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A survey of mitigating routing misbehavior in mobile ad hoc networks

A survey of mitigating routing misbehavior in mobile ad hoc networks






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    A survey of mitigating routing misbehavior in mobile ad hoc networks A survey of mitigating routing misbehavior in mobile ad hoc networks Document Transcript

    • International Journal of ComputerComputerand Technology (IJCET), ISSN 0976 – 6367(Print),International Journal of Engineering EngineeringISSN 0976 – 6375(Online) Volume 1, Number 2, Sep - Oct (2010), © IAEMEand Technology (IJCET), ISSN 0976 – 6367(Print)ISSN 0976 – 6375(Online) Volume 1 IJCETNumber 2, Sep - Oct (2010), pp. 106- 117 ©IAEME© IAEME, http://www.iaeme.com/ijcet.html A SURVEY OF MITIGATING ROUTING MISBEHAVIOR IN MOBILE AD HOC NETWORKS Mrs. S. A. Nagtilak Department of Computer Engineering S.C.O.E, Pune, E-Mail: saranagtilak@yahoo.co.in Prof. U.A. Mande Asst. Professors, Departments of Computer Engineering S.C.O.E, Pune, E-Mail: uamande.scoe@sinhgad.eduABSTRACT The operation of MANETs does not depend on preexisting infrastructure or basestations. Network nodes in MANETs are free to move randomly. Therefore, the networktopology of a MANET may change rapidly and unpredictably. This paper presents theexisting methods to detect misbehavior in MANETs. Routing protocols used in such typeof networks generally based on the assumption that, all participating nodes will be fullycooperative. But, due to the open structure node misbehavior may exist and packet lossoccurs. Among them one type of misbehavior is that some nodes will take part in routingestablishment processes but they do not respond to forward data packets and simplydismiss the packets. This paper surveys the methods can be used for the misbehaviordetection of MANET.Keywords – 2ACK, SACK, S-TWOACK, beans, nuggetsI. INTRODUCTION MANET mobile ad hoc network as the name suggests consists of a bunch ofentities called as nodes or hosts which communicate with each other exchanginginformation with the help of intermediate devices called as routers. The links betweenthese so called nodes is generally invisible or called as wireless links. The structure ofsuch networks is not predefined or it does not depend on any base stations lonely but a lotof other entities are also involved in the entire communication process. The topology of 106
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976 – 6367(Print),ISSN 0976 – 6375(Online) Volume 1, Number 2, Sep - Oct (2010), © IAEMEsuch networks keeps on changing mainly due to a factor called as mobility. Networkclients in MANETs may move randomly. Therefore, the network topology of a MANETcan be change unpredictably and speedily. All network activities, for instance forwardingdata packets, and detecting the topologies which concern with nodes themselves forexecution either collectively or individually. Due to this changing topology packet loss isa common phenomenon. Any wireless network consists of a lot of nodes that interactwith each other exchanging information continuously. As these nodes have the flexibilityof moving from one place to other, there may be cases wherein a particular node which isa receiver for a particular packet, moves away from the range of sender. However thesender is not aware of this scenario and it might still keep on sending packets thus leadingto packet and data loss. The other case is a bit more interesting, whenever communication takes placebetween any two nodes there are a lot of nodes involved in this communication processacting as mediators. All these nodes agree to forward packets during the actualcommunication process but one of them actually turns selfish during the data transfer,this selfish node keeps on dropping packets as when received instead of forwarding it tothe next hop in the communication process. These selfish behavior results in packet lossand also the source is unaware of such misbehaving node in the path towards thedestination. And there is no such mechanism to detect this misbehaving node. The structure of a MANET totally depends on application and it can vary fromnetwork to network. For e.g. from a small static network which is highly powerconstrained to a large hugely dynamic network. Lots of techniques have been discoveredto avoid the misbehavior or selfishness among nodes. There has been a lot of improvements in the field of computer and wirelesstechnologies therefore there has been a lot of development expected in mobile wirelesscomputing typical applications of which can be used in military scenes, rescue operationsor where it is almost difficult to rely on wired network. MANETs are self organizableand configurable hence also known as multi hop wireless ad hoc networks, where thetopology of the network keeps on changing continuously. 107
