This document discusses ad hoc networks and wireless sensor networks. It defines ad hoc networks as temporary networks composed of mobile nodes without preexisting communication infrastructure. It describes key characteristics of ad hoc networks including self-organization, multi-hop routing, and mobility. The document outlines several types of ad hoc networks and discusses important issues in designing routing protocols, medium access control, security, energy management, and more for ad hoc networks.

1. EC8702- AD HOC AND WIRELESS
SENSOR NETWORKS
Mr. M. Premkumar, AP/ECE
SSMIET
Mrs.THAHSEEN THAHIR, AP/ECE
JCTCET

2. Unit 1
AD HOC NETWORKS –
INTRODUCTION AND
ROUTING PROTOCOLS
Unit 1
AD HOC NETWORKS –
INTRODUCTION AND
ROUTING PROTOCOLS

3. AD HOC NETWORKS – INTRODUCTION
AND ROUTING PROTOCOLS
•Elements of Ad hoc Wireless Networks
•Issues in Ad hoc wireless networks
•Example commercial applications of Ad hoc networking
•Ad hoc wireless Internet
•Issues in Designing a Routing Protocol for Ad Hoc
Wireless Networks
•Classifications of Routing Protocols
•Table Driven Routing Protocols –(DSDV)
•On–Demand Routing protocols –(AODV)
•Elements of Ad hoc Wireless Networks
•Issues in Ad hoc wireless networks
•Example commercial applications of Ad hoc networking
•Ad hoc wireless Internet
•Issues in Designing a Routing Protocol for Ad Hoc
Wireless Networks
•Classifications of Routing Protocols
•Table Driven Routing Protocols –(DSDV)
•On–Demand Routing protocols –(AODV)

4. Types of Wireless Networks: infrastructure vs. ad-
hoc networks
infrastructure
network
AP
AP
AP
wired network
AP: Access Point
•Infrastructure
Networks
• Fixed, wired backbone
•Mobile communicates
directly with access
points
•Suitable for locations
where access points can
be placed
• Cellular networks
ad-hoc network
•Infrastructure
Networks
• Fixed, wired backbone
•Mobile communicates
directly with access
points
•Suitable for locations
where access points can
be placed
• Cellular networks

5. •BSS without an AP is called an ad hoc network
• BSS with an AP is called an infrastructure network

6. Multi Hop wireless networks

7. MHWNs

8. Ad Hoc Networks
• Temporary network composed of mobile nodes without preexisting
communication infrastructure, such as Access Point (AP) and Base
Station (BS).
• Each node plays the role of router for multi-hop routing.
• Self-organizing network without infrastructure networks
• Started from DARPA PRNet in 1970
• Cooperative nodes (wireless)
• Each node decode-and-forward packets for other nodes
• Multi-hop packet forwarding through wireless links
• Proactive/reactive/hybrid routing protocols
• Most works based on CSMA/CA to solve the interference problem
• Temporary network composed of mobile nodes without preexisting
communication infrastructure, such as Access Point (AP) and Base
Station (BS).
• Each node plays the role of router for multi-hop routing.
• Self-organizing network without infrastructure networks
• Started from DARPA PRNet in 1970
• Cooperative nodes (wireless)
• Each node decode-and-forward packets for other nodes
• Multi-hop packet forwarding through wireless links
• Proactive/reactive/hybrid routing protocols
• Most works based on CSMA/CA to solve the interference problem

9. Why Ad Hoc Networks ?
Ease of deployment
Speed of deployment
Decreased dependence on infrastructure
Ease of deployment
Speed of deployment
Decreased dependence on infrastructure

10. What is an Ad hoc Network?
A network without any base
stations “infrastructure-less”
or multi-hop
A collection of two or more
devices equipped with wireless
communications and networking
capability
Supports anytime and
anywhere computing
Two topologies:
Heterogeneous (left)
• Differences in capabilities
Homogeneous or fully
symmetric (Right)
• all nodes have identical
capabilities and
responsibilities
infrastructure
network
AP
AP
AP
wired network
AP: Access Point
communications and networking
capability
Supports anytime and
anywhere computing
Two topologies:
Heterogeneous (left)
• Differences in capabilities
Homogeneous or fully
symmetric (Right)
• all nodes have identical
capabilities and
responsibilities Homogeneous network
ad-hoc network
AP
AP wired network

11. Mobile Ad Hoc Networks?

12. Mobile Ad Hoc Networks?
Mobility causes route changes

13. What is an Ad hoc Network?
Self-organizing and adaptive –
Allows spontaneous formation
and deformation of mobile
networks
Each mobile host acts as a
router
Supports peer-to-peer
communications
Supports peer-to-remote
communications
Reduced administrative cost
Ease of deployment
infrastructure
network
AP
AP
AP
wired network
AP: Access Point
Self-organizing and adaptive –
Allows spontaneous formation
and deformation of mobile
networks
Each mobile host acts as a
router
Supports peer-to-peer
communications
Supports peer-to-remote
communications
Reduced administrative cost
Ease of deployment
ad-hoc network

