only when wanted. In difference the other usually used routing protocols on the Internet are practical sense that they will set up routes separately of the traffic in the network. This implies that the reactive network is quiet pending a connection that is wanted and thus lessens the overcrowding in the network. DSR is an even additional optimized protocol which doesnt need for the sending forwarding computers to have current routing tables but have a list of network addresses in the form of the packet. The protocol because of eavesdrops the limited network traffic and listens for this routing data and information included in the packets and adds it to its personal routing table. One of the major goals when scheming mobile ad-hoc networks where the nodes go about and the topology rapidly alters is to defend the network connectivity among the hops over potentially multi hop channels. To obtain multi hop connection you must offer one-hop connectivity throughout the link-layer and expand that to multi- hop connectivity throughout routing and data that is forwarding protocols in the network-layer. Many corporations make substantial investments in their wire- less infrastructure. For example, Microsofts IEEE 802.11 based Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy or else, to republish, to position on servers or to redistribute to lists, requires prior specific permission and/or a fee. Wireless (Wi-Fi) network consists of approximately 5,000 access points (APs) supporting 25,000 users each day in 277 buildings, covering more than 17 million square feet [10]. In addition to the equipment costs, the costs of planning, deploying, and maintaining such networks is substantial. Thus, it is important to develop infrastructure that improves the ability of Information Technology (IT) departments to manage and secure their wireless networks. In recent years, researchers have uncovered security vulnerability- ties in Wi-Fi networks [20]. They showed that the Wired Equiv- agency Protocol (WEP), the popular 802.11 security mechanism that most corporations were using at the time, was fundamentally flawed. In a series of highly publicized papers, they showed that 802.11 networks could be compromised easily. The community reacted quickly by developing and deploying alternate security so- lotions including VPNs, IEEE 802.1x [30], several variations of EAP [14], Smart cards, and more recently WPA [29]. Yet, the wire- less LAN (WLAN) security problem was not completely resolved. Last year, Microsoft conducted a series of interviews with WLAN administrators of several large and small organizations [10]. The goal of these interviews was to understand the difficulties involved in deploying and managing corporate WLANs. The issue of WLAN security came up repeatedly during these interviews. All administrators felt that WLAN security was a problem. They were unhappy with the quality of the tools they had at their disposal. Many of them would periodically walk around their buildings using WLAN scanning software looking for security vulnerabilities. Some hired expensive outside consultants to conduct security vulnerability analyses of their WLAN deployme nt, only to conclude that what they really needed was an on-going monitoring and alerting system. Most administrators believed that better systems to manage WLAN security are needed. Even after protocols such as IEEE 802.1x and WPA are deployed, corporate networks can be compromised by off-the-shelf 802.11 hardware and software. For example, an unauthorized AP can be connected to the corporate Ethernet, allowing unauthorized clients to connect to the corporate network. The rogue AP may be con- nected by a malicious person or, as is more often the case, by an employee who innocently connects an AP in his office without realizing that he is compromising the corporate network. A rogue AP can circumvent the elaborate security measures that the IT department may have put in place to protect the companys intellectual property. To test our assertion that people inadvertently compromise the security of their networks, we conducted an experiment in two large organizations that had secured their WLANs using one of the methods mentioned previously. We walked around with a WLAN- enabled laptop in a small section of the two campuses looking for APs to which we could connect. Chapter 2 SECURITY ATTACKS Here I attempts to provide a comprehensive overview of attacks and secure routing. It first analyzes the reason that ad hoc network is vulnerable to attacks. Then it presents the well known attacks and the popular secure protocols. Is out of its radio range, the cooperation of other nodes in the Network is needed. This is known as multi-hop communication. Therefore, each node must do something as both a host and a router at the same time. In most wireless networking environments in productive use today the users devices communicate either via some networking infrastructure in the form of base stations and a backbonenetwork,ordirectlywiththeirintended communication partner, e.g. by means of 802.11 in ad hoc networks In distinction a mobile ad-hoc network is a self-configuring network that is formed automatically via wireless links by a collection of mobile nodes without the help of a fixed infrastructure or centralized management. Every hop in the mobile ad-hoc networks is ready with a wireless transmitter and receiver, which allow it to communicate with other nodes in its radio communication area. Hops are more often share the same physical media. They broadcast and obtain signals at the same frequency band, and chase the same hopping series or spreading code. If the purpose node is not inside the broadcasting range of the sending node, then the sending node takes help of the intermediate hops to