Browsing by Author "Gupta, Vishal"

Now showing 1 - 20 of 26

Bit-Stuffing in 802.11 Beacon Frame: Embedding Non-Standard Custom Information
(International Journal of Computer Applications, 2013-02) Gupta, Vishal; Rohil, Mukesh Kumar
In an infrastructure Basic Service Set (BSS) beacon frames are transmitted periodically by the Access Point (AP) and announce the presence of a wireless network. It mainly consists of network specific information and thus one of its main purposes is the "advertisement" of this information. Based on this information mobile devices can take many decisions, for example, whether to attempt association with the network or not. To facilitate the communication between devices developed by different vendors, IEEE 802.11 standardizes the arrangement of this information in beacon frames. Often it is required to embed non-standard vendor/network specific additional information in the beacon frame. In this paper we show that without disturbing the arrangement of information as per the standard, how the IEEE 802.11-2012 compatible beacon frames can be overloaded with additional non-standard information. Moreover, the 802.11 standard limits the maximum size of the beacon frame. In this perspective we also show that how to send large amount of information in multiple successive beacon frames using the already implemented concept of fragmentation and sequence numbers. The proposed technique is flexible in terms of fields used for embedding the information and maximizes the number of additional non-standard information octets per beacon. The results of its implementation in ns-3 simulator are also shown.
Blended SPOC Teaching and Learning Model for Computer Programming Course: Insights and Defeating Challenges
(IEEE, 2020) Gupta, Vishal
To expose all budding engineers to the world of programming, generally, Computer Programming is a first-year compulsory course across all Engineering disciplines. While this course has been taught for a long in the university whose case study is presented here, the following challenges were faced over the past few years: (a) University expended itself from one campus to four geographically distant campuses. (b) Many (but not all) students now are already exposed to this programming subject at their respective 10+2 level, which poses a challenge to an instructor. (c) The focus of this course is on “Programming” and C-language is a tool to learn it, but often students feel the reverse. (e) Although all campuses shared a common handout that standardized the breadth coverage of this course, in-depth coverage could not be standardized. To overcome these problems, the university changed the teaching model of the course to a flipped classroom-based blended SPOC (Small Private Online Course) learning model. This paper shares the insights and experience of successive change in pedagogy over four years and relates it with intrinsic motivation vs. extrinsic motivation, standardizing in-depth coverage of any course across geographically distant campuses, and getting closer towards achieving the learning objectives.
Comparative Performance of Contradictory and Non-Contradictory Judgement Matrices in AHP Under Qualitative and Quantitative Metrics
(IGI Global, 2018) Gupta, Vishal
Over the years, although AHP has proved its success in various diverse fields, many authors in the literature have also shown its shortcomings, often called as criticisms of AHP. One such criticism is allowing the consideration of contradictory judgement matrices. Such matrices violate the principle of ordinal transitivity and thus there does not exist any ranking of corresponding decision elements which satisfy all the judgements. In this paper, the results of our investigation towards measuring this criticism are further explored and discussed by comparing the quality of priority vector of contradictory judgement matrices and non-contradictory judgement matrices under Rank Reversals and the common frame work of “aggregated deviation”. The results further strengthen the notion of contradictory judgement matrices as a strong criticism of AHP for higher order judgement matrices and necessitate some proper avoidance (if not elimination) procedure for them.
DDoS Prevention: Review and Issues
(Springer, 2021) Gupta, Vishal
Networks connected to the Internet are always susceptible to distributed denial-of-service (DDoS) attacks. In spite of a lot of different DDoS defense mechanisms in place, DDoS attacks still happen. These mechanisms fall under the category of DDoS detection, DDoS mitigation, and DDoS prevention. Although DDoS detection and mitigation are well defined and understood terms, DDoS prevention is used with different meanings in the literature. Concerning reflection-based DDoS amplification attacks, in this paper, we define ideal prevention and true prevention. Former is an ideal situation in which primarily the security of all the Internet hosts is well up to the mark and does not allow them to become participating members of DDoS attacks, whereas later is a practically feasible situation in which the network itself can prevent and mitigate DDoS attack within some fixed time interval. We also provide the literature review of DDoS prevention techniques and argue that the ones which conform to the definition of ideal prevention or true prevention are either not dynamic, are computationally expensive, or not scalable; thus, practically not feasible.
Detection of Distributed Denial of Service Attacks Using Entropy on Sliding Window with Dynamic Threshold
(Springer, 2022-03) Gupta, Vishal
The Internet has become an integral part of our day-to-day lives, from remaining connected to accessing information from any part of the world. Distributed Denial of service (DDoS) attacks disrupts the normal functioning of the Internet. Because of DDoS attacks, services over the Internet become inaccessible; regular hosts lose connectivity, etc. DDoS attacks are more dangerous because it is not always possible to differentiate whether an organization is under attack or its’ just normal traffic. Therefore, an effective detection mechanism is needed that is computationally less expensive and can detect different types of attacks with good accuracy. Hence, in this paper, we propose Entropy with Dynamic Thresholds to detect DDoS attacks. A dynamic threshold helps us accurately detect an attack in different rates of traffic. To validate our approach, we have used the CICDDoS-2019 attack dataset.
