MANET Casestudy2

7/29/2019 MANET Casestudy2

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ABSTRACT:

This case study presents a distributed sleep scheduling protocol and

security problem in ad hoc network. Distributed sleep scheduling protocol that

can be used for implementing synchronous interface sleep for energy

conservation in wireless Ad Hoc (MANETs Mobile Ad Hoc Network) networks.Central idea of this protocol is to distribute a common sleep-awake cycle

schedule among all nodes within a connected partition so that the nodes can turn

their interface off during the sleep section of the agreed upon schedule, and they

can communicate during the wake section of the schedule.

The main assumption of the ad hoc routing protocols is that all

anticipating nodes do so in good faith and without maliciously disrupting the

operation of the protocol. But, the existence of malicious entities cannot be

disregarded in any system, especially in open ones like ad hoc networks. In ad hoc

network the routing function can be disrupted by internal or external attackers.

INTRODUCTION:

History:

Ad hoc networks date back to the Seventies. They were developed by the

Defence Forces, to comply with a military framework. The aim was to rapidlydeploy a robust, mobile and reactive network, under any circumstances. These

networks then proved useful in commercial and industrial fields, first aid

operations and exploration missions.

WHAT IS AD HOC NETWORK?

A wireless ad-hoc network is a decentralized type ofwireless network. The

network is ad hoc because it does not rely on a pre-existing infrastructure, such

as routers in wired networks or access points in managed (infrastructure)wireless networks. Instead, each node participates in routing by forwarding data

for other nodes, and so the determination of which nodes forward data is made

dynamically based on the network connectivity.

An ad-hoc network is a self-configuring network of wireless links
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connecting mobile nodes. These nodes may be routers and/or hosts. The mobile

nodes communicate directly with each other and without the aid of access points,

and therefore have no fixed infrastructure. They form an arbitrary topology,

where the routers are free to move randomly and arrange themselves as required.

(i.e. .) MANET is a self-configuringinfrastructure less networkof mobile devices connected bywireless. Each device

in a MANET is free to move independently in any direction, and will therefore

change its links to other devices frequently. Each must forward traffic unrelated

to its own use, and therefore be a router.

In simple terms - Mobile ad hoc networks (MANETs) can be defined as a

collection of large number of mobile nodes that form temporary network without

aid of any existing network infrastructure or central access point. Each node

participating in the network acts both as host and a router and must therefore is

willing to forward to packets for other nodes. The characteristics of MANETs such

as: dynamic topology, node mobility, provides large number of degree of freedom

and self-organizing capability of that make it completely different from other

network. Due to the nature of MANETs, to design and development of secure

routing is challenging task for researcher in an open and distributed

communication environments.

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 MANETs is diverse, ranging from

large-scale, mobile, highly dynamic networks, to small, static networks that are

constrained by power sources.

Routing protocols between any pair of nodes within an ad hoc network can

be difficult because the nodes can move randomly and can also join or leave the
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network. Most MANET routing protocols are vulnerable to attacks that can freeze

the whole network. The main reasons for this difficulty are;

"Shared broadcast radio channel, insecure operating environment, lack of

central authority, lack of association among nodes, limited availability of

resources, and physical vulnerability."

The dynamic relationship between the nodes leaves very little opportunity

for the nodes to form trust relationships with each other. In an ad-hoc network,

nodes must act as both terminals and routers for other nodes. Because there are

no dedicated nodes, a secure routing protocol is needed.

Ad hoc networks, also called peer-to-peer networks, still have a long way to

go in order to be fully functional and commercial, as it has its defects such as

security and routing which we will discuss further.

Existing ad-hoc network routing protocols fall into:

Ad-hoc Mobile Routing Protocols

, also known as Proactive Protocols, work out

routes in the background independent of traffic demands. Each node uses routing


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information to store the location information of other nodes in the network and

this information is then used to move data among different nodes in the network.

This type of protocol is slow to converge and may be prone to routing loops.

These protocols keep a constant overview of the network and this can be a

disadvantage as they may react to change in the network topology even if notraffic is affected by the topology modification which could create unnecessary

overhead.

