Investigating Performance of Extended Epidemic Routing Protocol of DTN under Routing Attack

Investigating Performance of Extended Epidemic Routing Protocol of DTN under Routing Attack Harminder Singh Bindra 1, A L Sangal 2 1 Research Scholar, Department of CSE, DR B R Ambedkar National Institute of Technology Jalandhar, India 2 Professor, Principal, DAV Institute of Engineering and Technology, Jalandhar, India Abstract - Nodes in the DTN work on the foundation of cooperation in the network. When working in a cooperative manner, these nodes consume some network resources like bandwidth, buffer space etc. Like any other networks, DTNs are also prone to the malicious nodes and different attacks. In this work, we have proposed an attack model comprising of falsification of extended routing protocol metadata information combined with drop all attack. We have proposed the attack model definition and analyzed the performance of extended Epidemic routing protocol of DTN under this attack model. From the simulation results, we analyzed that the delivery probability of extended Epidemic routing protocols is greatly affected by the proposed attack model whereas the DTN routing protocols are proved to be robust against the individual attacks when implemented independently of each other. Keywords: Delay Tolerant Networks, Epidemic, Spray & Wait, Prophet, Delivery probability, Average latency, Overhead ratio. 1 Introduction Traditionally, data networks are sculpted by linking graphs whereby the continuation of at least one end-to-end passage among any source-destination duet is endlessly certain. In these networks, any random bond between two network nodes is thought to be bidirectional sustaining symmetric data rates with slight error chances and latency (i.e. Round-trip time is in the order of milliseconds). In these networks, packets are not thought to survive in a node s buffer for a prolonged time period. On the foundation of these fundamental suppositions, the Internet was planned and its most universally used protocols, predominantly the TCP/IP protocol suite, were planned. On the other hand, these suppositions do not clutch when scheming existing and newly budding wireless networks, particularly those which are to be deployed in acute environments (e.g. Battlefields, volcanic regions, deep oceans, deep space, developing regions, etc.). Under such demanding environment, these networks suffer from extensive delays, acute bandwidth limitations, widespread mobility of nodes, recurrent power outages and frequent communication hindrance. Wireless networks operational under these demanding conditions experiences connectivity which becomes noticeably discontinuous and no uninterrupted end-to-end path(s) between any source-destination pair can be assured [1]. Popular examples of such irregularly connected networks (ICNs) scenarios are satellites, deep space probes, Wireless Sensor Networks (WSNs), Mobile Wireless Sensor Net- works (MWSNs) and Sensor/Actuator Networks (SANs) deployed in acute regions, Mobile Ad-Hoc Networks (MANETs) in general consisting of nodes (e.g. GPSs, PDAs, Cellular Phones, Tracking devices, Laptops, etc.) mounted over endlessly moving objects [1]. Numerous study interests spotlight on developing new approaches for routing in delay tolerant network atmosphere. These routing schemes in general use the store-carry-and- forward approach, where intermediate nodes keep the message until encounter other nodes to set up new links in the path to the destination [2]. DTN Routing protocols can be generally categorized on two bases: (1) on the basis of the number of copies and (2) on the basis of knowledge of future contact opportunities and message patterns. On the basis of the number of copies, we have Single-copy routing schemes which use only one copy per message and significantly reduce the resource requirements but suffer from long delays and low delivery ratios. Other one is Multi-copy routing schemes has a high probability of delivery and lower delays at the cost of buffer space and more message transfers. This work is related to the security issues of the extended routing protocols [20] and studies the robustness of these protocols against the attack model proposed in this work. Section 2 summarizes prior related work on routing in disrupted environment and the attacks on the delay tolerant networks. Section 3 details the system model. In this section, the details about the security assumptions, routing model and simulation settings are discussed. Section 4 detail the attack model proposed in this paper. This section emphasis on the step by step description of the attack model for this work. In Section 5, results obtained from the simulation study are discussed. In this, the results are discussed for