14. Ad Hoc Networks – Operating
Principle
Example of an Ad Hoc Network
Fig. depicts a peer-to-peer multihop ad hoc network
Mobile node A communicates directly with B (single hop)
when a channel is available
If Channel is not available, then multi-hop communication is
necessary e.g. A->D->B
For multi-hop communication to work, the intermediate
nodes should route the packet i.e. they should act as a
router
Example: For communication between A-C, B, or D & E,
should act as routers
A
B C
D E
Example of an Ad Hoc Network
Fig. depicts a peer-to-peer multihop ad hoc network
Mobile node A communicates directly with B (single hop)
when a channel is available
If Channel is not available, then multi-hop communication is
necessary e.g. A->D->B
For multi-hop communication to work, the intermediate
nodes should route the packet i.e. they should act as a
router
Example: For communication between A-C, B, or D & E,
should act as routers

15. Bringing up an Ad hoc Network
1. Ad hoc network begins with at least two nodes broadcasting
their presence (beaconing) with their respective address
information
2. They may also include their location info if GPS equipped
3. Beaconing messages are control messages. If node A is able
to establish a direct communication with node B verified by
appropriate control messages between them, they both
update their routing tables
A
B C
D E
1. Ad hoc network begins with at least two nodes broadcasting
their presence (beaconing) with their respective address
information
2. They may also include their location info if GPS equipped
3. Beaconing messages are control messages. If node A is able
to establish a direct communication with node B verified by
appropriate control messages between them, they both
update their routing tables

16. Bringing up an Ad hoc Network
4. Third node C joins the network with its beacon
signal. Two scenarios are possible:
(i)A & B both try to determine if single hop
communication is feasible
(ii)Only one of the nodes e.g. B tries to
determine if single hop communication is feasible
and establishes a connection
A
B C
D E
4. Third node C joins the network with its beacon
signal. Two scenarios are possible:
(i)A & B both try to determine if single hop
communication is feasible
(ii)Only one of the nodes e.g. B tries to
determine if single hop communication is feasible
and establishes a connection

17. Bringing up an Ad hoc Network
5. The distinct topology updates consisting of both
address and the route updates are made in three
nodes immediately.
5. In first scenario, all routes are direct i.e. A->B,
B->C, and A->C (Lets assume bi-directional links)
A
B C
D E
5. The distinct topology updates consisting of both
address and the route updates are made in three
nodes immediately.
5. In first scenario, all routes are direct i.e. A->B,
B->C, and A->C (Lets assume bi-directional links)

18. Topology Update Due to a Link
Failure
Mobility of nodes may cause link breakage requiring route
updates
Assume link between B & C breaks because of some reason
Nodes A & C are still reachable via D and E
So old route between A &C was A->B->C is to be replaced by
A->D->E->C
All five nodes are required to incorporate this change in
their routing table
This change will happen first in nodes B & C
Then A & E
Then D
A
B
C
D E
Mobility of nodes may cause link breakage requiring route
updates
Assume link between B & C breaks because of some reason
Nodes A & C are still reachable via D and E
So old route between A &C was A->B->C is to be replaced by
A->D->E->C
All five nodes are required to incorporate this change in
their routing table
This change will happen first in nodes B & C
Then A & E
Then D

19. Types of Wireless Ad Hoc Networks
•Mobile ad hoc network (MANET)
An ad hoc network of mobile devices.
•Vehicular ad hoc network (VANET)
Used for communication between vehicles.
• Smartphone ad hoc network (SPAN)
Wireless ad hoc network created on smart phones via existing
technologies like Wi-Fi and Bluetooth.
• Wireless mesh network
A mesh network is an ad hoc network where the various nodes are in
communication directly with each other to relay information
throughout the total network.
•Mobile ad hoc network (MANET)
An ad hoc network of mobile devices.
•Vehicular ad hoc network (VANET)
Used for communication between vehicles.
• Smartphone ad hoc network (SPAN)
Wireless ad hoc network created on smart phones via existing
technologies like Wi-Fi and Bluetooth.
• Wireless mesh network
A mesh network is an ad hoc network where the various nodes are in
communication directly with each other to relay information
throughout the total network.

