Ad Hoc networks (for this purpose). ⢠Infrastructure-less : No fixed base stations. ⢠Nodes (each with transceiver) can communicate without external assistant.
A Survey on Ad Hoc Networks Prof. Dr. El-Sayed M. El-Rabaie Eng. Nancy A. Al-Shaer
Types of wireless networks • Infrastructure Networks • Base stations are the bridges • A mobile host communicates with the nearest base station • Hand over occurs when a mobile moves from one cell to another
Types of wireless networks contd. • Ad Hoc networks (for this purpose) • Infrastructure-less : No fixed base stations. • Nodes (each with transceiver) can communicate without external assistant. • Multi hop is needed to route information between nodes.
MANET versus Cellular networks contd.
Mobile Ad Hoc network versus cellular networks Mobile Ad Hoc Network
Cellular network
No fixed base stations, very rapid deployment
Fixed, pre-located cell sites and base stations
Highly dynamic network topologies Static backbone network topology with multi-hop Hostile environment (losses, noise) and Relatively benign environment and stable sporadic connectivity connectivity Automatic adaptation to changes
Detailed planning before base stations can be installed
Infrastructure-less networks
Infrastructure networks
Cost-effective
High setup costs
Less setup time
Large setup time
History of mobile Ad Hoc Networks • Earliest MANETs were called “packet radio” networks, sponsored by DARPA (1970) • These packet radio systems predated the Internet and were part of motivation of the original IP suite • Later DARPA experiments included the Survivable Radio Network (SURAN) project (1980s) • 1990s – the advent of inexpensive 802.11 radio cards for personal computer • Current MANETs are designed primary for military utility; examples include JTRS (Joint Tactical Radio System) and NTDR (Near-Term Digital Radio).
Types of Ad Hoc Networks • Mobile Ad Hoc Networks (MANETs) • Internet based MANET (IMANET). • Vehicular Ad Hoc Networks (VANET). • Intelligent Vehicular Ad Hoc Networks (InVANET).
• Quasi-static (hybrid) Ad Hoc networks • Wireless Sensor Networks (WSN) • Wireless Mesh Networks (WMN)
Types of Ad Hoc Networks contd. Wireless Sensor Networks
Wireless Mesh Networks
Important characteristics of MANET • Infrastructure-less: No need for pre-existing or fixed infrastructure. • Independent terminals: Each node can operate as a router and host. • Distributed (decentralized)operation: Network functions (routing, security)are divided among nodes. • Dynamic topology: Its topology changes randomly and frequently. Y X
X
Y
Important characteristics of MANET contd. • Multi hop routing: No default routes available, each node acts as a router. • Lightweight terminals: The MANET nodes are mobile devices with less CPU processing capability, small memory size, and low power storage. So, optimized algorithms for computing and communicating is required. • Energy-constrained operation: Batteries make electricity saving an issue. • Fluctuating link capacity: One end-to-end path can be shared by several sessions • Limited- bandwidth: Because of wireless links.
Applications of MANETs
• Military environments: • Soldiers, tanks, planes
• Civilian environments: • • • •
Taxi cab Meeting rooms Sports stadium Boats, small aircraft
• Personal Area Networks (PAN): • Cell phone, laptop, ear phone, wrist watches
• Emergency operations: • Search-and-rescue • Policing and fire fighting
MANET challenges • Conventional problems of wireless communications: • Limited transmission range • wireless medium impairments: interference, fading, external noise, signal att • Battery constraint (limited power)
• Additional problems due to special features (multi hop, dynamic topology, absence of fixed infrastructure): • • • •
Quality of Service Scalability Power control: running with batteries, little computing power. Routing: no infrastructure and dynamin topology with unpredictable and frequently changes.
• Security: new vulnerabilities, nasty neighbors, ease of snooping on wireless medium • Mobility: induced route changes and packet losses
MANET advantages • Rapid deployment with minimum number of users: • Because of self-organizing, self-administering, and self-creating capabilities.
• Well suited for unlicensed spectrum. • Provide access to services and information irrespective to the geographical area. • Suitable in situations where a fixed infrastructure is not trusted, not available, un reliable or too expensive. • Can work in a stand alone manner or integrate with the Internet. • Quickly connected and communicated. • Detailed planning of BSs installation or wiring is not required.
MANET advantages contd. • Decentralized network: • Easy adaptation to changes in network configuration.
• Scalability allows addition of more nodes. • Lower getting-started costs. • Can integrate with existing cellular networks.