the three metrics i.e. delivery probability, overhead ratio and average latency under the varying buffer size of the nodes. Section 6 concludes the study and lists the results obtained in this study. 2 RELATED WORK Basic DTN routing algorithms rely only on node movement, and no other information is used for the establishment of the communication link. Examples of primary DTN routing are Custody Transfer and Epidemic Routing. In order to get better performance of DTN routing, numerous mechanisms have been implemented in diverse DTN routing protocols [1], [2], [3], [4], [5], [6]. These mechanisms often take account of duplication of packets to several nodes so as to raise the probability of delivery and to lessen the delivery latency. In a sole contact, only restricted packets may be exchanged among two portable nodes. As an effect, the orders of packet transmit, which depends on the precedence a node acquaintances with every packet, has momentous impact on the general performance. Replication- based DTN routing protocols vary principally on how each packet s precedence is determined. Software of DTN study projects uses an arbitrary algorithm to reproduce node movement while mobility in actual existence has a knowable pattern. Certain DTN routing algorithms are designed to exploit this expected action of node mobility for predicting message delivery in a probabilistic approach [7]. There are numerals of additional proactive approaches to routing which are made achievable by stronger assumptions such as awareness of connectivity model and be in command of peer movement [8-14]. By and large the routing protocols of DTN deal with their buffers as first-in-first-out (FIFO) queues [15]. A further approach is Drop Least Encountered (DLE) algorithm [16] which proposed dropping messages with the lowest likelihood of delivering and various work deployed this dropping technique [7,10,12,17]. The problem associated to the existence of copy of the previously delivered communication in multi copy routing design was studied by Bindra et. al. in [18]. It was assessed that if the copies are removed at the same instance when the one of the data bundle is conveyed then there is the possibility for step up in the performance of the routing protocols. Further Bindra et. al. in [19] proposed a message deletion policy for multi-copy routing scheme and analyzed the buffer occupancy of the nodes under this extended routing protocol (with proposed message deletion policy). Simulation results show that the extended routing protocol proposed in this work greatly relaxes the buffers of the nodes enabling them to handle more and more messages, which in turn improve the efficiency of the routing protocol. It also helps in preventing the nodes from buffer overflow problem and relaxes the resource utilization of the nodes. In year 2013, Bindra et. al. in [20] studied the performance of different routing protocol with the proposed buffer management scheme. This scheme helped in preventing the nodes from excessive utilization of resources. It was analyzed that the extended routing protocols (with this new buffer management scheme) performed with improved delivery probability values with reduced overhead ratio and lower average latency value. Performance of DTN routing protocols not only depend on the factors considered above but also depend on the attacks by the malicious nodes. There are numerous studies on securing the routing protocols of MANETs which focuses on securing the path establishment process [21], [22], [23], [24], [25], [26]. But these schemes cannot be used in securing the DTN as in DTN there is intermittent connectivity and no end-to-end path exist for all sourcedestination pair at all the time. 3 SYSTEM MODEL In this section, we describe the system model of the network used for the analysis. This section also explains the security assumptions, mobility model, scenario, interface, node group, message creation specific settings. We evaluated the robustness of Extended routing protocols of DTN in the presence of attacking node. All the evaluations were performed using our simulator modified from ONE simulator [28], a simulator developed specifically for the DTN simulations. 1.1 Security Assumption In this work, we have assumed that the relay nodes do not perform any authentication on the authenticity of the packets. Due to this non availability of this authentication service, the malicious nodes can add the fake metadata into the network i.e. the malicious nodes can add false delivery information of the packets into the network. Another assumption made for this study is the lack of global knowledge of topology of the network to the nodes of the network. If this information is available in the network, the malicious nodes can perform much more damage to the routing performance. We have shown that, even in the absence of this information, yet our proposed attack model degrades the performance of the routing protocols to a great extent. 1.2 Routing Model The routing protocol used in our evaluation is the extended version of Epidemic Routing Protocol [20]. The considered protocol is a replication-based DTN routing protocol. MaxProp which is also a replication based protocol has been shown to provide robustness against various attacks [17]. It offers better throughput than several other strategies such as Epidemic [1], Prophet [3] and Spray and Wait [2]. The overall routing model

implemented is shown in figure 1 and 2. Fig 1: Flowchart for the base Routing Protocols of DTN 4 ATTACK MODEL In [27], four general attacks Drop All, Random flooding, Invert routing metadata, and Acknowledgement counterfeiting were experimentally shown to be ineffective. Although the above attacks may be ineffective, many variant of these attacks are still possible. In addition, these attacks can be pooled to support each other. Our proposed attack consists of falsification of extended routing protocol metadata information combined with drop all attack. In our extended DTN routing protocol, the network wide message delivery information is propagated to remove the existing replicas of the delivered information [20]. But if the malicious nodes are present in the network, they can inject the false delivery information Fig 2: Flowchart for the Extended Routing Protocol of DTN in the network about the packets present in the buffer of this node and drop all the packets which are present in the buffer. The detailed attack model is represented below. The figure 3(a) shows the behavior of normal node. In normal nodes, when two nodes come in the communication range of each other, they populate and exchange the del_msgs lists. Further details about the del_msgs lists and normal behavior of nodes are given in work by Bindra et al. [20]. But if one of the connected nodes or both are malicious, then the behavior of malicious node is depicted in figure 3(b). When these nodes get connected, first of all it reads all the messages from its collection and adds their ids in the del_msgs list and drop all the messages.