DNS Amplification Based DDoS Attacks in SDN Environment: Detection and Mitigation
(IEEE, 2019) Gupta, Vishal; Kulshrestha, Rakhee
Domain Name System (DNS) amplification based Distributed Denial of Service (DDoS) attacks have been part of the Internet's history for a long time. Since the inception of Internet protocol, several security measures, improved protocols, and hardware have been developed but there still is not a foolproof way to avoid such DDoS attacks. Attackers have used it to congest networks and servers with the aim of disrupting services which in turn lead to huge financial losses. Software-Defined Network (SDN) environment has evolved as a promising alternative to legacy networks. It essentially gives the underlying network an external controller (brain) which makes respective network layer devices centrally programmable. This gives administrators absolute control over the network, to decide and take action on how each and every packet in the network should move around. It is predicted as the future of computer networking to thwart major cyberattacks with nearly full autonomy on the network. Through this research, it is intended to identify and mitigate DNS Amplification based DDoS attacks in such an environment. A middle-layer third-party solution is proposed to protect an organization's network by offloading the attack to an open flow enabled SDN network. Using a bloom filter as a defense mechanism, detection and mitigation of an attack is done.
Enhancing Wi-Fi with IEEE 802.11u for Mobile Data Offloading
(International Journal of Mobile Network Communications & Telematics, 2012-08) Rohil, Mukesh Kumar; Gupta, Vishal
Apart from voice services, data made its foray in cellular networks with 2.5G networks. Today, with 3G network already in place, the data requirements of mobile subscribers is very high. With the increasing demand for mobile internet and rich data services such as streaming media for audio and video, this data requirement is expected to multifold in near future. Correspondingly the network operators have started looking for alternative means of satisfying these data needs. Among many alternatives, mobile data offloading (MDO) is the most promising one. This paper presents the extensive need, benefits, and technological solutions for MDO. Qualitatively, it is also shown that Wi-Fi, or 802.11 network is the most promising technology for MDO. Also, to further popularize Wi-Fi as a candidate network for MDO, IEEE published the enhancements to the base IEEE 802.11-2007 standard in the form of its ninth amendment (i.e. IEEE 802.11u). Restricting the scope to beacon frame only, we show how this amendment supports interworking of 802.11 network with external networks. We also show the benefit of 802.11u compatible Wi-Fi, as a candidate network for MDO, by modelling the problem of taking user's choice for assisting any vertical handover decision algorithm.
An experimental measurement of contradictory judgement matrices in AHP
(IEEE, 2012) Rohil, Mukesh Kumar; Gupta, Vishal
Often Multi Criteria Decision Making (MCDM) techniques are used to assist in deciding a best choice, or alternative, in many different types of environment. Analytic Hierarchy Process (AHP) is one of the most popular MCDM technique used in variety of domains. It not only generates numerical order of alternatives that indicates an order of preference among them but also reflect there intensity or cardinal preference among them. Despite its advantages and popularity, AHP is often criticized in the literature for many reasons. One such reason is the Consistency Index which it requires to compute for every judgement matrix. As a result of this, it allows the consideration of Contradictory matrices for which no true ordinal ranking satisfying all the relations contained in the judgement matrix can exist. This paper shows the results of an experimental analysis as an attempt to measure the magnitude of this problem. Results show that as the order of pair wise comparison matricx increases the intensity of this problem also increases.
Handover procedure using probability based mobility patterns in 3G-WLAN interworking environment
(IEEE, 2012) Gupta, Vishal
With the projected increase of 3G network traffic in near future, telecom operators are looking for the alternative means of satisfying the data needs of mobile subscribers without scaling the existing 3G network infrastructure. Over the last decade, IEEE 802.11 network (better called as Wi-Fi network) has emerged as one of the most competitive technology for it. It can function with the macro cellular network, as an adjunct network, to provide an alternative path with the best performance capability. On the other hand, several studies have reported the discovery of fundamental statistical features of human mobility. Studies show that human trajectories show a high degree of temporal and spatial regularity, thus following simple reproducible patterns. This paper proposes a probability based approach to find the mobility patterns of users and then use the information to effectively decrease the handover latency and increase throughput.
