Survey on Mobile Adhoc Networks

Transcription

1 International Journal of Computer Systems (ISSN: ), Volume 02 Issue 12, December, 2015 Available at Survey on Mobile Adhoc Networks B. Madhuranjani, Dr. E. Rama Devi Department of Computer Science, NGM College, Pollachi, India Abstract Mobile ad hoc networks (MANETs) is an infrastructure-less, dynamic network consisting of a collection of wireless mobile nodes that communicate with each other without the use of any centralized authority. Due to its fundamental characteristics, such as wireless medium, dynamic topology, distributed cooperation, MANETs is vulnerable to various kinds of security attacks like worm hole, black hole, rushing attack etc. In this paper mobile ad-hoc networks are studied based on the important features like its characteristics, challenges, application, security goals and security attacks. Keywords: Mobile ad-hoc network (MANET), Security attacks, Dynamic network. I. INTRODUCTION A Mobile Adhoc Network is a collection of independent mobile nodes that can communicate to each other via radio waves. The mobile nodes that are in radio range of each other can directly communicate, whereas others need the aid of intermediate nodes to route their packets. Each of the node has a wireless interface to communicate with each other. These networks are fully distributed, and can work at any place without the help of any fixed infrastructure as access points or base stations. In operation, the nodes of a MANET do not have a centralized administration mechanism. It is known for its routable network properties where each node act as a router to forward the traffic to other specified node in the network. Fig 1 Simple Architecture of MANET A. Types of MANET There are different types of MANETs including: In VANETs - Intelligent Vehicular ad hoc networks make use of artificial intelligence to tackle unexpected situations like vehicle collision and accidents. Vehicular ad hoc networks (VANETs) - Enables effective communication with another vehicle or helps to communicate with roadside equipments. Internet Based Mobile Ad hoc Networks (imanet) - helps to link fixed as well as mobile nodes. B. MANET characteristics (1) Distributed operation: There is no background network for the central control of the network operations, the control of the network is distributed among the nodes. The nodes involved in a MANET should cooperate with each other and communicate among themselves and each node acts as a relay as needed, to implement specific functions such as routing and security. (2) Multi hop routing: When a node tries to send information to other nodes which is out of its communication range, the packet should be forwarded via one or more intermediate nodes. (3) Autonomous terminal: In MANET, each mobile node is an independent node, which could function as both a host and a router. (4) Dynamic topology: Nodes are free to move arbitrarily with different speeds; thus, the network topology may change randomly and at unpredictable time. The nodes in the MANET dynamically establish routing among themselves as they travel around, establishing their own network. (5) Light-weight terminals: In maximum cases, the nodes at MANET are mobile with less CPU capability, low power storage and small memory size. (6) Shared Physical Medium: The wireless communication medium is accessible to any entity with the appropriate equipment and adequate resources. Accordingly, access to the channel cannot be restricted. C. Advantages They provide access to information and services regardless of geographic position. These networks can be set up at any place and time. 576 International Journal of Computer Systems, ISSN-( ), Vol. 02, Issue 12, December, 2015

2 These networks work without any pre-existing infrastructure. D. Disadvantages Some of the disadvantages of MANETs are: Limited resources. Limited physical security. Intrinsic mutual trust vulnerable to attacks. Lack of authorization facilities. Volatile network topology makes it hard to detect malicious nodes. Security protocols for wired networks cannot work for ad hoc networks. II. ARCHITECTURE OF MANET The architecture of Mobile Ad-hoc Network (MANET) is shown in figure. The network architecture is grouped into main three categories: Enabling technologies; Networking; Middleware and applications A. Enabling Technology Depending on their coverage area, these technologies are classified into several classes: Body (BAN), Personal (PAN), Local (LAN), Metropolitan (MAN) and Wide (WAN) area networks. A body area network (BAN) is strongly connected with wearable computers. A wearable computer distributes on the body its components like as head mounted displays, microphones, earphones, etc., and the BAN provides the connectivity among these devices. With respect to the human body range, the communicating range of a BAN is 1 2 m. The Personal area networks (PAN) connect the mobile devices which are carried by users to other mobile and stationary devices. A PAN communicating range is typically up to 10 m. Fig 2: A simple MANET architecture Wireless LANs (WLANs) support m communication range for a single building, or a cluster of buildings. Wide- and Metropolitan-area (WAN-MAN) ad hoc networks are mobile multi-hop wireless networks that face many challenges which are still to be solved (e.g., addressing, routing, location management, security, etc.), and their availability is not on immediate horizon. B. Networking In MANET, most of the main functionalities of the Networking protocols