Routing in Ad Hoc networks • Routing is a real issue in wireless Ad Hoc networks: • • • •
No infrastructure Dynamic topology Multi hop Destination node may stand outside the transmission range of a source node. So, each node must be able to act as a router.
• Routing depends on many factors: • • • • •
Selection of routers Network topology Request initiation Mobility and the increase in the number of moving nodes Specific underlying C\Cs as a guide in finding the path efficiently and quickly
Objectives of Routing Protocols • Establishment of the efficient and correct route between Source and destination.
• Correct packet delivery in the appropriate time.
Desired Prosperities of Routing Protocols • Considering bandwidth consumption and minimum overhead. N1 • A routing protocol should be distributed. • Assume routes as unidirectional links. • Power efficient • Considering security and reliability. • Supporting QoS requirements • Quick adaptation to changes in traffic pattern • Ease of implementation and simplicity • Hybrid protocols are preferred.
N3
N2
N4
N5
Classifications of Routing Protocols Routing Protocols for ad hoc networks
Proactive (Table-Driven)
Reactive (On-Demand)
Hybrid ZRP
DSDV
CBRP
GSR
DSR
FSR
AODV
WRP
TORA
CGSR
Three Main categories of Protocols 1. Table Driven Routing Protocols Proactive, learn the network’s topology before a forwarding request comes in
2. On-Demand Routing Protocols Reactive, become active only when needed
3. Hybrid Routing Protocols Compromise between Table driven and on-demand protocols
Proactive (Table Driven)Routing • Continuously evaluate the routes • Attempt to maintain consistent, up-to-date routing information • when a route is needed, one may be ready immediately • When the network topology changes • the protocol responds by propagating updates throughout the network to maintain a consistent view
• Examples DSDV, GSR, FSR, WRP, CGSR
Reactive (on-Demand)Routing • on-demand style: create routes only when it is desired by the source node • route discovery: invoke a route-determination procedure • the procedure is terminated when • a route has been found • no route is found after all route permutations are examined
• longer delay: sometimes a route may not be ready for use immediately when data packets come • Examples CBRP, DSR, AODV, TORA
Hybrid Routing • Combines the advantages of both proactive and reactive routing protocols • Examples ZRP
Comparison between Proactive and Reactive protocols Parameter Delay level Control traffic
Proactive Small as routes are predetermined Usually higher reactive
than
Reactive High as routes are computed on demand Increases with the mobility of active routes.
Periodic updates Route availability
Always required Always available
Handling mobility
Updates occur at regular Localized route intervals discovery is used
Scalability
Nearly
Storage requirement
Higher than reactive.
Communication overhead
High
Depends on the number of required routes. Low
Route structure
Flat/Hierarchical
Flat, except CBRP
Bandwidth requirement
High
Low
Power requirement
High
Low
up to 150 nodes.
Not required Computed on-demand
Higher than proactive.
Destination Sequenced Distance Vector Protocol (DSDV) • Based on Bellman-Ford Next Hop Routing (algorithm). • Each node maintains tables for : Next hop on path Listing all available destinations Distance (in hops) to destinations The attributes of each destination Sequence number ( keep current route) which is originated by the destination node
DSDV Draw Backs: • The main complexity in DSDV is in generating and maintaining these routing tables • Topology changes are slowly propagated • Count-to-infinity problem
• Moving nodes create confusion: • They carry connectivity data which are wrong at new place
• Table exchange eats bandwidth
Global State Routing (GSR) • Almost the same as DSDV • It employs the idea of link-state routing • The improvement is that, it can avoid the flooding of routing messages • Each node preserve four tables • Distance Table • Neighbor List • Topology Table • Next Hop Table • As in the link-state protocols, the routing messages are generated in accordance with a link change. • Advantage: the control over head is greatly reduced by using rout cache • Disadvantage: large size of packet header which increases with route length due to source routing
Fisheye State Routing (FSR) • It is a refinement of GSR. • Avoid the problem of BW wasting of GSR. • Update message will not include information about all messages • Instead, closer nodes’ information is more frequently exchanged than farther nodes’ information. So, the size of the update message is reduced. • The rule is that the accuracy and details of neighbor’s information are inversely proportional to its distance from the node itself. • Advantages: Reliable packet delivery • Disadvantage:
Cluster Head Gateway Switch Routing (CGSR) •
Uses DSDV as an underlying protocol and Least Cluster Change (LCC) clustering algorithm to select cluster heads and minimize routing changes. A cluster head is able to control a group of ad-hoc hosts Each node maintains two tables:
• •
1. 2.