communicate with the purpose node by relaying the messages hop by hop. Fig.2 describes the Mobile ad-hoc network. In order for a node to forward a packet to a node that TYPES OF THE SECURITY ATTACKS Securing wireless ad hoc networks is a highly demanding issue. Due to dynamic scattered infrastructure-less nature and be deficient in of centralized monitoring points, the ad hoc networks are susceptible to a variety of attacks. Ad hoc networks have to manage with the same kinds of vulnerabilities as their wired counterparts. As well as with new vulnerabilities specific to the ad hoc context. In addition, conventional vulnerabilities are also accentuated by the ad hoc paradigm. Initially, the wireless channel is available for the both genuine network users and cruel attackers. The ad hoc networks are vulnerable to attacks ranging from static eavesdropping to active prying. Secondly, the be short of an online CA or Trusted Third Party adds the complexity to organize security mechanisms. Thirdly, mobile devices be inclined to have limited power consumption and calculation capabilities which make it more vulnerable to Denial of Service attacks and incapable to execute computation-heavy algorithms like public key algorithms Fourthly, in MANETs, therearemore probabilities for trusted node being compromised and then life form used by adversary to launch attacks on networks. Lastly, node mobility and recurrent topology changes enforce frequent networking reconfiguration which creates more chances for attacks, for example, it is difficult to discriminate between stale routing information and faked routing information. Ad -hoc networks attacks can be differentiated as passive and active. Passive attack signifies that the assailant does not send any message, but just listens to the channel. Passive attacks do not disturb the process of a protocol, but only makes the attempts to find out valuable information. Active attacks may either being directed to disturb the normal operation of a exact node or target the performance of the ad hoc network as a whole. For passive attacks, the attacker listens to the channel and packets that are containing clandestine information might be eavesdropped, which violates privacy. In a wireless environment it is usually not possible to notice this attack, as it does not create any new traffic in the network. Active attacks, counting injecting packets to unacceptable destinations into the network, deleting packets, changing the contents of packets, and impersonating other hops infringe ease of use, veracity, verification, and non-repudiation. Different from the passive attacks, active attacks can be detected and ultimately avoided by the legal nodes that contribute in an ad hoc network . We broadly classify these attacks as passive and active. The classification is important for understanding the strengths and limitations of the DAIR security management system. Eavesdropping Eavesdropping is a passive attack. The attacker passively listens to the traffic on the wireless network and gleans useful information. The listener may use sophisticated code breaking techniques. Countermeasures include use of better encryption techniques as well as physical security measures such as use of radio-opaque wallpaper. Passive attacks are difficult, if not impossible, to detect and we do not address them in this paper. Intrusion Any attack that allows a user to gain unauthorized access to the network is called an Intrusion attack. Intrusion attacks are active attacks and several such attacks are possible. An attacker can compromise the corporate network by gaining physical access to its wired network and connecting a wireless AP to it. The AP creates a â€Å"hole† through which unauthorized clients can connect, bypassing the elaborate security measures that the IT department may have put in place. A similar attack can be carried out by using ad-hoc wireless networks instead of APs. A corporate network may also be compromised when an attacker finds and uses an unsecured AP connected to the network by an unsuspecting employee. The widespread availability of inexpensive, easy-to- deploy APs and wireless routers has exacerbated this problem. As mentioned earlier, we found several unsecured APs in large organizations. The DAIR security management system can detect both rogue APs and rogue ad-hoc networks. Another way a corporate network can be compromised is when an attacker obtains the credentials (e.g., WEP passwords, IEEE 802.1x certificates) needed to connect to the corporate ne twork. The DAIR security management system can not currently detect such attacks. Denial of Service (DoS) Denial of Service attacks are active attacks. A diversity of DoS attacks are possible. Some DoS attacks exploit flaws in the IEEE 802.11 protocol. For example, a disassociation attack is where the attacker sends a series of fake disassociation or deauthentication messages, causing legitimate clients to disconnect from the AP. In a NAV attack, the attacker generates packets with large duration values in the frame header, thereby forcing legiti- mate clients to wait for long periods of time before accessing the network . In a DIFS attack, the attacker exploits certain timing- related features in the IEEE 802.11 protocol to aggressively steal bandwidth from legitimate users. In all three cases, the attacker transmits packets in an abnormal way, either by generating non-compliant packets, or by transmitting compliant packets at an abnormally high rate. The DAIR security management system can detect such attacks. DoS attacks are also possible by creating large amount of RF noise in the ne ighborhood of the network. The DAIR security management system can detect such attacks by comparing current observations with historical data observed from