Even in a network with little data traffic, Table Driven Protocols will use

limited resources such as power and link bandwidth therefore they might not be

considered an effective routing solution for Ad-hoc Networks. Fisheye State

Routing is an example of a Table Driven Protocol.

, also known as Reactive Protocols, establish

routes between nodes only when they are required to route data packets. There is

no updating of every possible route in the network instead it focuses on routes

that are being used or being set up. When a route is required by a source node to

a destination for which it does not have route information, it starts a route

discovery process which goes from one node to the other until it arrives at the

destination or a node in-between has a route to the destination. On Demand

protocols are generally considered efficient when the route discovery is less

frequent than the data transfer because the network traffic caused by the route

discovery step is low compared to the total communication bandwidth. This

makes On Demand Protocols more suited to large networks with light traffic and

low mobility. An example of an On Demand Protocol is Dynamic Source Routing.

combine Table Based Routing Protocols with On

Demand Routing Protocols. They use distance-vectors for more precise metrics to

establish the best paths to destination networks, and report routing information

only when there is a change in the topology of the network.

Each node in the network has its own routing zone, the size of which is defined

by a zone radius, which is defined by a metric such as the number of hops. Each


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node keeps a record of routing information for its own zone. Zone Routing

Protocol (ZRP) is an example of a Hybrid routing protocol.

For energy conservation we come across Distributed Sleep-synchronization

Protocol. The aim of this protocol is to reduce energy consumption due to idle

listening.

A (MANET) is a group of mobile wireless nodes

which, upon deployment, cooperatively form an infrastructure-less network

without any centralized control and service infrastructure. Since MANET nodes

typically run from limited energy portable batteries, a critical design issue for

future wireless Ad-Hoc networks is the development of suitable communication

architectures, protocols and services that reduce power consumption, therebyincreasing the operational lifespan of network enabled wireless devices. Energy

conservation in a MANET node not only maximizes its own operational lifespan

but it can also help maximize the network lifespan and defer network

partitioning.

In addition to essential energy consumption due to transmissions and

receptions, there are three main sources of non-essential energy consumption.

The first source is overhearing where a node receives traffic not destined to it.The second source is collision. Collisions result in retransmissions and hence an

increase in energy expenditure. The third source, which we highlighted here, is

idle listening, which corresponds to energy consumption when a wireless

interface is in an idle state that is neither transmitting nor receiving.

Even in idle state an interface must be up and ready to receive possible

traffic. Interface hardwares, the power consumption during idle listening is quite

significant and is often comparable to the consumption rate during reception.

Protocol that reduces energy consumption due to idle listening by using a

distributed sleep-synchronization algorithm for maintaining a common

network-wide sleep schedule. Once synchronized, nodes can turn their interface

off during the sleep section of the synchronized schedule, and they can


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communicate during the wake section of the schedule. By turning the interface

off, the nodes can avoid energy consumption due to idle listening.

o Weaker in Securityo Device size limitationo Battery lifeo Dynamic topologyo Bandwidth and slower data transfer rate

Authentication

Integrity Confidentiality Non-Repudiation

Distributed Sleep-synchronization Protocol:

The aim of this protocol is to reduce energy consumption due to idle

listening. This is achieved by making use of a concept of periodic sleep and wake


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cycles that are synchronized across each neighbor pairs in the network. To

explain it further, any pair of neighbor nodes will maintain asynchronies sleep-

wake schedule so that their interfaces can sleep during the sleep period and they

can execute protocol for data transaction during the wake period. With this

mechanism, it is expected that during low loading situations the idle listeningconsumption will be significantly slashed by putting interfaces to sleep states that

typically has much lower power ratings.

The energy savings of this protocol depends on the wake-sleep duty cycle,

which can be defined as the wake duration normalized by the total cycle

duration. The wake-sleep duty cycle will also determine the sustainable loading

range, and it should be appropriately dimensioned based on the applications and

their loading requirements. Higher duty cycles can handle higher loads at thecost of lower idle energy savings.