need to be re- designed for the self organizing, dynamic, volatile, peer-to-peer communication environment. The main target of networking protocols is to use the one-hop transmission services which are provided by the enabling technologies to construct end-to-end (reliable) delivery services, from a sender to one (or more) receiver(s). In case of establish an end-to-end communication; the sender needs to locate the receiver within the network. The main aim of a location service is to dynamically map the logical address of the (receiver) device to its current location in the network. C. Middleware & Applications In the previous year the military oriented, non-military applications of MANET have also grown substantially since then. Especially in the past few years, with the rapid development in mobile ad hoc networking research, mobile ad hoc networks have attracted considerable attention and interests from commercial business industry, as well as the standards community. The introduction of new technologies like as the WiFi, Bluetooth, IEEE , WiMAX and HyperLAN greatly facilitates the deployment of ad hoc technology, and new ad hoc networking applications appeared mainly in specialized fields such as emergency services, disaster recovery and environment monitoring. In addition, MANET flexibility makes this technology attractive for several applicative scenarios like, for example, in personal area networking, home networking, law enforcement operation, search and- rescue operations, commercial and educational applications, sensor networks. Mobile ad hoc systems currently developed adopt the approach of not having a middleware, but rather rely on each application to handle all the services it needs. III. MANET VULNERABILIES Vulnerability is a weakness in security system. A particular system may be vulnerable to unauthorized data manipulation because the system does not verify a user s identity before allowing data access. MANET is more vulnerable than wired network. Some of the vulnerabilities are as follows: (1)Lack of centralized management: MANET doesn t have a centralized monitor server. The absence of management makes the detection of attacks difficult because it is not east to monitor the traffic in a highly dynamic and large scale ad-hoc network. (2) No predefined Boundary: In mobile ad- hoc networks we cannot precisely define a physical boundary of the network. The nodes work in a nomadic environment where they are allowed to join and leave the wireless network. As soon as an adversary comes in the radio range of a node it will be able to communicate with that node. (3) Cooperativeness: Routing algorithm for MANETs usually assumes that nodes are cooperative and non- 577 International Journal of Computer Systems, ISSN-( ), Vol. 02, Issue 12, December, 2015

3 malicious. As a result a malicious attacker can easily become an important routing agent and disrupt network operation. (4) Limited power supply: The nodes in mobile ad-hoc network need to consider restricted power supply, which will cause several problems. A node in mobile ad-hoc network may behave in a selfish manner when it is finding that there is only limited power supply. (5) Adversary inside the Network: The mobile nodes within the MANET can freely join and leave the network. The nodes within network may also behave maliciously. This is hard to detect that the behavior of the node is malicious. Thus this attack is more dangerous than the external attack. IV. MANET ROUTING PROTOCOLS Ad-Hoc network routing protocols are commonly divided into three main classes; Proactive, reactive and hybrid protocols as shown in figure hierarchical architecture where each node has to maintain additional topological information requiring extra memory. V. CLASSIFICATION OF SECURITY ATTACKS The attacks can be categorized on the basis of behavior of the attack i.e. Passive or Active attack (1) Passive attacks: A passive attack does not alter the data transmitted within the network. But it includes the unauthorized listening to the network traffic or accumulates data from it. Passive attacker does not disrupt the operation of a routing protocol but attempts to discover the important information from routed traffic. Eavesdropping: Eavesdropping is another kind of attack that usually happens in the mobile ad hoc networks. It aims to obtain some confidential information that should be kept secret during the communication. The information may include the location, public key, private key or even passwords of the nodes. Because such data are very important to the security state of the nodes, they should be kept away from the unauthorized access. Traffic Analysis & Monitoring: Traffic analysis attack adversaries monitor packet transmission to infer important information such as a source, destination, and source-destination pair. Fig 3: Classification of MANET Routing Protocols (1) Proactive Protocols: Proactive or table-driven routing protocols. In proactive routing, each node has to maintain one or more tables to store routing information, and any changes in network topology need to be reflected by propagating updates throughout the network in order to maintain a consistent network view. Example of such schemes are the conventional routing schemes: Destination sequenced distance vector (DSDV). They attempt to maintain consistent, up-to-date routing information of the whole network. It minimizes the delay in communication and allow nodes to quickly determine which nodes are present or reachable in the network. (2) Reactive