multiple vantage points. DoS attacks can also be mounted by gaining access to the corporate wired network and attacking the APs from the wired side. The DAIR system does not handle DoS attacks on the wired network. Phishing Phishing is an active attack. An attacker sets up a wireless AP that masquerades as a legitimate corporate AP (same SSID, per- haps even same BSSIDs). If the client does not use mutual authentication, it is possible for the attacker to lure unsuspecting legiti- mate users to connect to its AP. The attacker can then use a variety of techniques to extract private information (for example, sniff for passwords). The DAIR system can detect phishing attacks. How- ever, we do not describe solutions to phishing attacks in this paper. ACTIVE ATTACKS SECURITY ATTACKS Certain active attacks can be easily performed alongside an ad -hoc network. Understanding possible shape of attacks is for all time the first step towards increasing good safety solutions. Based on this danger analysis and the recognized capabilities of the potential attackers, several well recognized attacks that can target the operation of a routing protocol in an ad hoc network are discussed. Impersonation. In this kind of attack, nodes may be clever to join the network untraceable or can able to send the false routing data/information, camouflaged as some other trusted node. Wormhole. The wormhole attack involves the collaboration stuck between two attackers. One attacker gets the routing traffic at one point of the network and changes their path to another point in the network that shares a confidential communication link between the attackers, then selectively injects tunnel traffic back into the network. The two colluding assailant can potentially deform the topology and set up routes under the control over the wormhole link. Rushing attacks: The ROUTE REQUESTs for this Discovery sanded forwarded by the attacker can be the 1st to approach each neighbor of the target, then any way exposed by this Route Discovery will comprise a hop through the attacker. That is, when a neighbor of the target gets the hurried REQUEST from the attacker, and it forwards that REQUEST, and will not send onward any further REQUESTs from this Route Discovery. When non-attacking REQUESTs arrive later at these nodes, they will discard those legitimate REQUESTs. Blackmail: The attack incurs outstanding to be short of of genuineness and it grants stipulation for any node to corrupt other nodes legal information. Hops more often keep the data/ information of apparent malevolent nodes in a blacklist. This attack is pertinent alongside routing protocols that use mechanisms for the recognition of malicious nodes and spread messages that try to blacklist the criminal. An attacker may make such coverage messages and tell other nodes in the network to put in that hop to their blacklists and cut off legitimate nodes from the network. Chapter 3 Secure Routing The previously presented ad hoc routing protocols with no security contemplation assume that all participating nodes do not maliciously troublemaking the operation of the protocol. However, the continuation of malicious entities cannot be unnoticed in any system, particularly in open ones like ad hoc networks. Safe routing protocols manage with malicious nodes that can disturb the right performance of a routing protocol by changing routing information. By fabricating the wrong routing data or information and by impersonating other nodes. These safe routing protocols for ad hoc networks are either totally new stand-alone protocols, or in some cases incorporations of security mechanisms into obtainable protocols. Generally the obtainable safe routing protocols that have been future can be generally secret into two types, those that use hash chains, and those that in order to function require predefined trust relations. This method, jointly nodes can efficiently validate the legitimate traffic and distinguish the unauthenticated packets from outsider attackers. ROUTING PROTOCOL FOR AD-HOC NETWORK SECURITY SEAD: Safe Efficient Ad hoc Distance-vector routing protocol. A safe ad hoc network routing protocol that is established on the design of the Destination Sequenced Distance Vector routing protocol. To hold up employ of SEAD with hops of partial CPU processing abilities, and to guard against modification of the source address for a routing update and attacks in which an rejection of service attacks makes attempts to reason other nodes to use surplus network bandwidth or processing time of the network, efficient one way hash Chains but not cryptographic operations are used in the verification of the series number and the metric field of a routing table update message. When a node in SEAD sends a routing update, the node includes one hash value from the hash chain with each entry in that update. The nodes sets the purpose address in that entry to that target nodes address, the metric and series number to the values for that target in its routing table, and the hash value to the hash of the hash value conventional in the routing update entry from which it learned that route to that destination. When a node receives a routing inform, for each entry in that update, the node checks the verification on that entry, by the target address, sequence number, and metric in the conventional entry, together with the newest prior genuine hash value established by this node from that destinations hash chain. The hash value of each entry is hashed the right number of times and it is compared to the before authenticated v alue. Depending on this contrast the routing update is either established as authenticated, or discarded. Ariadne; Ariadne is a safe on-demand ad hoc routing protocol based on DSR that restricts attackers or the mutual hops