Improved Beacon-Stuffing and Quantification of Criticisms in Analytic Hierarchy Process for Infrastructure WLANs
(BITS Pilani, 2013) Gupta, Vishal
Information Embedding in IEEE 802.11 Beacon Frame
(International Journal of Computer Applications, 2012) Rohil, Mukesh Kumar; Gupta, Vishal
According to IEEE 802.11 protocol, beacon frames are periodically transmitted by the Access Point (AP) and carry mostly network specific information. All the wireless stations (or wireless clients) with in the "vicinity" of transmission range of AP receive corresponding beacon and use the information embedded in it for various purposes. The arrangement of information in beacon is standardized by 802.11, thus facilitating communication between different devices manufactured by different vendors. Also, the IEEE 802.11-2007 is the base protocol and its several amendments have been published by IEEE till date. In this paper we show that with out breaching the standard, where additional non-standard information can be embedded on the transmitted fields of 802.11 beacon frame. This facilitates the non-standard, vendor/network specific communication of information from AP to wireless clients without Association.
KarmaNet: SDN Solution to DNS-Based Denial-of-Service
(Springer, 2019-01) Gupta, Vishal
Networks are fundamentally designed to efficiently share network resources among end-users. The Internet has facilitated a global communication and computational environment by interconnecting billions of computers. People depend on the Internet to share professional, personal, confidential, and valuable information with other network users. Because of this high dependency of users, attackers often exploit its weaknesses to paralyze crucial and important segments of the Internet. Domain Name System (DNS) is one such segment whose proper functioning is highly crucial for the Internet to function properly. Attackers often exploit vulnerabilities of the Internet and DNS to launch large scale Distributed Denial of Service (DDoS) attacks and disrupt network services. Such DNS based DDoS attacks generally use IP spoofing to bombard target network/host so as to paralyze them with attack packets. In this paper we present a novel DDoS attack prevention mechanism by utilizing the flexibility and programmability aspects of Software Defined Networks (SDN). The principal philosophy used behind it is to route DNS response packets along the same path which was used by corresponding DNS request packet. Such routing is independent of the destination IP address present in the packet. This way, the malicious host responsible for launching DDoS attack will self-destruct itself. The results of the simulation showed that KarmaNet reduced the network delay by 41% when the network was experiencing a DDoS attack. Also, as any security mechanism comes at a cost, simulations of proposed mechanism shows that it also introduced additional delay of 8%–9% in getting DNS responses as compared to current DNS structure.
A Keyword Searching Algorithm For Search Engines
(IEEE, 2007) Gupta, Vishal
Search engines prominently use inverted indexing technique to locate the Web pages having the keyword contained in the users query. The performance of inverted index, fundamentally, depends upon the searching of keyword in the list maintained by search engines. This paper presents a new technique for keyword searching. It uses a trie data structure to index the keyword up to a certain optimum level. While searching a keyword, this index is used to get two offset values, in constant amount of time for every keyword, within which the keyword might lie. Using the two offsets, a binary search is initiated to locate the keyword in the list, and hence the Web pages containing the keyword. Research shows that subsequently increasing the levels of trie will increase the performance of retrieval but also increase the required memory. It also shows that on an average with indexing up to level 2 requires 56% less number of comparisons, as required by binary search, to search a keyword in the list.
Link Changes with Change in Demand in Flow Distribution Networks
(IEEE, 2016) Gupta, Vishal
Water Distribution Networks (WDNs) are the foundation and backbone of any city. There maintenance and energy costs demand a significant amount of planning. Judicious scheduling operations can prompt significant savings in energy and prevent disruptions in supply and damages. Water passes through a great deal of system hubs (like pumps, valves, tanks, and so on) while moving from source (reservoir) to individual customers. Such system turn into an uncommon instance of packet switched network, and can be modeled based on networking theory. Similar to bandwidth of each network link, every link in a WDN has a fixed and predefined capacity. Given a source and destination node, there can be a specific estimation of most extreme stream of water which is possible between them. In this paper, our aim is to study the link changes in WDN. Depending upon the change in demand at the destination node, the proposed algorithms recommend optimal modifications in the connecting links of the existing network to increase the maximum possible flow.
Mitigating DNS Amplification Attacks Using a Set of Geographically Distributed SDN Routers
(IEEE, 2018) Gupta, Vishal
Large DNS amplification attacks which overwhelm the victim's network bandwidth are a serious problem. In this paper, we propose a solution which can protect networks from these large DNS amplification attacks. The solution involves a set of geographically distributed routers, called a Barrier of Routers (BoR). Networks which want to protect themselves will route all their incoming and outgoing traffic through this barrier. The barrier scans all incoming traffic, drops attack traffic and sends the rest to the intended recipient. For some type of attacks, like DNS amplification attack, the barrier can mitigate attack traffic with almost full accuracy under the stated achievable assumptions. Therefore, the number of attack packets reaching the victim is negligible.