Protocols: Reactive routing is also known as on-demand routing protocol since they do not maintain routing information or routing activity at the network nodes if there is no communication. If a node wants to send a packet to another node then this protocol searches for the route in an on-demand manner and establishes the connection in order to transmit and receive the packet. The route discovery occurs by flooding the route request packets throughout the network. Examples of reactive routing protocols are the Ad-hoc On-demand Distance Vector routing (AODV) [11] and Dynamic Source Routing (DSR). (3) Hybrid Protocols: They introduce a hybrid model that combines reactive and proactive routing protocols. The Zone Routing Protocol (ZRP) is a hybrid routing protocol that divides the network into zones. ZRP provides a Fig 4 Active & Passive attacks in MANET (2) Active attacks: Active attacks are very severe attacks on the network that prevent message flow between the nodes. However active attacks can be internal or external. Active external attacks can be carried out by outside sources that do not belong to the network. Internal attacks are from malicious nodes which are part of the network, internal attacks are more severe and hard to detect than external attacks. These attacks generate unauthorized access to network that helps the attacker to make changes such as modification of packets, DoS, congestion etc. Active attacks are classified into three groups: Dropping Attacks: Compromised nodes or selfish nodes can drop all packets that are not destined for them. Dropping attacks can prevent end-to-end communications between nodes. Modification Attacks: These attacks modify packets and disrupt the overall communication between network nodes. Sinkhole attacks are the example of modification attacks. 578 International Journal of Computer Systems, ISSN-( ), Vol. 02, Issue 12, December, 2015

4 Fabrication Attacks: In fabrication attack, the attacker send fake message to the neighbouring nodes without receiving any related message. A. Physical layer attacks Eavesdropping is the intercepting and reading of messages and conversations by unintended receivers. The mobile hosts in mobile ad hoc networks share a wireless medium. The majorities of wireless communications use the RF spectrum and broadcast by nature. Signals broadcast over airwaves can be easily intercepted with receivers tuned to the proper frequency. Thus, messages transmitted can be eavesdropped, and fake messages can be injected into network. Moreover, a radio signal can be jammed or interfered, which causes the message to be corrupted or lost. If the attacker has a powerful transmitter, a signal can be generated that will be strong enough to overwhelm the targeted signals and disrupt communications. The most common types of this form of signal jamming are random noise and pulse. Jamming equipment is readily available. In addition, jamming attacks can be mounted from a location remote to the target networks. B. Link layer attacks The MANET is an open multipoint peer-to-peer network architecture. Specifically, one-hop connectivity among neighbors is maintained by the link layer protocols and the network layer protocols extend the connectivity to other nodes in the network. Attacks may target the link layer by disrupting the cooperation of the layer s protocols. C. Network layer attacks Network layer protocols extend connectivity from neighboring 1-hops nodes to allothernodes in MANET. The connectivity between mobile hosts over a potentially multi-hop wireless link strongly relies on cooperative reactions among all network nodes. The traffic packets could be forwarded to a non-optimal path, which could introduce significant delay. In addition, the packets could be forwarded to a nonexistent path and get lost. The attackers can create routing loops, introduce severe network congestion, and channel contention into certain areas. Multiple colluding attackers may even prevent a source node from finding any route to the destination, causing the network to partition, which triggers excessive network control traffic, and further intensifies network congestion and performance degradation. D. Transport layer attacks The objectives of TCP-like Transport layer protocols in MANET include setting up of end-to-end connection, endto-end reliable delivery of packets, flow control, congestion control, clearing of end-to-end connection. Similar to TCP protocols in the Internet, the mobile node is vulnerable to the classic SYN flooding attack or session hijacking attacks. However, a MANET has a higher channel error rate when compared with wired networks. Because TCP does not have any mechanism to distinguish between whether a loss was caused by congestion, random error, or malicious attacks, TCP multiplicatively decreases its congestion window upon experiencing losses, which degrades network performance significantly. E. Application layer attacks Application layer attacks can be mobile viruses, worm attacks, and repudiation attacks. a) Mobile virus and worm attacks: The application layer contains user data, and it normally supports many protocols such as HTTP, SMTP, and FTP. Malicious code, which includes viruses and worms, is applicable across operating systems and applications. b) Repudiation attack: In the network layer, firewalls can be installed to keep packets in or keep packets out. In the transport layer, entire connections can be encrypted, end-to-end. But these solutions do not solve the authentication or