from tampering with uncompromised routes containing of uncompromised hops, and also stops a lot of types of DOS attacks. In addition, Ariadne uses only extremely well-organized symmetric cryptographic primitives. To induce the objective of the authority of each field in a ROUTE REQUEST, the originator simply includes in the REQUEST a MAC computed with key over exclusive data. The object can with no trouble corroborate the authenticity and newness of the ROUTE REQUEST using the shared key. One-way hash functions are use to confirm that no hop was absent which is called per hop hashing. Three alternative methods to attain hop list verification. The TESLA protocol, digital signatures, and typical MACs. When Ariadne Route detection is used with TESLA, every node authenticates the original data in the REQUEST. The objective buffers and does not fire the REPLY awaiting midd le nodes can discharge the matching TESLA keys. Ariadne Route Discovery using MAC is the majority well-organized way of the three option verification mechanisms, but it asks couple wise communal keys among all nodes. The MAC list in the ROUTE REQUEST is computed by a key common among the object and the present node. The MACs are verified at the target and are not returned in the ROUTE REPLY. If Ariadne way detection is used with digital signatures, the MAC list in the ROUTE REQUEST becomes a signature list. SRP: The safe Routing Protocol consists of quite a lot of safety extensions that can be practical to existing ad hoc routing protocols as long as end-to-end verification. The one and only requirement of the future scheme is the sustained existence of a security association between the node initiating the query and the sought destination. The safety association is used to found a common secret between the two nodes, and the non mutable types of the exchanged routing messages are confined by this shared secret. The method is robust in the occurrence of a number of non-colluding nodes, and provides Routing Table Overflow: In a routing table spread out attack the malevolent node floods the network with bogus route formation packets to non existing nodes to overpower the routing protocol implementations in order to devour the resources of the participating nodes and interrupt the establishment of legal routes. The goal is to create enough routes to prevent new routes from being created or to engulf the protocol execution. Proactive routing protocols are more vulnerable to this attack, since they attempt to produce and preserve routes to all possible destinations. A spiteful node to apply this attack can simply send unnecessary route advertisements to the network. To apply this harasses in order to target a reactive protocol like AODV is to some extent more involved since two nodes are obligatory. The first node should make a genuine request for a route and the malicious node should reply with a forged address. Sleep Depravation: The sleep scarcity afflict aims at the utilization of store of a specific node by constantly keeping it busy in routing decisions. This attack floods the network with routing traffic in order to munch through battery life from the nodes and accessible bandwidth from the ad hoc network. The malicious node continually requirements for either existing or non-existing destinations forces the neighboring nodes to procedure and forward these packets and therefore munch through batteries and network bandwidth hindering the normal operation of the network. Location disclosure: Location disclosure is an attack that targets the solitude necessities of an ad hoc network. Through the use of traffic analysis techniques or with simpler probing and monitoring methods an attacker is able to discover the location of a node, and the structure of the network. If the locations of some of the intermediary nodes are known, one can gain information about the location of the destination node as well. Routing table poisoning: Routing protocols uphold tables which hold information on the subject of routes of the network. In poisoning attacks the malevolent nodes create and send untrue traffic, or modify legitimate messages from other nodes, in order to create false entries in the tables of the participating nodes. One more option is injecting a RREQ package with a high sequence number. This will reason that all other legal RREQ packets with lower sequence number will be deleted. Routing table poisoning attacks can result in selection of non-optimal routes, creation of routing loops, bottlenecks and even partitioning sure parts of the network. Black Hole: A malicious node uses the routing protocol to insert fake route answers to the route needs it receives promotion itself as having the straight path to a target whose packets it needs to cut off. Once the fake route has been recognized the mean node is able to become a member of the lively route and intercept the communication packets. Network traffic is diverted through the malicious node for eavesdropping, or be a focus for all traffic to it in order to execute a DOS by dropping the received packets or the first step to a man-in-the-middle attack. While the safety requirements for ad hoc networks are the similar the ones for fixed networks, namely ease of use, privacy, reliability, validation, and non-repudiation mobile wireless networks are usually more susceptible to information and physical safety fears than fixed wired networks. Securing wireless ad hoc networks is chiefly tricky for many reasons as well as vulnerability of channels and nodes, nonattendance of communications, dynamically altering topology and etc.; The wireless channel is available to both legal network users and malicious attackers. The abstract of centralized management makes the traditional security solutions based on