•
A cluster member table, containing the cluster head for each destination node A DV-routing table, containing the next hop to the destination
The routing principle: • • • •
Lookup of the cluster head of the destination node Lookup of next hop Packet send to destination Destination cluster head delivers packet
• •
too frequent cluster head selection (with high mobility) introduces large overhead. Increased battery drains at cluster head
• Drawbacks:
•
Advantages:
• •
Better BW utilization Easy to implement priority scheduling scheme.
Cluster Head Gateway Switch Routing (CGSR) contd. 6 12
5
4 2
11
7
10
8
1
9 Gateway node
3
Cluster head Internal node
The Wireless Routing Protocol (WRP) • Table-based protocol with the goal of maintaining routing information among all nodes in the network • Each node is responsible for four tables: • • • •
Distance table Routing table Link-cost table Message retransmission list (MRL) table
• Link exchanges are propagated using update messages sent between neighboring nodes • Hello messages are periodically exchanged between neighbors • This protocol avoids count-to-infinity problem by forcing each node to check predecessor information • Drawbacks: four tables requires a large amount of memory and periodic hello message consumes power and bandwidth • Advantages: route setup process is very fast
Comparison Between Proactive Protocols Proactive Routing selection
DSDV Link state
FSR Shortest path
WRP Shortest path
CGSR Shortest path
Method
Broadcast
Broadcast
Broadcast
Broadcast
Route computation
Distributed
Distributed
Distributed
Distributed
Route support
Single
Single /Multiple Single
Single /Multiple
Topology structure
Flat
Hierarchal
Flat
Hierarchal
Critical nodes
None
None
None
Cluster-head
Updates repetition
Periodic and needed
Periodic
Periodic
Loop-free
Yes
Yes, but not instantaneous
Yes
Periodic and when local
Yes
Ad-Hoc On-Demand Distance Vector Routing (AODV) • Builds on DSDV algorithm and the improvement is on minimizing the number of required broadcasts by creating routes on an on-demand basis (not maintaining a complete list of routes) • Broadcast is used for route request • Advantages: • Use bandwidth efficiently
• Responsive to changes in topology • Scalable and ensures loop free routing
• Drawbacks: • Nodes use the routing caches to reply to route queries. • Result: “uncontrolled” replies • And repetitive updates in hosts’ caches yet early queries cannot stop the propagation of all query messages which are flooded all over the network
Dynamic Source Routing (DSR) • Based on the concept of source routing • Mobile nodes are required to maintain route caches that contain the source routes of which the mobile is aware • Two major phases: • Route discovery – uses route request and route reply packets • Route maintenance – uses route error packets and acknowledgments
• Advantages: No periodic hello message and fast recovery - cache can store multiple paths to a destination • Drawbacks: • The packets may be forwarded along stale cached routes. • It has a major scalability problem due to the nature of source routing. • Same as AODV, nodes use the routing caches to reply to route queries
Temporally-Ordered Routing Algorithm (TORA) • Highly adaptive, loop-free, distributed routing algorithm based on the concept of link reversal • Proposed to operate in a highly dynamic mobile networking environment • It is source initiated and provides multiple routes for any desired source/ destination pair • This algorithm requires synchronized clocks
Temporally-Ordered Routing Algorithm (TORA) contd. • Three basic functions: • Route creation • Route maintenance • Route erasure
• Advantages: • provides loop free paths at all instants and multiple routes so that if one
path is not available, other is readily available. • It establishes routes quickly so that they may be used before the topology changes.
• Drawbacks: • exhibits instability behavior similar to "count-to-infinity" problem in distance vector routing protocols.
Cluster Based Routing Protocol (CBRP) • Design Objective: A distributed, efficient, scalable protocol
• Major design decisions: • use clustering approach to minimize on-demand route discovery traffic • use “local repair” to reduce route acquisition delay and new route discovery traffic
• Advantages: • Reduced connection setup delay
• Disadvantages: • Large overhead control
Comparison Between Reactive Protocols Reactive Route maintained in
CBRP Cluster-head route table
DSR Route cache
Route reconfiguration
Remove path and Erase route and local path repair notify source
AODV Route
table
Erase route
and
notify source
TORA Route
Link reversal and route repair
Routing selection
First available path
Shortest and
up-
Shortest and
dated path
dated path
table
Shortest path up-
Route support
Multiple
Multiple
Single
Multiple
Topology structure
Hierarchal
Flat
Flat
Flat
Casting property
Broadcast
Unicast
Unicast
Broadcast
Overall complexity
Medium
Medium
Medium
Loop-free
Yes
Yes
Yes
No
Need of Hybrid Routing Protocols Proactive routing • Because of fast node mobility • The routes are frequently updated • However, most of the routing information is never used • So, the scarce bandwidth is wasted.