Mobile Data Offloading: Benefits, Issues, and Technological Solutions
(Springer, 2012) Rohil, Mukesh Kumar; Gupta, Vishal
Apart from voice services, data made its foray in cellular networks with 2.5G networks. Today, with 3G network already in place, the data requirements of mobile subscribers is very high. With the increasing demand for mobile internet and rich data services such as streaming media for audio and video, this data requirement is expected to multifold in near future. Correspondingly the existing network infrastructures will have to scale to satisfy this huge bandwidth demand in future. The simple solution for this is to build up new infrastructure. But huge investments are involved with it. So, network operators have started looking for the alternative ways of satisfying this data needs. Among many alternatives, mobile data offloading is a most promising one. This paper presents the extensive need, benefits, and technological solutions for Mobile data offloading.
Modeling user preferences for vertical handover in 3G-WLAN interworking environment on top of IEEE 802.11u
(IEEE, 2013) Rohil, Mukesh Kumar; Gupta, Vishal
In a heterogeneous networking environment vertical handover decision plays a very crucial role in the overall handover process. Many parameters and techniques have been proposed in the literature for selecting a best network available at a particular instance of time. Since user satisfaction is one of the ultimate aim of vertical handover process and different users can have different preferences on the same parameter, one of the vertical handover decision parameter is User-Preference. In this paper, limiting the scope to 3G-WLAN interworking environment and using Analytic Hierarchy Process (AHP), the problem of capturing user preferences on top of IEEE 802.11u is modeled. IEEE 802.11u is the ninth amendment to IEEE 802.11-2007 standard and allows interworking of Wireless Local Area Network (WLAN) with external networks. Using the proposed model, the ranking of available networks can be done based on only user preferences. These ranking values can further be used with other parameters (e.g. bandwidth, delay, jitter etc.) to select the best network for vertical handover. We also present the results of a survey among a group of users. This survey suggests the services which 802.11u compatible WLAN service providers should consider providing to users.
Natural language processing to query a Geographic Information System (India) knowledgebase
(Geospatial Media and Communications, 2009) Gupta, Vishal
In the work presented in this paper, a successful effort is made to answer the user’s English-like simple queries about geography of India and the user is not required to know about the structure of the database at logical level because the software is implemented using Logic Programming constructs and uses, knowledge-base, rather than a database. A user-interface system is developed which can accept queries, keyed-in in natural English language. It can further understand and interpret the meaning of the question asked by the given query. Finally the system can analyze and search the knowledgebase to answer the stated query, by reducing search space using artificial intelligence techniques. If the query is not understood by the system it reports to the users about the words not available in the knowledgebase and also reports the particular relations about the entities not being currently answered. The knowledgebase of about 32 K is stored about the following geographical entities and their inter-relationship that are related and limited to Indian peninsula:
Network discovery and user preferences for network selection in 3G-WLAN interworking environment
(IEEE, 2013) Gupta, Vishal
In a heterogeneous networking environment vertical handover decision plays a very crucial role in the overall handover process as wrongly selected network spoils the overall purpose of Always Best Connected (ABC). For it many decision models, based on diverse parameters and techniques, have been proposed. In this paper, following two requirements which most of such models require are emphasized: a) Network information other than that available in the corresponding network advertising frame to get the values of the decision parameters considered and b) User Preferences because it is the user satisfaction which is one of the ultimate aim of vertical handover process and different users can have different preferences on the same parameter. It is shown that how additional information can be stuffed in the Information Element's LENGTH field of 802.11 compatible beacon frame. Also, capturing user preferences is modeled primarily on the parameters derived from the fields added by IEEE 802.11u to the beacon frame. The proposed technique for it, called Analytic Hierarchy Process (AHP), is also made more effective by measuring its criticisms.
Network selection in 3G-WLAN interworking environment using TOPSIS
(IEEE, 2016) Gupta, Vishal
The expansion of wireless technologies and their pervasiveness has resulted in various network interfaces in mobile terminals. Therefore it is necessary for mobile terminals to implement vertical handover techniques which encourage the clients to move effectively and seamlessly among different diverse network systems. In vertical handover, selection of appropriate network is an extremely critical stage as wrongly chosen destination network ruins the entire novel purpose of vertical handover. This can successively lead to ping pong effect, under utilization of network resources, and dissatisfaction among users. This problem of network selection is very much related to Multiple Criteria Decision Making (MCDM) and can be modeled on various techniques given for it. In this paper, utilizing a MCDM technique called TOPSIS, an approach for destination network selection is proposed. The scope is limited to 802.11 destination networks. As a novel contribution, the list of parameters is selected from the perspective that either they are the part of IEEE 802.11 beacon frame or can be embedded in it using some beacon stuffing technique. In the later case we also give how many additional bits are required for stuffing them in the beacon frame. This makes our technique a practically usable one.