certification establishment and on-line servers unsuitable. A malicious attacker can willingly become a router and disturb network operations by deliberately disobeying the protocol specifications. The nodes can move arbitrarily and liberally in any way and systematize themselves arbitrarily. They can stick together or leave the network at any time. The network topology changes regularly, rapidly and randomly which considerably alters the status of trust among nodes and adds the complexity to routing among the mobile nodes. The egoism that nodes in ad hoc networks may tend to reject providing services for the advantage of other nodes in order to keep their own possessions introduces new security issues that are not address in the infrastructure-based network Chapter No 3 Distributed Security Scheme for Mobile Ad Hoc Networks In difference to fixed networks a central certification power is not possible in ad hoc networks. Distributing the functionality of certification power over number of nodes is a probable solution. This can be got by creating n shares for a clandestine key and distributing them to n different node. Key can be generating by combining the shares using doorsill cryptography methods. Mobile ad-hoc networks are extremely active. Topology differences and link crack occur fairly often. Therefore, we require a safety answer which is active, too. Any malicious or disobedient nodes can produce antagonistic attacks. These types of attacks can gravely injure essential aspects of safety, such as veracity, confidentiality and space to yourself of the node. Current ad-hoc routing protocols are totally unsure of yourself. Furthermore, obtainable safe routing mechanisms are either too luxurious or have impractical necessities. In ad hoc network, safety solution should separate the attackers and compro mised nodes in the network. Proactively dividing the attackers make it sure that they cannot carry on to attack and waste the network resources in future. A safety solution should have lessening transparency over. Attacks beside ad-hoc routing protocols can be categorize as active or passive. A passive attack does not upset the functioning of the protocol, but tries to discover valuable information by listening to traffic. An active attack inserts arbitrary packets and tries to upset the operation of the protocol in order to bound the accessibility, gain confirmation, or attract packets meant to other nodes. In ad hoc network disobedient node can advertise its accessibility. Nearby nodes changs its route table with the new route and ahead the packet through the disobedient node. Misbehaving node can alter or even drop the packet. So mobile nodes must be able to prove the reliability of a new neighbor before adding it to the route table. Also it is imperative to care for the data pac kets from eavesdropping. Once the cluster member link has reputable a secured link, they can further switch symmetric key and encrypt data packet to ensure data in private and integrity. CLUSTER-BASED TOPOLOGY Clustering is a method by which nodes are placed into groups, called clusters. A cluster head is designated for

Essay on Pride and Prejudice as Romantic Novel and Romantic Criticism

Pride and Prejudice as Romantic Novel and Romantic Criticism       To a great extent, Jane Austen satirizes conventional romantic novels by inverting the expectations of "love at first sight" and the celebration of passion and physical attractiveness, and criticizing their want of sense. However, there are also elements of conventional romance in the novel, notably, in the success of Jane and Bingley's love.    The first indication of Austen's inversion of accepted romantic conventions is Elizabeth and Darcy's mutual dislike on first sight. However, Jane and Bingley fall in love almost immediately, and the development of their romance follows conventional romantic-novel wisdom, down to the obstacles in the form of Darcy's and Bingley's sisters' disapprobation (the typical disapproval of the Family) and the attraction between the rich young man and the middle class maid. Their Cinderella story ends in happily-ever-after, as does Elizabeth's and Darcy's. Elizabeth's defiance of Lady Catherine recalls Meg's defiance of her aunt in Little Women, and Darcy's willingness to accept Elizabeth despite the inferiority of her connections is a triumph of conventional romantic-novel expectations.    One of the most striking examples of Austen's satire is her emphasis on reason, as opposed to the wanton passion lauded into the bulk of romantic novels. Lydia and Wickham's marriage is seen as a triumph of their "passions" over their "virtue", and she is certain that "little permanent happiness" can arise from such a union. This is exemplified by Wickham's continuance of his extravagant habits, and the degeneracy of any feelings between them to indifference. The indifference Mr Bennet has for his wife, and the unsatisfactorine... ...Holmes & Meier Publishers, Inc., 1983. Jane Austen Info Page. Henry Churchyard. U of Texas, Austin. 23 Nov. 2000.   Ã‚  Ã‚  Ã‚   <http://www.pemberly.com/janeinfo/janeinfo/html>. Kaplan, Deborah.   Structures of Status: Eighteenth-Century Social Experience as Form in Courtesy Books and Jane Austen's Novels. Diss. University of Michigan, 1979. Monaghan, David.   Jane Austen Structure and Social Vision.   New York: Barnes & Noble Books, 1980. Poplawski, Paul.   A Jane Austen Encyclopedia.   Westport, Connecticut: Greenwood Press, 1998. Reidhead, Julia, ed. Norton Anthology of English Literature vol. 7, 2nd ed. New York: W.W. Norton & Company, 2000. Ward, David Allen. "Pride and Prejudice." Explicator. 51.1: (1992). Wright, Andrew H. "Feeling and Complexity in Pride and Prejudice." Ed. Donald Gray. New York: W.W. Norton & Company, 1966. 410-420.

