TARUN VARSHNEYvarshney@live.in

Department of Information Technology

ABES Engineering College

MANET : The Art of Networking without a Network

Wireless Networks

• Computer network that is wireless

• Infrastructure-based networks

• Less expensive to setup

IP backbone

ServerRouter

Gateways

Disadvantages

• Disaster areas • no infrastructure

• Large construction sites• Too expensive• Inconvenient

• Military operations

Solution???

• Mobile ad hoc network

• Mobile ad hoc network (MANET), or simply ad hoc network, comprises nodes that freely and dynamically self-organize into arbitrary and temporary network topology without any infrastructure support.

Mobile

Random and perhaps changing

Ad Hoc

Not engineered i.e. made or happening only for a particular purpose or need, not planned before it happens

Network

Network, is a collection of systems and other hardware interconnected by communication channels that allow sharing of resources and information

MANET: Mobile Ad hoc Network

MANET is a self-configuring network of mobile nodes connected by wireless links - the union of which form an arbitrary topology.

Individual nodes act as routers

Minimal configuration and quick deployment make ad hoc networks suitable for emergency situations like natural or human-induced disasters, military conflicts, emergency medical situations etc.

Such a network may operate in a standalone fashion, or may be connected to the larger Internet.

MANET: Mobile Ad hoc Network (continued)

Mobile Ad Hoc Network (MANET) is a collection of two or more devices or nodes or terminals with wireless communication and networking capability that communicate with each other without the aid of any centralized administrator also the wireless nodes that can dynamically form a network to exchange information without using any existing fixed network infrastructure

MANET: Mobile Ad hoc Network (continued)

MANETs: Operation

A

BC

DE

F

InternetE

Gateway

Stand-alone MANETAfter one of the nodes is configured as a gateway, the entire network is

connected to an external network like Internet

Mobile Ad Network – HOME

A

B

C

MANET: Formation

MANET: Architecture

Collision – Hidden-Station Problem

• A wishes to communicate with B. However A cannot detect communication from C but can detect communication from B.

• C also wishes to communicate with B. Again C cannot detect communication from A but can detect Communication from B.

• C is hidden from A and A is hidden from C.

• Both A and C transmit and their signals collide leading to loss of both packets.

Collision – Exposed-station Problem

• Nodes A, B, and C can all detect communications from one another. However, Only C can detect communication from D.

• Node B wishes to send to Node A and Node C wishes to send to Node D.

• So Node B begins transmitting to Node A and Node C recognizes this. The medium is in use so Node C can not transmit to Node D.

• Even though both transmission requests could be made going in opposite directions, the transmission does not happen. This is because Node C is exposed to Nodes A and B while D is not.

Routing is the process of selecting paths in a network along which to send network traffic

Routing Protocols are the set of rules and regulation that are must followed during the communication over the network.

MANET: Routing and Routing Protocols

MANET: Classification of Routing Protocol

Proactive Routing Protocol or Table Driven Approaches:Maintain regular and up to date routing information about each node in the network by

propagating route updation at fixed time interval throughout the network.

Reactive Routing Protocol:Establish the route to a destination only when there is a demand for it.Also called as “Demand Protocol”.

Hybrid Routing Protocol:Combination of proactive and reactive protocolThe route is established with the proactive routes and uses reactive flooding for new

mobile nodes.

Reactive Routing ProtocolAd Hoc On-Demand Distance Vector (AODV)Dynamic Source Routing (DSR)Associativity Based Routing (ABR)

Proactive Routing ProtocolDestination-Sequenced Distance-Vector Routing (DSDV)Optimized Link State Routing (OLSR)The Wireless Routing Protocol (WRP)

MANET: Routing Protocols (continued)

Hybrid Routing ProtocolTemporary Ordered routing Algorithm (TORA)Zone Routing Protocol (ZPR)Order One routing Protocol(OOPR)

Constructs route on demand and reduce routing load. Uses table driven routing framework. Destination sequence number for routing packets to destination mobile nodes. Location independent algorithm. Bi-directional route.