non-repudiation problems in general. c) Multi-layer attacks: Some security attacks can be launched from multiple layers instead of a particular layer. Examples of multi-layer attacks are denial of service (DoS), man-in-the middle, and impersonation attacks VI. APPLICATIONS With the increase of portable devices as well as progress in wireless communication, ad-hoc networking is gaining importance with the increasing number of widespread applications. Ad-hoc networking can be applied anywhere where there is little or no communication infrastructure or the existing infrastructure is expensive or inconvenient to use. Ad hoc networking allows the devices to maintain connections to the network as well as easily adding and removing devices to and from the network. The set of applications for MANET is diverse, ranging from large-scale, mobile, highly dynamic networks, to small, static networks that are constrained by power sources. Besides the legacy applications that move from traditional infra structured environment into the ad hoc context, a great deal of new services can and will be generated for the new environment. Some of the typical applications include: A. Military Battlefield: Military equipment now routinely contains some sort of computer equipment. Ad- hoc networking would allow the military to take advantage of commonplace network technology to maintain an information network between the soldiers, vehicles, and military information headquarters. The basic techniques of ad hoc network came from this field. B. Commercial Sector: Ad hoc can be used in emergency/rescue operations for disaster relief efforts, e.g. in fire, flood, or earthquake. Emergency rescue operations must take place where nonexisting or damaged communications infrastructure and 579 International Journal of Computer Systems, ISSN-( ), Vol. 02, Issue 12, December, 2015

5 rapid deployment of a communication network is needed. Information is relayed from one rescue team member to another over a small hand held. Other commercial scenarios include e.g. ship-to-ship ad hoc mobile communication, law enforcement, etc. C. Local Level: Ad hoc networks can autonomously link an instant and temporary multimedia network using notebook computers or palmtop computers to spread and share information among participants at e.g. conference or classroom. Another appropriate local level application might be in home networks where devices can communicate directly to exchange information. Similarly in other civilian environments like taxicab, sports stadium, boat and small aircraft, mobile ad hoc communications will have many applications. D. Personal Area Network (PAN): Short-range MANET can simplify the intercommunication between various mobile devices (such as a PDA, a laptop, and a cellular phone). Tedious wired cables are replaced with wireless connections. Such an ad hoc network can also extend the access to the Internet or other networks by mechanisms e.g. Wireless LAN (WLAN), GPRS, and UMTS. The PAN is potentially a promising application field of MANET in the future pervasive computing context. E. MANET-VoVoN: A MANET enabled version of JXTA peer-to-peer, modular, open platform is used to support user location and audio streaming over the JXTA virtual overlay network. Using MANET-JXTA, a client can search asynchronously for a user and a call setup until a path is available to reach the user. The application uses a private signaling protocol based on the exchange of XML messages over MANET- JXTA communication channels. [6] Mohseni, S.; Hassan, R.; Patel, A.; Razali, R, Comparative review study of reactive and proactive routing protocols in MANETs, 4th IEEE International Conference on Digital Ecosystems and Technologies, , [7] Humayun Bakht, Survey of Routing Protocols for Mobile Ad-hoc Network, International Journal of Information and Communication Technology Research, , October [8] Mohit Kumar and Rashmi Mishra An Overview of MANET: History, Challenges and Applications, Indian Journal of Computer Science and Engineering (IJCSE), Vol. 3 No. 1 Feb-Mar [9] Kavita Taneja, R.B. Patel An Overview of Mobile Ad hoc Networks: Challenges and Future. [10] Vikaram Patalbasi, Sonali Mote Mobile Ad hoc Networks: Opportunities and Future. VII. CONCLUSION Due to dynamic topology, distributed operation and limited bandwidth MANET is more vulnerable to many attacks. Security attack can classified as an active or passive attacks. Different security mechanisms are introduced in order to prevent such network. MANET architecture and its characteristics are analyzed. The paper focused mainly on security issues of MANET. REFERENCES [1] Priyanka Goyal, Vinti Parmar and Rahul Rishi, MANET: Vulnerabilities, Challenges, Attacks, Application, IJCEM International Journal of Computational Engineering & Management, Vol. 11, January [2] Gagandeep, Aashima and Pawan Kumar Analysis of Different Security Attacks in MANETs on Protocol Stack. International Journal of Engineering and Advanced Technology (IJEAT), Volume-1, Issue-5, June [3] Sunil Taneja and Ashwani Kush, A Survey of Routing Protocols in Mobile Ad-Hoc Networks, International Journal of Innovation, Management and Technology, Vol. 1, No. 3, , August [4] Gary Breed Editorial Director, Wireless Ad-Hoc Networks: Basic Concepts, High Frequency Electronics, March [5] Hongmei Deng, Wei Li, and Dharma P. Agrawal, Routing Security in Wireless Ad Hoc Networks IEEE Communications Magazine October International Journal of Computer Systems, ISSN-( ), Vol. 02, Issue 12, December, 2015