Zoe’s Tale PART I Chapter Eight

â€Å"You seem sad,† Hickory said, as we took the shuttle back to Phoenix Station. Dickory sat next to Hickory, impassive as ever. â€Å"I am sad,† I said. â€Å"I miss my mother and father.† I glanced over to John, who was sitting in the front of the shuttle with the pilot, Lieutenant Cloud. â€Å"And I think all this moving and leaving and going is getting to me a little bit. Sorry.† â€Å"No need to apologize,† Hickory said. â€Å"This journey has been stressful for us, too.† â€Å"Oh, good,† I said, turning back to the two of them. â€Å"Misery loves company.† â€Å"If you would like we would be happy to try to cheer you up,† Hickory said. â€Å"Really,† I said. This was a new tactic. â€Å"How would you do that?† â€Å"We could tell you a story,† Hickory said. â€Å"What story?† I asked. â€Å"One that Dickory and I have been working on,† Hickory said. â€Å"You've been writing?† I said. I didn't bother to keep the incredulousness out of my voice. â€Å"Is it that surprising?† Hickory said. â€Å"Absolutely,† I said. â€Å"I didn't know you had it in you.† â€Å"The Obin don't have stories of their own,† Hickory said. â€Å"We learned about them through you, when you had us read to you.† I was puzzled for a minute, and then I remembered: When I was younger I asked Hickory and Dickory to read bedtime stories to me. It was a failed experiment, to say the least; even with their consciousness machines on, neither of them could tell a story to save their lives. The beats were all wrong – they didn't know how to read the emotions in the story is the best way I can put it. They could read the words, all right. They just couldn't tell the story. â€Å"So you've been reading stories since then,† I said. â€Å"Sometimes,† Hickory said. â€Å"Fairy tales and myths. We are most interested in myths, because they are stories of gods and creation. Dickory and I have decided to make a creation myth for the Obin, so we have a story of our own.† â€Å"And this is the story you want to tell me,† I said. â€Å"If you think it would cheer you up,† Hickory said. â€Å"Well, is it a happy creation myth?† I asked. â€Å"It is for us,† Hickory said. â€Å"You should know you play a part in it.† â€Å"Well, then,† I said. â€Å"I definitely want to hear it now.† Hickory conferred with Dickory quickly, in their own language. â€Å"We will tell you the short version,† Hickory said. â€Å"There's a long version?† I said. â€Å"I'm really intrigued.† â€Å"The remainder of the shuttle ride will not be long enough for the long version,† Hickory said. â€Å"Unless we then went back down to Phoenix. And then back up. And then back down again.† â€Å"The short version it is,† I said. â€Å"Very well,† Hickory said, and began. â€Å"Once upon a time – â€Å" â€Å"Really?† I said. â€Å"‘Once upon a time'?† â€Å"What is wrong with ‘once upon a time'?† Hickory asked. â€Å"Many of your stories and myths start that way. We thought it would be appropriate.† â€Å"There's nothing wrong with it,† I said. â€Å"It's just a little old-fashioned.† â€Å"We will change it if you like,† Hickory said. â€Å"No,† I said. â€Å"I'm sorry, Hickory, I interrupted you. Please start again.† â€Å"Very well,† Hickory said. â€Å"Once upon a time†¦Ã¢â‚¬  Once upon a time there were creatures who lived on a moon of a large gas planet. And these creatures did not have a name, nor did they know they lived on a moon, nor did they know that moon circled a gas planet, nor what a planet was, nor did they know anything in a way that could be said that they were knowing it. They were animals, and they had no consciousness, and they were born and lived and died, all their lives without thought or the knowledge of thought. One day, although the animals knew nothing of the idea of days, visitors came to the moon that circled the gas planet. And these visitors were known as Consu, although the animals on the planet did not know that, because it was what the Consu called themselves, and the animals were not smart and could not ask the Consu what they called themselves, or know that things could have names. The Consu came to the moon to explore and they did, noting all the things about the moon, from the air in its sky to the shape of its lands and waters to the shape and manner of all the life that lived in the moon's land, air and water. And when they came to these certain creatures who lived on this moon, the Consu became curious about them and how they lived their lives, and studied them and how they were born and lived and died. After the Consu had watched the creatures for some time the Consu decided that they would change the creatures, and would give them something that the Consu possessed and that the creatures did not, which was intelligence. And the Consu took the genes of the creatures and changed them so that their brains, as they grew, would develop intelligence well beyond what the creatures would themselves achieve through experience or through many years of evolution. The Consu made these changes to a few creatures and then set them back on the moon and over many generations all the creatures became intelligent. Once the Consu gave intelligence to the creatures they did not stay on the moon, nor shared themselves with the creatures, but departed and left machines above the sky, which the creatures would not see, to watch the creatures. And so the creatures for a very long time did not learn of the Consu and what they had done to the creatures. And for a very long time these creatures who now had intelligence grew in number and learned many things. They learned how to make tools and create a language and work together for common goals and to farm the land and mine metals and create science. But although the creatures thrived and learned, they did not know that they among all intelligent creatures were unique, because they did not know there were other intelligent creatures. One day, after the creatures