Packet send from source to destination, floods the network with the RREQ packets. All mobile node receive RREQ from neighbor or update message then checks routing table to find out that if it is the destination node or if it has fresh route to the destination then unicast RREP which is routed back on a temporary reverse route generated by RREQ from source node or else it re-broadcast RREQ.

Ad Hoc On-Demand Distance Vector (AODV)

The Internet Engineering task Force MANET working group suggests two different types of matrices for Evaluting the performance of the protocols of the MANETs

Qualitative Metrics

Quantitative Metrics

Performance and Evaluation issues of Routing Protocols

Qualitative Metrics

Qualitative metrics include the :• Loop Freedom• On-Demand Routing Behavior• Proactive Behavior• Security• Unidirectional Link Support• Sleep Mode

Quantitative Metrics

Quantitative metrics broadly includes the:

• End-to-end data throughput and delay• Route Acquisition Time• Out-of-Order Delivery• Efficiency

Challenges in Securing MANETs

To secure an ad hoc network, the following attributes may be considered: - Availability- Confidentiality- Integrity- Authentication

Challenges in Securing MANETs

• Security exposures of ad hoc routing protocols are due to two different types of attacks:

- Active attacks through which the misbehaving node has to bear some energy costs in order to perform some harmful operation, and

- Passive attacks that mainly consist of lack of cooperation with the purpose of energy saving.

• Nodes that perform active attacks with the aim of damaging other nodes by causing network outage are considered to be malicious.

• Nodes that perform passive attacks with the aim of saving battery life for their own communications are considered to be selfish

• Selfish nodes can severely degrade network performances and eventually partition the network

Challenges in Securing MANETs

• In a wormhole attack a malicious node can record packets (or bits) at one location in the network and tunnel them to another location through a private network shared with a colluding malicious node.

• Most existing ad hoc routing protocols would be unable to find consistent routes to any destination

• When an attacker forwards only routing control messages and not data packets, communication may be severely damaged

Challenges in Securing MANETs- Wormhole Attacks

Initial Routing before attack

Challenges in Securing MANETs- Wormhole Attacks

Initial Routing before attack

Challenges in Securing MANETs- Wormhole Attacks

Tunnel packets received in one place of the network and replay them in another place

The attacker can have no key material. All it requires is two transceivers and one high quality out-of-band channel

Challenges in Securing MANETs- Wormhole Attacks

Most packets will be routed to the wormhole

The wormhole can drop packets or more subtly, selectively forward packets to avoid detection

MANET Applications

• Tactical Networks• Military communication, operation• Automated Battlefields

• Sensor Networks• Home applications: allow users to manage home device locally and

remotely

MANET Applications (continued)• Emergency Services• Replacement of a fixed infrastructure in case of

earthquake, hurricanes

• Home and Enterprise Networking• Shared whiteboard applications• Use PDA to print anywhere

• Entertainment• Multi-user games• Robotic pets

• MANETs is challenging and promising system concepts• Requires new type of architectures and protocols• Open areas• Secure routing protocol• Quality of service• Low power consumption

Conclusion

Conclusion

• Security of ad hoc networks has recently gained momentum in the research community• Due to the open nature of ad hoc networks and their inherent lack of

infrastructure, security exposures can be an impediment to basic network operation • Security solutions for MANET have to cope with a challenging

environment including scarce energy and computational resources and lack of persistent structure

• The solutions presented in this presentation only cover a subset of all threats and are far from providing a comprehensive answer to the security problem in ad hoc networks

• They often address isolated issues away from a global approach to security

• As the technology for ad hoc wireless networks gains maturity, comprehensive security solutions based on realistic trust models and addressing all prevalent issues like routing, key management and cooperation enforcement are expected to appear

Conclusion