Figure 3: a) Behavior of Normal Node 5 RESULTS AND DISCUSSION In this section, we discuss the results of the simulations of the system model and attack model presented in section 3 and section 4. To study the attack Figure 3: b) Behavior of Malicious Node model, simulations are carried out in our simulator that was modified from ONE simulator [28], simulator designed for DTN simulations. The detailed simulation setup is presented in Table 1. Table 1: Simulation Configuration Scenario Setting Name simulateconnection updateinterval endtime Default_scenario True 0.1 s 43200 s Interface Specific Setting Name Type Transmit Speed Transmit Range btinterface SimpleBroadcastInterface 250k 30 m Node Group Specific Settings Shortest Path Movement Extended Version of [Epidemic] 5-35M 300, 900 s 1 btinterface 0.5, 1.5 m/s 120 mins 40 Movement Model Router Buffer size Wait Time No of Interfaces interface1 Speed Msg Ttl No of Hosts Message Creation Parameters

Events.nr of 1 Events1.class Events1.interval Events1.size Events1.hosts Events1.prefix Message Event Generator 15,30 s 250k, 2M 0, 39 M Movement Model Settings MovementModel.rngSeed MovementModel.worldSize MovementModel.warmup 1 4500, 3400 m 1000 s Style Bold and Italic : Category Heading A. The Impact on Delivery Probability From the fig 4 (a), we analyze that the presence of the attacker node reduces delivery probability of extended protocols. In case of epidemic routing protocol, there is 23% decrease in delivery probability when only 4% of attacker nodes are present. If we increase % of attacking nodes, there is larger decrease in delivery probability. B. The Impact on Overhead Ratio From fig 4(b), it is clear that there is a significant increase in the Over Head Ratio when proposed attack is implemented. When 20% attacking nodes are present, there Bold: Attribute Italic : Attribute value Attribute which is varied is 115% increase in overhead ratio for epidemic routing C. The Impact on Average Latency Results obtained from the simulative study show interesting results for the average latency. Figure 4(c) show that there is an improvement in Average Latency experienced by delivered message. This is because of fact that now buffer is further relaxed as more packets are being deleted due to proposed attack model. Thus remaining packets have to wait for less amount of time in buffer queue. It is observed that average latency value improves by 65% for epidemic routing when20% attacking nodes are added. (a) (b) (c) Figure 4: (a) Delivery Probability under attack model (b) Overhead Ratio under Attack model (c) Average Latency under attack model need of the authentication service in the routing protocols so that these attacks can be prevented. 6 CONCLUSION Routing metadata that are employed in DTN routing to improve resource utilization can be exploited by attackers to improve the effectiveness of attacks. We have presented an attacks model - comprising of falsification of extended routing protocol metadata information combined with drop all attack - that demonstrates how attackers can exploit routing metadata to improve the effectiveness of attacks. Earlier works from the literature say that the DTN routing protocols are robust to the routing attacks. But the attack model proposed above which is a combination of two attacks is effective enough to degrade the performance of the extended routing protocols of DTN. The simulation results show that the addition of attacker nodes in the network decreases the delivery probability, increases the overhead ratio and decreases the average latency. From the results, it can be analyzed that the effectiveness of the attack increases when the combination of the attacks is employed in collaboration. So from these results we can conclude that there is the In the future, we will try to provide the preventive measures or the authentication service to prevent the attacks and to preserve the performance of these extended routing protocols even in the presence of the attacking nodes. REFERENCES [1] A. Vahdat and D. Becker, Epidemic routing for partially connected ad hoc networks, Department of Computer Science, Duke University, Durham, NC, Tech. Rep., 2000. [2] T. Spyropoulos, K. Psounis, and C. S. Raghavendra, Spray and wait: an efficient routing scheme for intermittently connected mobile networks, in WDTN 05: Proceeding of the 2005 ACM SIGCOMM workshop on Delay-tolerant networking. New York, NY, USA: ACM Press, 2005, pp.252 259. [3] A. Lindgren, A. Doria, and O. Schele n, Probabilistic routing in intermittently connected

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