Reactive routing • Routes are established on demand • The bandwidth is efficiently utilized • Less suitable for real-time traffic due to: • long route request delays • And significant control traffic resulting from global flooding
Zone Routing Protocol (ZRP) • A hybrid example of proactive and reactive routing protocol is zone routing protocol . • It combines the best features of both. • Intra-zone Routing Protocol (IARP) utilizes proactive discovery within a nod e's local neighborhood. • Inter-zone Routing Protocol (IERP) utilizes reactive routing for communication between these neighborhoods. • ZRP divides the network into different zones. • The zone is defined as the node's local neighborhood. • Zone size is not fixed • The zone is determined in hops not by geographical measurement. • The zone radius expressed in hops is 2. • Each node may be within multiple overlapping zones • Because the zones overlap, ZRP can be classified as a flat protocol not hierarchical. • Network congestion can be reduced and optimal routes can be detected.
I A J B M
F
D K C H
E G
Comparison Between Proactive, Reactive and Hybrid Protocols Proactive
Reactive
Hybrid
Routing protocols
DSDV, GSR, FSR, WRP, CBRP, DSR, AODV, CGSR TORA
ZRP
Control overhead
High
Low
Medium
Route acquisition delay
Higher
Lower
Lower for intrazone, Higher for inter-zone
Bandwidth requirement
High
Low
Medium
Power requirement
High
Low
Medium
Security in Mobile Ad Hoc Networks • MANETs have larger security problems than conventional wired and wireless networks due to: • Dynamic topology • Absence of infrastructure
• The present security solutions of conventional networks cannot be directly applied to wireless MANET. • New security challenges have to be considered in the design of MANETs • Security aspects that must be well known when dealing with security challenges.
MANET Security Aspects
Security Requirements
Security Threats
Availability
misbehavior
Authenticity
Attacks
Confidentiality
Integrity
No-repudiation
Security Requirements of MANET • Availability: • Availability indicates that even though there is a latent problem in the system the required services are available in a timely manner.
• Authenticity: • This network service has the responsibility of determining the identity of each user. • Without an authentication mechanism, the competitor could impersonate a precious node and thus get access to private sources, or disturb the network by propagating some false messages.
• Confidentiality: • Confidentiality ensures that the specific data in the network can be accessed only by authorized users. • To satisfy confidentiality the specific data has to be kept in privacy from all participants that do not have the permission to access it.
Security Requirements of MANET contd. • Data Integrity: • Integrity guarantees that the data forwarded between nodes has not been altered during its transmission by pledging the data identity. • Information may be changed both accidentally or intentionally. • According to this service, only authorized users can edit, create or delete data.
• No-repudiation: • It makes sure that the data founder (source or destination) cannot disavow having sent or received such data. • This will help in isolating or detecting compromised nodes in the network.
MANETs Security Threats • misbehavior It results from a forbidden behavior of an internal node. The node does not intend to launch an attack. But, the node may aim to have an unfair advantage compared with the other nodes. That can cause unintentionally a damage to other nodes
• Attacks A secure system can be achieved via detecting attacks or preventing them and presenting a mechanism that can recover the attacks. Attacks can be defined as any action that purposely intent to cause any network damage.
Categories of Security Attacks in MANETs MANET Security Attacks
Based on Attack origin
Based on Attack nature
Internal
Active
External
Passive
Classification of MANET security attacks in various layers Layers Physical
Attack Type Eavesdropping Jamming Active interferences
Data link
Selfish misbehavior of nodes Malicious behavior of nodes Traffic analysis
Network
Black hole attack Wormhole attack Rushing attack
Transport
Session hijacking
SYN flooding attack Applicatio n
Malicious code attack Repudiation attack
Mode of Attack
Result of Attack
By receiver tuning to proper frequency By malicious node with known communication frequency Blocks the communication channel Selfish nodes
Reading messages by unintended receiver Prevents reception of legitimate packets Change order of messages
Drops the packets
Disrupts operation of routing Misdirects traffic protocol Topology information Information to unintended receiver Fake optimum route message Loss of confidential information on packets Tunnel between malicious Loss of safe route nodes Subvert route discovery Loss of safe route process Spoofs victim node IP address DoS attack
Open TCP connection with DoS attack victim node Viruses worms Attack to OS Denial of participation in parts Communication failure of communication
Security Attacks and Mitigation Techniques Security Attack
Black-hole Attack
Attack Type (Function)
Routing Protocol employed
Mitigation Techniques
No Packet The intruder drops DSR, forwarding all the packets AODV, forwarded to it in SAR, OLSR this attack
1- A path-based approach is used to detect and mitigate the attack. 2-Creditable routing table is employed detect the black holes and eliminate them.