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976 – 6367(Print),ISSN 0976 – 6375(Online) Volume 1, Number 2, Sep - Oct (2010), © IAEMEA. PACKET LOSS DUE TO ROUTING MISBEHAVIORS During data transfer in ad hoc networks, all the nodes in the network usually takepart in the communication process in order to increase or maximize the throughput.Therefore the more the number of nodes greater is the bandwidth and smaller is thenetwork partition with smaller paths. However it might also happen that a node hasagreed to fully cooperate in the communication process but later refuses to do so resultingin loss of packets because of its selfishness [14]. A selfish node which acts as selfish by dropping packets does so because it isunwilling to spend its battery life and CPU cycles and save its bandwidth. Such amisbehaving node launches a denial of service attack by simply dropping packets. Figure 1 Scenario for packet dropping and misrouting In some cases it might happen that the node which is dropping packets might havefault in the software running at its end. So the need is to focus on how this misbehavingnode in order to decrease the packet loss can be detected [2]. There are a lot of schemesavailable in order to detect the routing misbehavior in MANET’s which are as follows:i) The watchdog technique: In this scheme misbehaving nodes are detected by overhearing the wirelessmedium. The path rater technique, which is based on the watchdog’s output, allows nodesto avoid the use of the misbehaving nodes in any future route selections. However, thedrawback with watchdog technique is that it depends heavily on overhearing principal;therefore there is chance that it might fail to identify misbehavior in routing or raise falsealarms in cases where ambiguous collisions, receiver collisions are present, it might alsofail sometimes in cases for limited transmission power. 108
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976 – 6367(Print),ISSN 0976 – 6375(Online) Volume 1, Number 2, Sep - Oct (2010), © IAEMEii) ACK and SACK schemes: They are used to measure the usefulness of the current route and to takeappropriate action. For example, congestion control is based on the reception of the ACKand the SACK packets.[1]iii) TWOACK Scheme: The 2ACK and the TWOACK schemes have the following major differences: 1)the node which acts as receiver in the 2ACK scheme usually sends 2ACK packets for asmall amount of data packet which it has received, whereas, in the TWOACK scheme,TWOACK packets are acknowledged for every data packet received at the receivers end.But, however it was observed that sending acknowledgement for a fraction of datapackets received, improves the performance of 2ACK scheme when it comes to routingoverhead.iv) (S-TWOACK) scheme or Selective TWOACK: In this scheme every TWOACK packet will acknowledge or reply the receipt fornumber of data packets, whereas in the 2ACK scheme, a 2ACK packet onlyacknowledges one data packet. Because of such a small change, the 2ACK scheme gainseasy control on the trade-off that appears between the network performance and the costas compared to the S-TWOACK scheme.II. EXISTING METHODOLOGIES Routing protocols for MANETs are designed based on the assumption that allparticipating nodes are fully cooperative. Misbehaving nodes can be a significantproblem. The presence of selfish or malicious nodes degrades the efficiency of packetrelaying. It increases the packet delivery latency and the packet loss rate. Selfish nodeslead to network partitioning. Various techniques have been proposed to preventselfishness in MANETs. These schemes can be broadly classified into two categories:credit-based schemes and reputation-based schemes.A. Credit-Based Schemes The basic idea of credit-based schemes presented [6] is to provide incentives fornodes to faithfully perform networking functions. In order to achieve this goal, virtual(electronic) currency or similar payment system may be set up. Nodes get paid for 109
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976 – 6367(Print),ISSN 0976 – 6375(Online) Volume 1, Number 2, Sep - Oct (2010), © IAEMEproviding services to other nodes. When they request other nodes to help them for packetforwarding, they use the same payment system to pay for such services. The concept ofnuggets (also called beans) is used for payments for packet forwarding. There are twomodels which use nuggets are: the Packet Purse Model shown Figure 2 and the PacketTrade Model shown in Figure 3. In the Packet Purse Model, nuggets are loaded into thepacket before it is sent. The sender puts a certain number of nuggets on the data packet tobe sent. Each intermediate node earns nuggets in return for forwarding the packet. If thepacket exhausts its nuggets before reaching its destination, then it is dropped. In thePacket Trade Model, each intermediate node “buys” the packet from the previous nodefor some nuggets and “sells” it to the next node for more nuggets. Thus, eachintermediate node earns some nuggets for providing the forwarding service and theoverall cost of sending the packet is borne by the destination. In another implementation, each node maintains a counter termed the neglectcounter. The counter is decreased when the node sends packets of its own, butincreased when it forwards packets for the other nodes. The counter should be positivebefore a node is allowed to send its packet. Therefore, the nodes are encouraged tocontinue to help other nodes. Tamper resistant hardware modules are used to keep nodesfrom increasing the neglect counter illegally. Figure 2 Packet purse model. 110