The proposed distributed algorithm is implemented within a Sync Agent. A

Sync Agent runs in each node and it handles all sleep-synchronization related

functions including distributed schedule maintenance and instructing the

wireless interface hardware to sleep and wake up according to the converged

schedule.

An implicit assumption of our protocol is that all nodes within a networkare required to use the same wake-sleep cycle duration and duty cycle. The duty

cycle should be chosen depending on the network loading conditions and the

cycle duration should be dictated by the sleep-to-wakeup latency overhead of the

wireless interface card. We assume that the cycle duration and duty cycle

parameters are either manually configured or dynamically determined across the

network using an offline mechanism.


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The main assumption of the previously presented ad hoc routing protocols

is that all anticipating nodes do so in good faith and without maliciously

disrupting the operation of the protocol [19]. However, the existence of malicious

entities cannot be disregarded in any system, especially in open ones like ad hoc

networks. In ad hoc network the routing function can be disrupted by internal or

external attackers. An internal attacker can be any legitimate participant of the

routing protocol. An external attacker is defined as any other entity.

Cryptographic solutions can be employed to prevent the impact of external

attackers by mutual authentication of the participating nodes through digital

signature schemes. However, the underlying protocols should also be consideredsince an attacker could manipulate a lower level protocol to interrupt a security

mechanism in a higher level. Internal attackers having capability to complete

access the communication link they are able to advertise false routing

information at will and force arbitrary routing decisions on their peers.


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Security:

Authentication Confidentially Low power consumption Integrity Availability Non-repudiation

Generally, when considering the security of a network, we examine it

under the headings; availability, confidentiality, authentication, integrity and

non-repudiation. Availability refers to the fact that the network must remain

operational at all times despite denial of service attacks.

Confidentiality ensures that certain information is never disclosed to

certain users. Authentication is the ability of a node to identify the node

with which it is communicating. Integrity guarantees that a message is never

corrupted when transferred. Non-repudiation states that the sender of the

message cannot deny having sent it. An ad-hoc network has extra security

requirements caused by its lack of proper infrastructure and the dynamicrelationship between the nodes in the network.

Because of the lack of infrastructure, accountability is very difficult to

determine as there is - no central authority which can be referenced when it

comes to making trust decisions on other parties in the network."

Denial of Service Attacks


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Vulnerability:

The meaning of this vulnerability is self-evident: there is not such a clear

secure boundary in the mobile ad hoc network, which can be compared with the

clear line of defence in the traditional wired network.

This vulnerability originates from the nature of the mobile ad hoc network:

freedom to join, leave and move inside the network. Lack of secure boundaries

makes the mobile ad hoc network susceptible to the attacks. Due to this mobile ad

hoc network suffers from all-weather attacks, which can come from any node

that is in the radio range of any node in the network, at any time, and target to

any other node(s) in the network. To make matters worse, there are various link

attacks that can jeopardize the mobile ad hoc network, which make it even

harder for the nodes in the network to resist the attacks.

Current routing protocols are exposed to two types of attacks:


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Active attacks are the attacks that are performed by the malicious nodes

that bear some energy cost in order to perform the attacks. Active attacks involve

some modification of data stream or creation of false stream. E.g.: Spoofing,Fabrication, Wormhole Attack, Modification, Denial of Service, Sinkholes etc.

: Spoofing occurs when a malicious node misrepresents its identity in

order to alter the vision of the network topology that a benign node can gather.

: The notation fabrication is used when referring to attacks

performed by generating false routing messages. Such kind of attacks can be

difficult to identify as they come as valid routing constructs, especially in the case

of fabricated routing error messages, which claim that a neighbor can no longer

be contacted.

:An attacker records packets at one location in the network and

tunnels them to another location. Routing can be disrupted when routing controlmessages are tunneled. This tunnel between two colluding attackers is referred as

a wormhole. Wormhole attacks are severe threats to MANET routing protocols.