Man-in-themiddle attack
The attacker records the packets at one side of the network and forward it to another side.
Any Ad Hoc routing protocol
1-Implementing digital signature to detect and prevent the attack. 2-A cooperative approach is used among the nodes to detect and minify the attack.
Disturbing Communicatio n
Malicious node pulls all network traffic towards itself and can fabricate or modify the packets.
Any Ad Hoc routing protocol
1-Trust based algorithm is used to minimize sink-hole attack. 2-Mobile agents are used in a technique to detect and reduce the attack.
Wormhole Attack
Sink-hole Attack
Brief Description of the Attack
Security Attacks and Mitigation Techniques contd. Security Attack
Grey-hole attack
Flooding attack
Route Fabrication
Spoofing
Packet dropping
Attack Type (Function)
Brief Description of the Attack
Selectively drops The attacker drops packets part of the data and cheats the previous node. Reduce system The intruder floods the efficiency network with faked traffic to damage the efficient functionality and the smooth of the network.
Routing Protocol employed
Mitigation Techniques
Detection mechanism involves proactively invoking of collaborative and distributive algorithm involving neighbors. Any Ad Hoc 1-Delaying the RREP from target routing to source to reduce the number protocol of messages sent in the network and so the flooding is controlled. 2-A capability based messages are forwarded by each node to preserve the global view of throughput and hence failing the attack. False data The malicious node AODV Fuzzy logic soft computing Insertion sent wrong routing method is used to create a messages into the quantifiable trust value among network. the network nodes. Impersonating The attacker assumes Any Ad Hoc To use secure public key other nodes’ the identity of another routing authentication which is based on identity node in the network. protocol the trust model. Dropping packets
AODV
of Selfish nodes drop all DSR, AODV the packets that they received.
Point Detection Algorithm (PDA) is employed.
Ad Hoc network Simulation Software • As a variety of MANET simulators are available • The choice of the suitable simulation platform that satisfies the researcher requirements and helps in performing necessary tests is vital NS-3
OMNET++
NS-2 GLOMOSIM
SIMULATORS
NCTUNs J-SIM
SWAN OPNET QUALNET
Comparison of Ad Hoc network Simulators Simulator License Type Language GUI Simulation Technique Documentation Support Scalability Ease of Use Emulation Support
Available Modules
Parallelism
Supported Operating System
OS-2
OS-3
Open Source Open Source
OMNET++
GLOMOSIM
Open Source C++, NED
Open Source
Yes Discrete Event Medium
Limited Discrete Event Poor
Yes Discrete Event Good
Large Easy Limited Support Wired, Wireless, Ad Hoc networks
Large Hard No
Medium Hard Yes
Wired, Wireless, Ad Hoc networks
Wired, Wireless, Ad Hoc networks
SMP/Beowulf
No
C++, OTCL
C++, Python
Limited Discrete Event Excellent
Limited Discrete Event
Small Hard Limited Support Wired, Wireless, Sensor, Ad Hoc networks No
Large Hard Yes
No
MPI/PVM
GNU/Linux, FreeBSD, Mac OS X, Windows XP, Windows Vista, Win.7
GNU/Linux, FreeBSD, Mac OS X, Windows XP, Windows Vista, Win.7
Windows XP Windows, or later, Linux, Sun Linux, Mac SPARC Solaris OS X
Excellent
IP, Non-IP based networks
NCTUNs
C
Open Source C
Free BSD, Fedora, Red hat, Ubuntu, Debian
Comparison Between Available Simulators • NS-3 is the fastest simulator among the mentioned simulators. While NS-3, OMNET++, and GloMoSim are recommended to carry out largescale network simulations. • NS-2 supports all range of protocols in all layers. It also facilitates the specific MANET routing protocols. • Hierarchical modeling and the powerful GUI are supported by OMNET++. • So, NS-2 and OMNET++ are the best choices for MANETs. • GloMoSim is a good and strong scalability power simulation tool. So, it will be useful to use with the wireless networks containing a large number of nodes
Future Scope • The integration of Ad Hoc networks with fixed infrastructure and other wireless networks which expected to be an essential part of the progress towards fourth generation communication networks. Technologically, the realization of this scope requires a large number of challenges related to protocols, services, and devices. • The design of Ad Hoc networks that can possess the advantage of the properties of new hardware technologies is an emerging challenge. For example, the utilization of smart (beamforming) antennas will require new medium access and neighbor discovery protocols. • Progress in hop-by-hop TCP is necessary to minimize end-to-end packet delivery time while minimizing the number of retransmission, maintaining reasonable bandwidth utilization, and decreasing network congestion occurrence.