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976 – 6367(Print),ISSN 0976 – 6375(Online) Volume 1, Number 2, Sep - Oct (2010), © IAEME Figure 3 Packet trade model. Another credit-based scheme, termed Sprite, has nodes that keep receipts of thereceived/forwarded messages. When the users have a fast connection to a CreditClearance Service (CCS), they report all of these receipts. The CCS then decides thecharge and credit for the reporting nodes. In the network architecture of Sprite, the CCSis assumed to be reachable through the use of the Internet, limiting the utility of Sprite.The main problem with credit-based schemes is that they usually require some kind oftamper-resistant hardware and/or extra protection for the virtual currency or the paymentsystem.B. Reputation-Based Schemes The second category of techniques to combat node misbehavior in MANETs isreputation-based presented by [2]. In such schemes, network nodes collectively detectand declare the misbehavior of a suspicious node. Such a declaration is then propagatedthroughout the network so that the misbehaving node will be cut off from the rest of thenetwork. The two modules under this category are watchdog and path rater shown in Fig4. Nodes operate in a promiscuous mode wherein the watchdog module overhears themedium to check whether the next-hop node faithfully forwards the packet. At the sametime, it maintains a buffer of recently sent packets. A data packet is cleared from thebuffer when the watchdog overhears the same packet being forwarded by the next-hopnode over the medium. If a data packet remains in the buffer for too long, the watchdogmodule accuses the next hop neighbor of misbehaving. Thus, the watchdog enablesmisbehavior detection at the forwarding level as well as the link level. Based on thewatchdog’s accusations, the path rater module rates every path in its cache and 111
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976 – 6367(Print),ISSN 0976 – 6375(Online) Volume 1, Number 2, Sep - Oct (2010), © IAEMEsubsequently chooses the path that best avoids misbehaving nodes. Due to its reliance onoverhearing, however, the watchdog technique may fail to detect misbehavior or raisefalse alarms in the presence of ambiguous collisions, receiver collisions, and limitedtransmission power. The CONFIDANT protocol [7] is another example of reputation-based schemes.The protocol is based on selective altruism and utilitarianism, thus making misbehaviorunattractive. CONFIDANT consists of four important components—the Monitor, theReputation System, the Path Manager, and the Trust Manager. They perform the vitalfunctions of neighborhood watching, node rating, path rating, and sending and receivingalarm messages, respectively. Each node continuously monitors the behavior of itsfirst-hop neighbors. If a suspicious event is detected, details of the event are passed tothe Reputation System. Depending on how significant and how frequent the event is, theReputation Figure 4 Watchdog & Path rater. System modifies the rating of the suspected node. Once the rating of a nodebecomes intolerable, control is passed to the Path Manager, which accordingly controlsthe route cache. Warning messages are propagated to other nodes in the form of an Alarmmessage sent out by the Trust Manager. The Monitor component in the CONFIDANTscheme shown in Figure 5 observes the next hop neighbor’s behavior using theoverhearing technique. This causes the scheme to suffer from the same problems as thewatchdog scheme. 112
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976 – 6367(Print),ISSN 0976 – 6375(Online) Volume 1, Number 2, Sep - Oct (2010), © IAEMEC. End-to-End Acknowledgment Schemes There are several schemes that use end-to-end acknowledgments (ACKs) to detectrouting misbehavior or malicious nodes in wireless networks. In the TCP protocol, end-to-end acknowledgment is employed. Suchacknowledgments are sent by the end receiver to notify the sender about the reception ofdata packets up to some locations of the continuous data stream. The SelectiveAcknowledgment (SACK) technique [3] is used to acknowledge out-of-order data blocks. Figure 5 CONFIDANT Scheme. The 2ACK technique differs from the ACK and the SACK schemes in the TCPprotocol in the following manner: The 2ACK scheme tries to detect those misbehavingnodes which have agreed to forward data packets for the source node but refuse to do sowhen data packets arrive. TCP, on the other