had gained intelligence, another race of intelligent people came to visit the moon, the first since the Consu, although the creatures did not remember the Consu. And these new people called themselves the Arza and each of the Arza also had a name. And the Arza were amazed that the creatures on the moon, who were intelligent and who had built tools and cities, did not have a name and did not have names for each of their number. And it was then the creatures discovered through the Arza what made them unique: They were the only people in all the universe who were not conscious. Although every creature could think and reason, it could not know itself as every other intelligent creature could know itself. The creatures lacked awareness of who they were as individuals, even as they lived and thrived and grew on the face of the moon of the planet. When the creatures learned this, and although no individual could know it felt this, there grew within the race of these creatures a hunger for that thing they did not have: for the consciousness that the creatures knew collectively they did not have as individuals. And this is when the creatures first gave themselves a name, and called themselves â€Å"Obin,† which in their language meant â€Å"The ones who lack,† although it might be better translated as â€Å"The deprived ones† or â€Å"The ones without gifts,† and although they named their race they did not give names to each of their individual number. And the Arza took pity on the creatures who now called themselves Obin, and revealed to them the machines that floated in the sky and that were put there by the Consu, who they knew to be a race of immense intelligence and unknowable aims. The Arza studied the Obin and discovered that their biology was unnatural, and so the Obin learned who had created them. And the Obin asked the Arza to take them to the Consu, so they could ask why the Consu had done these things, but the Arza refused, saying the Consu met only with other races to fight them, and they feared what would happen to the Arza if they brought the Obin before the Consu. So it was the Obin determined they must learn to fight. And while the Obin did not fight the Arza, who had been kind to the Obin and took pity on them and then left the Obin in peace, there came another race of creatures called the Belestier, who planned to colonize the moon on which the Obin lived and kill all the Obin because they would not live in peace with them. The Obin struggled with the Belestier, killing all those who landed on their moon, and in doing so found they had an advantage; because the Obin did not know themselves, they were not afraid of death, and had no fear where others had fear in abundance. The Obin killed the Belestier, and learned from their weapons and technology. In time the Obin left their own moon to colonize other moons and grow their numbers and make war on other races when those other races chose to make war on the Obin. And there came a day, after many years, when the Obin decided they were ready to meet the Consu, and found where they lived and set out to meet them. Although the Obin were strong and determined, they did not know the power of the Consu, who brushed them aside, killing any Obin who dared to call or attack, and there were many thousands of these. Eventually the Consu became curious about the creatures they had made and offered to answer three questions for the Obin, if half the Obin everywhere would offer themselves up as a sacrifice to the Consu. And this was a hard bargain, because although no individual Obin would know its own death, such a sacrifice would wound the race, because by this time it had made many enemies among the intelligent races, and they would most certainly attack the Obin when they were weak. But the Obin had a hunger and needed answers. So one half of the Obin willingly offered themselves to the Consu, killing themselves in all manner of ways, wherever they were. And the Consu were satisfied and answered our three questions. Yes, they had given the Obin intelligence. Yes, they could have given the Obin consciousness but did not, because they wanted to see what consciousless intelligence was like. No, they would not now give us consciousness, nor would they ever, nor would they allow us to ask again. And since that day the Consu have not allowed the Obin to speak to them again; each embassy to them since that day has been killed. The Obin spent many years fighting many races as it returned itself to its former strength, and in time it became known to other races that to fight with the Obin meant death, for the Obin would not relent or show mercy or pity or fear, because the Obin did not know these things themselves. And for a long time this was the way of things. One day a race known as the Rraey attacked a human colony and its space station, killing all the humans they could. But before the Rraey could complete their task, the Obin attacked them, because the Obin wanted the colony world for themselves. The Rraey were weakened after their first attack and were defeated and killed. The Obin took the colony and its space station, and because the space station was known as a scientific outpost, the Obin looked through its records to see what useful technology they could take. It was then that the Obin discovered that one of the human scientists, who was named Charles Boutin, was working on a way to hold and store consciousness outside of the human body, in a machine based on technology the humans had stolen from the Consu. The work was not done, and the technology was not something the Obin at the space station could follow, nor the Obin scientists whom they had brought along. The Obin looked for Charles Boutin among the human survivors of the space station attacks, but he was not to be found, and it was discovered that he was away from the station when it was