Future Scope contd. • Innovations at the higher levels are required to provide the ability to dynamically alter modulation schemes, spread spectrum codes, and waveforms. • The MAC layer has to treat with exposed and hidden terminals, decrease packet collision rate and permit fair channel access. • At the network layer devices need to collaborate to calculate the routes. • The transport layer has to be able to deal with packet delay and loss properties which completely differ from wired networks. • Application layer must be capable of handling possible reconnections and disconnections. • All network protocol improvements have to consider possible security problems and integrate gradually with traditional networks
• Mobility and wireless nature of Ad Hoc network bring new security challenges to the design of the network. • One challenge is the difficulty to implement centralized security control due to infrastructureless and distributed nature of the Ad Hoc network. • The network needs to depend on singular security solution from each node which requires designers’ efforts. • Another challenge is that in MANETs an attack may come from different layers and from any direction. • There are many kinds of attack. So, it is necessary to understand the possible form of attack to develop successful security solution. • Due to the decentralized nature of the Ad Hoc network, authentication and encryption are challengeable.
Future Scope contd. • Another challenge is to extend the peer-to-peer Ad Hoc network to the Internet. This may be achieved by using a peer that establish a link to the Internet over a 3G service provider or via a wireless LAN access point. • In order to support multimedia services, an adaptive QoS must be implemented over the traditional resource reservation. • Ad Hoc routing protocols must satisfy the requirements of QoS to provide high throughput, more energy efficiency, lower end-to-end delay, and reduced routing overhead. • Improving an energy-aware routing protocol is important to maximize the life of batteries of small, light-weight mobile nodes that depend on portable batteries. • Due to continuous change of network topology, packet routing between any pair of nodes becomes a great challenge. • The design of distributed network functions is another challenge which related to the service availability problems. It could be investigated whether and which services or their locations could be circulated or shared among nodes
Conclusion • Ad-Hoc networks are the reliable solution in case of natural disasters, wars, or financial shortage. • The included history of Ad-Hoc networks confirmed the importance of such networks due to which many valuable research projects since 1972 have made a lot of efforts to study and develop Ad-Hoc networks. • The main characteristics of Ad-Hoc networks are • • • •
No infrastructure Network dynamic topology Easy and quick setup hop-by-hop communications.
• These characteristics have imposed a number of challenges • • • • •
Routing Security Quality of Service Reliability Power Consumption
• The challenges of Ad-Hoc networks necessitate a large amount of research and development in the incoming years
Conclusion contd. • The Ad-Hoc advantages mentioned in the survey make it sure that Ad-Hoc networks have become an essential part of today’s communication systems. • Because of the unique features and advantages of Ad-Hoc networks, they can provide some special applications. Such as military battlefield and disaster management. • As routing is one of the most critical and important challenges, the working principles and various types of proactive and reactive routing protocols are discussed and compared in a compact form. Which make it easier for the network designer to select the suitable routing protocol. • The development of ZRP hybrid routing protocol provides a compromise between proactive and reactive routing protocols.
Conclusion contd.
• Dynamic topology distributed operation, and infrastructure-less nature of the Ad Hoc network bring new security challenges to the design of the network. • There are many kinds of attacks and it is necessary to understand the possible forms of attack to develop successful security solutions. • This survey discussed briefly the security aspects that must be well known when dealing with security challenges. • Also, security threats in terms of misbehaviors and attack types are mentioned. • And a summary of the most popular security attacks and the proposed techniques to mitigate them is introduced
• A comparison of MANET simulators is introduced which can help researchers to choose the appropriate software that satisfies the network requirements in shorter time. • Finally, a spot is focused on the future scopes. Such as securing the Ad-Hoc network against malicious nodes and behaviors. And, providing mechanisms to reduce processing time and packet overhead of the routing protocols.
Thank you Any questions??