hand, uses ACK and ACK to measure theusefulness of the current route and to take appropriate action. In order to identify malicious routers that draw traffic toward them but fail tocorrectly forward the traffic, the secure trace route protocol is proposed. The normal traceroute protocol allows the sender to simply send packets with increasing Time-To- Live(TTL) values and wait for a warning message from the router at which time the packet’sTTL value expires. The secure trace route protocol authenticates the trace route packetsand disguises them as regular data packets. In secure trace route scheme, binary search is initiated on faulty routes.Asymptotically, log (n) probes are needed to identify a faulty link on a faulty n-hop route.This technique only works with static misbehaviors and needs to disguise the probingmessages as regular routing control packets. Once a link is identified as faulty, the linkweight is increased so that future link selections will avoid this link. 113
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976 – 6367(Print),ISSN 0976 – 6375(Online) Volume 1, Number 2, Sep - Oct (2010), © IAEME The Best-effort Fault-Tolerant Routing (BFTR) scheme [16] also employs end-to-end ACKs. The BFTR scheme continuously monitors the quality (i.e., packet deliveryratio) of the path in use. This is compared with the predefined expected behavior of goodroutes. If the behavior of the route in use deviates from the behavior of good routes, it ismarked as “infeasible” and a new route is used. Since BFTR throws out the entire routebefore detecting the misbehaving nodes, the newly chosen route may still include thesame misbehaving nodes. Even though the new route will be detected as infeasible by thesource after a period of observation time, data packet loss will occur in traffic flows whenusing protocols such as UDP. Such a repeated detection process is inefficient. In contrastwith BFTR, it is try to identify such misbehaving links in this work. Therefore, moreaccurate information on routing misbehavior can be obtained in the 2ACK scheme.III. COMPARISON WITH THE EXISTING SCHEMES Compared with the above schemes, the 2ACK scheme doesn’t depend on end-toend acknowledgment. Instead, the 2ACK scheme tries to detect misdemeaning links asthe links are being used. Such a proactive detection approach results in quicker detectionand identification of misdemeaning links. In such a combined scheme, the Multi-Hoptransmission and the monitoring processes are turned on only when routing carry outfacedegrades. It will further reduce the routing overhead of the 2ACK scheme. A scheme to choose routes based on the reliability index of each outgoingneighbor has each node maintaining a table of reliability indices of its neighbors. Thistype of reliability index indicates the previous success or failure experience of packettransmissions through neighboring nodes. For example, a successful point-to-pointtransmission will give output in an increase of the reliability index of the neighborassociated with the route. When selecting path for data transmissions, nodes prefer thoserooted at the neighbors with higher reliability indices. Since a sender searches all possiblepath from its immediate neighbors, the overall reliability of the selecting path depends onhow the neighbors select the rest of the route.As compared to the watchdog, the 2ACK scheme has the following advantages: Ambiguous Collisions: Ambiguous or doubtful collisions may occur at node N1.When a well behaved node N2 forwards the data packet toward N3, it is possible that N1 114
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976 – 6367(Print),ISSN 0976 – 6375(Online) Volume 1, Number 2, Sep - Oct (2010), © IAEMEcannot overhear the transmission due to another concurrent transmission in N1sneighborhood. The 2ACK technique solves this problem by requiring N3 to send a Multi-Hop packet explicitly. Receiver Collisions: Receiver or acceptor collisions take place in case ofoverhearing techniques when N1 overhears the data packet being forwarded by N2, butN3 fails to get the packet due to collisions in its neighborhood. The data packets will notbe retransmitted by a misbehaving N2 because retransmission requires extra energy.Again, due to the explicit Multi-Hop packets our 2ACK scheme overcomes this problem. Limited Transmission Power: A misbehaving N2 may engineer its transmissionpower in such a way that N1 can overhear its transmission but not N3 such that, thisproblem matches with the Receiver Collisions problem. It goes to a level of threat onlywhen the distance between N1 and N2 is less than the distance between N2 and N3. The2ACK scheme does not suffer from limited transmission power problem. Limited Overhearing Range: In order to transmit data to N3 a well-behaved N2could apply low level of power transmission. Due to N1s limited overhearing range, itwill not overhear the transmission successfully and will thus infer that N2 ismisbehaving, causing a false alarm. Both this problem occur due to the potentialasymmetry between the communication links. The 2ACK scheme is not affected bylimited overhearing range problem. The 2ACK scheme of detecting routing misbehavior is different from theTWOACK and SACK schemes present in the TCP protocol in the following manner: The 2ACK technique identifies misbehaving nodes which had agreed to forwarddata packets originating from the source node but later refuse to do so during actual datatransfer. On the other side, the TCP protocol uses SACK and ACK to find the benefit ofthe current route and to take the required action. 