attacked. But then the Obin learned that Charles Boutin's daughter Zoe had been on the space station. The Obin took her from the station and she alone was spared among the humans. And the Obin kept her and kept her safe and found a way to tell Charles Boutin that she was alive and offered to return her if he would give the Obin consciousness. But Charles Boutin was angry, not at the Obin but at the humans who he thought had let his daughter die, and demanded in exchange for giving the Obin consciousness, that the Obin would make war on the humans, and defeat them. The Obin could not do this themselves but allied with two other races, the Rraey, whom they had just attacked, and the Enesha, who were allies of the humans, to make war on the humans. Charles Boutin was satisfied and in time joined the Obin and his daughter, and worked to create consciousness for the Obin. Before he could finish his task, the humans learned of the alliance between the Obin and the Rraey and the Enesha, and attacked. The alliance was broken and the Enesha were made to war on the Rraey by the humans. And Charles Boutin was killed and his daughter Zoe was taken from the Obin by the humans. And although no individual Obin could sense it, the entire nation despaired because in agreeing to give them consciousness Charles Boutin was their friend among all friends, who would do for them what even the great Consu would not: give them awareness of themselves. When he died, their hope for themselves died. To lose his daughter, who was of him and who was dear to them because of him, compounded this despair. And then the humans sent a message to the Obin that they knew of Boutin's work and offered to continue it, in exchange for an alliance and the agreement by the Obin to war on the Enesha, who had allied with the Obin against the humans, once the Enesha had defeated the Rraey. The Obin agreed to this but added the condition that once the Obin were given consciousness that two of their number would be allowed to know Zoe Boutin, and to share that knowledge with all other Obin, because she was what remained of Charles Boutin, their friend and their hero. And so it was that the Obin and the humans became allies, the Obin attacked and defeated the Enesha in due time, and the Obin, thousands of generations after their creation, were given consciousness by Charles Boutin. And among their number, the Obin selected two, who would become companions and protectors to Zoe Boutin and share her life with her new family. And when Zoe met them she was not afraid because she had lived with the Obin before, and she gave the two of them names: Hickory and Dickory. And the two of them became the first Obin to have names. And they were glad, and they know they are glad, because of the gift Charles Boutin gave them and all Obin. And they lived happily ever after. Hickory said something to me I didn't hear. â€Å"What?† I said. â€Å"We are not sure ‘and they lived happily ever after' is the appropriate ending,† said Hickory, and then stopped and looked closely at me. â€Å"You are crying,† it said. â€Å"I'm sorry,† I said. â€Å"I was remembering. The parts of it I was in.† â€Å"We told them wrong,† Hickory said. â€Å"No,† I said, and put up my hand to reassure it. â€Å"You didn't tell it wrong, Hickory. It's just the way you tell it and the way I remember it are a little†¦Ã¢â‚¬  I wiped a tear off my face and searched for the right word. â€Å"They're just a little different, is all.† â€Å"You do not like the myth,† Hickory said. â€Å"I like it,† I said. â€Å"I like it very much. It's just some things hurt me to remember. It happens that way for us sometimes.† â€Å"I am sorry, Zoe, for causing you distress,† Hickory said, and I could hear the sadness in its voice. â€Å"We wanted to cheer you up.† I got up from my seat and went over to Hickory and Dickory and hugged them both. â€Å"I know you did,† I said. â€Å"And I'm really glad you tried.†

Introduction Windows vs. Linux essays

Introduction Windows vs. Linux essays Windows and Linux come in various versions. Within the Windows family there are two main lines: Windows 9x which consists of Windows 95, 98, 98se and Me, and NT classes (Windows NT, 2000, and XP). The birth of Windows actually started out with Windows 3.0 which was a DOS overlay. The versions of Linux are referred to as distributions. The marketing of the products differ in that purchases of Microsoft are strictly controlled by Microsoft and licensing is purchased from Microsoft. With Linux there are different versions of the product that are written by different companies. Examples of this are Redhat, Lindows, and SUSE (our software of choice). All the Linux versions released around the same time frame will use the same kernel. They differ in the add-on software provided1. The differences between Linux distributions will be less obvious to the standard user and more obvious to a technical user. This is equivalent to the differences between Windows 95, 98, 98se and Me. Windows 2000 provides a wide range of benefits, features and functionality such as: Enhanced file management: Windows 2000 provides significant enhancements to file management, including: Disk defragmenting, which NT 4.0 lacks. Encrypted File System (EFS) uses public key technology to encrypt files or folders. Backup software: Ntbackup is extremely useful for backing up files that the operating system always has open, such as Active Directory databases and the registry. Distributed File System (Dfs) makes it easier for users to locate data on the network. Plug and Play implementation, similar to Windows 98, makes it easier to install devices. Group Policy allows administrators to manage the desktops of user running Windows 2000 Professional, including which applications they can use. Another service that Windows 2000 Server offers is Terminal Services. This service Allows client machines ...