A B

Attacker

Assumed Route

Actual Route


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: The attacker performs such attacks is targeted to integrity of data,

by altering packet or modifying packets.

:In a sinkhole attack, a compromised node tries to attract the data to it

from all neighboring nodes. So, practically, the node eavesdrops on all the datathat is being communicated between its neighboring nodes.

In passive attacks the attacker does not perturb the routing protocol,

instead try to extract the valuable information like node hierarchy and network

topology from it. Passive attack is in nature of monitoring transmission. The goal

of opponent is to obtained information that is being transmitted. Passive attacksare very difficult to detect because they do not involve any alteration of data.

E.g.: Eavesdropping, traffic analysis, monitoring etc.

SECURE AD HOC ROUTING:

There exist several proposals that attempt to architect a secure routing

protocol for mobile ad hoc network, in order to offer protection against the

attacks. There are several solutions proposed by researcher they are either

completely new stand-alone protocol or in some cases incorporation of security

mechanism into existing one like DSDV and AODV. Cryptography is one of the

solutions for analysis of problem and protection of confidentiality of messages i.e.

Solution based on Symmetric cryptography, solution based on Asymmetric

cryptography and Hybrid solution.


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The future of ad hoc networks

Mobile ad hoc networks are the future of wireless networks. Why? Because

they're practical, versatile, simple, easy to use and inexpensive! We will be living

in a world where our network instantly updates and reconfigures itself to keep usconnected anywhere we go.

These networks provide a new approach for wireless communication and

by operating in a license free frequency band prove to be relatively inexpensive.

With the current trend of society's demand for information at our

fingertips, we will see our future living environments requiring communication

networks between the many devices we use in day to day living, allowing them to

talk to each other.For example devices like personal digital assistants and mobile phones

being able to receive instant messages from a home device. Such as a refrigerator

sending a message to a PDA to update its shopping list; notifying that it's run out

of milk. Or washing machines and ovens sending a report to say the clothes are

finished or the chickens cooked.

Likewise, in education ad hoc networks may be deployed for student

laptops interacting with the lecturer during classes. Also wireless public access

for dense urban areas (Nokia RoofTopT): A wireless broadband solution for

residential markets, based on a multi-hop Ad-Hoc (mesh) networking. [5] See

diagram below
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Nokia Roof Top Wireless Routing

WAND (Wireless Ad hoc Network for Dublin)

Closer to home, in Trinity College Dublin itself, the WAND venture,

Wireless Ad hoc Network for Dublin, is underway. WAND is a project that is

currently in progress to aid research in the area of ad-hoc networks. The project

is run by the Distributed Systems Group of Trinity College, in collaboration with

Media Lab Europe.

WAND is arranged as a large scale test bed for ad-hoc networks protocols

and applications, covering a 2km route from Trinity to Media Lab Europe. Seediagram below.

This route will be routed with custom-built wireless-enabled embedded

PCs. Along this stretch, the embedded PCs will be placed in apartments, shops, on

traffic lights and in phone booths providing a minimum level of connectivity.

The PCs form a sparse population of wireless network nodes. This sparse coverage

is constantly available and the embedded PCs can be configured to create a

variety of network models.Other devices with wireless connectivity may also connect to the network

via the implementation of mobile nodes.


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2km route from Trinity to MLE

Many factors lead us to believe that ad-hoc is the wireless network of the

future. Due to the network not requiring any base station makes them

indispensable in disaster relief situations or military war zones. Also energy issues

have moved us from using a single long wireless link (as in cellular) to a mesh of

short links (as in ad hoc networks). To sum up, ad-hoc networks will be the

future of our wireless networks.


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Conclusion:

After researching Ad-hoc networks in depth, we believe that they will be

the future of wireless networking. It is true that performance suffers as thenumber of devices grows and large ad-hoc networks become difficult to route

and manage. However, much time is being devoted to achieving routing stability,

and a few technical issues need to be solved before they become common place.

The area of ad hoc networks is a very fast growing area, and due to the vast

research in them, we are seeing these problems disappear and they are coming

into a world of their own.

MANET Casestudy2

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