2ACK scheme does not depend on end-to-end acknowledgment. Such a 2ACK scheme may not exist in some traffic flows forinstance UDP protocol. Such a proactive approach of detection results in faster detectionof misbehaving links. 115
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976 – 6367(Print),ISSN 0976 – 6375(Online) Volume 1, Number 2, Sep - Oct (2010), © IAEMEIV. CONCLUSION The 2ACK scheme which helps detect misbehavior by a two hopacknowledgement. The 2ACK scheme is a network-layer technique to detectmisbehaving links and to mitigate their effects. The 2ACK scheme detects misbehaviorthrough the use of a new type of acknowledgment packet, termed 2ACK. A 2ACK packetis assigned a fixed route of two hops (three nodes N1, N2, N3), in the opposite directionof the data traffic route. This technique identifies misbehaving nodes which had agreed toforward data packets originating from the source node but later refuse to do so duringactual data transfer and it helps to reduce the routing overhead.V. FUTURE WORK The 2ACK scheme can be implemented which helps detect misbehavior by a twohop acknowledgment. The 2ACK scheme for detecting routing misbehavior is consideredto be network-layer technique for mitigating the routing effects. The 2ACK schemeidentifies misbehavior in routing by using a new acknowledgment packet, called 2ACKpacket. The 2ACK technique is based on a simple 2-hop acknowledgment packet that issent back by the receiver of the next-hop link. The 2ACK scheme can be used as an add-on technique to routing protocols such as OLSR in MANETs.REFERENCES[1] Aad I., Hubaux J.-P., and Knightly E-W., “Denial of Service Resilience in Ad Hoc Networks,” Proc. MobiCom, pp. 202-215, 2004.[2] Baker M, Giuli T., Lai K. and Marti S., “Mitigating Routing Misbehavior in Mobile Ad Hoc Networks,” Proc. MobiCom, pp. 255-265, Aug. 2000.[3] Balakrishnan K., Deng J., and Varshney P. K., “TWOACK: Preventing Selfishness in Mobile Ad Hoc Networks,” Proc. IEEE Wireless Comm. and Networking Conf. (WCNC ’05), pp.2137-2142 Mar. 2005.[4] Buttyan L. and Hubaux J. -P., “Security and Cooperation in Wireless Networks,” http://secowinet.epfl.ch/, 2006.[5] Buttyan L.and Hubaux J.-P., “Stimulating Cooperation in Self-Organizing Mobile Ad Hoc Networks,” ACM/Kluwer Mobile Networks and Applications, vol. 8, no. 5, pp. 579-592, 2003. 116
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976 – 6367(Print),ISSN 0976 – 6375(Online) Volume 1, Number 2, Sep - Oct (2010), © IAEME[6] Buttyan L. and Hubaux J.-P., “Enforcing Service Availability in Mobile Ad-Hoc WANs,” Proc. MobiHoc, pp, 255-265, Aug. 2000.[7] Buchegger S. and Le Boudec J.-Y., “Performance Analysis of the CONFIDANT Protocol: Cooperation of Nodes, Fairness in Dynamic Ad-Hoc Networks,” Proc. MobiHoc, pp. 226-236, June 2002.[8] Buttyan L., Hubaux J.-P.,and Jakobsson M., “A Micropayment Scheme Encouraging Collaboration in Multi-Hop Cellular Networks,” Proc. Financial Cryptography Conf., pp. 609-612, Jan. 2003.[9] Chiasserini C.F., Nuggehalli P., Srinivasan V., and Rao R.R., “Cooperation in Wireless Ad Hoc Networks,” Proc. INFOCOM, vol.2, pp. 808-817 Mar.-Apr. 2003.[10] Dipak Ghosal, Rose P. Tsang, and Stephen Mueller. “Multipath Routing in Mobile Ad Hoc Networks: Issues and Challenges in Performance tools and applications to networked systems” revised tutorial lectures 2004, Volume 2965, Pages 209-234, Year of Publication :2004, ISBN 3-540-21945-5[11] Floyd S., Mathis M., Mahdavi J., and Romanow A., “RFC 2018 TCP Selective Acknowledgement Options,” technical report, PSC, LBNL, Sun Microsystems, Oct. 1996.[12] Jing Deng, Kejun Liu, Pramod K. Varshney, Fellow and Kashyap Balakrishnan. An Acknowledgment-Based Approach for the Detection of Routing Misbehavior in MANETs IEEE Transactions on Mobile Computing, Volume 6 , Issue 5 (May 2007) Pages 536-550, Year of Publication: 2007, ISSN: 1536-1233[13] Miranda H. and Rodrigues L., “Preventing Selfishness in Open Mobile Ad Hoc Networks,” Proc. Seventh CaberNet Radicals Workshop, Oct. 2002.[14] Nahrstedt K. and Xue Y., “Providing Fault-Tolerant Ad-Hoc Routing Service in Adversarial Environments,” Wireless Personal Comm., vol. 29, nos. 3-4, pp. 367- 388, 2004.[15] Sundararajan T.V.P., Dr.Shanmugam A.” Performance Analysis of Selfish Node Aware Routing Protocol for Mobile Ad Hoc Networks”, ICGST-CNIR Journal, Volume 9, Issue 1, July 2009 117