20. Types of Wireless Ad Hoc Networks
•Army tactical MENT
Used in the army for "on-the-move" communication
•Wireless sensor network
Wireless sensors that collect everything from
temperature and pressure readings to noise and humidity
levels
• Disaster rescue ad hoc network
Ad hoc networks are important when disaster strikes and
established communication hardware isn't functioning
properly.
•Army tactical MENT
Used in the army for "on-the-move" communication
•Wireless sensor network
Wireless sensors that collect everything from
temperature and pressure readings to noise and humidity
levels
• Disaster rescue ad hoc network
Ad hoc networks are important when disaster strikes and
established communication hardware isn't functioning
properly.

21. Advantages
•Ad-hoc networks can have more flexibility.
•It is better in mobility.
•It can be turn up and turn down in a very
short time.
•More economical
•It considered as a robust network because
of its non-hierarchical distributed control
and management mechanisms.
•Ad-hoc networks can have more flexibility.
•It is better in mobility.
•It can be turn up and turn down in a very
short time.
•More economical
•It considered as a robust network because
of its non-hierarchical distributed control
and management mechanisms.

22. Disadvantages
•Unpredictable Topology
•Limited Bandwidth
•Lose of data
•Interference
•Limited Security
• Energy Constraints
•Unpredictable Topology
•Limited Bandwidth
•Lose of data
•Interference
•Limited Security
• Energy Constraints

23. Issues in Ad hoc wireless networks
•Medium Access Control (MAC)
•Routing
•Multicasting
•Transport layer protocol
•Quality of Service (QOS)
•Self-organization
•Security
•Energy management
•Scalability
•Deployment considerations
•Medium Access Control (MAC)
•Routing
•Multicasting
•Transport layer protocol
•Quality of Service (QOS)
•Self-organization
•Security
•Energy management
•Scalability
•Deployment considerations

24. Medium Access Control
Major issues
•Distributed Operation
•Synchronization
•Hidden Terminals Problem
•Exposed Terminals Problem
•Throughput
•Minimizing the occurrence of collisions
•Maximizing channel utilization
•Minimizing control overhead
•Access delay
•Real-time Traffic support and Resource reservation
Major issues
•Distributed Operation
•Synchronization
•Hidden Terminals Problem
•Exposed Terminals Problem
•Throughput
•Minimizing the occurrence of collisions
•Maximizing channel utilization
•Minimizing control overhead
•Access delay
•Real-time Traffic support and Resource reservation

25. Hidden Terminals Problem

26. Exposed Terminals Problem

27. Routing
Major issues
•Mobility
•Bandwidth constraint
•Error-prone and shared channel
•Location-dependent contention
•Other resource constraints
•Computing power
•Battery power
•Buffer storage
Major issues
•Mobility
•Bandwidth constraint
•Error-prone and shared channel
•Location-dependent contention
•Other resource constraints
•Computing power
•Battery power
•Buffer storage

28. Multicasting
Major issues
•Robustness
•Efficiency
•Control overhead
•Quality of Service
•Efficient group management
•Scalability
•Security
Major issues
•Robustness
•Efficiency
•Control overhead
•Quality of Service
•Efficient group management
•Scalability
•Security

29. Transport Layer Protocol
The main objectives of the transport layer
protocols include :
•Setting up & maintaining end-to-end
connections
•Reliable end-to-end delivery of packets
•Flow control
•Congestion control.
The main objectives of the transport layer
protocols include :
•Setting up & maintaining end-to-end
connections
•Reliable end-to-end delivery of packets
•Flow control
•Congestion control.

30. Quality of Service (QoS)
•QoS is the performance level of services offered by a
service provider or a network to the user.
• QoS provisioning often requires
•Negotiation between host & the network
•Resource reservation schemes
•Priority scheduling
•Call admission control
•QoS parameters
•QoS is the performance level of services offered by a
service provider or a network to the user.
• QoS provisioning often requires
•Negotiation between host & the network
•Resource reservation schemes
•Priority scheduling
•Call admission control
•QoS parameters

31. QoS-aware routing
•Finding the path is the first step toward a QoS-aware
routing protocol.
•The parameters that can be considered for routing
decisions are
•Network throughput
•Packet delivery ratio
•Reliability
•Delay
•Delay jitter
•Packet loss rate
•Bit error rate
QoS-aware routing
•Finding the path is the first step toward a QoS-aware
routing protocol.
•The parameters that can be considered for routing
decisions are
•Network throughput
•Packet delivery ratio
•Reliability
•Delay
•Delay jitter
•Packet loss rate
•Bit error rate

32. Self-Organization
•One very important property that an ad hoc wireless
network should exhibit is organizing & maintaining the
network by itself.
•The major activities that an ad hoc wireless network is
required to perform for self organization are,
•Neighbor discovery.
•Topology organization &
•Topology reorganization (updating topology
information)
•One very important property that an ad hoc wireless
network should exhibit is organizing & maintaining the
network by itself.
•The major activities that an ad hoc wireless network is
required to perform for self organization are,
•Neighbor discovery.
•Topology organization &
•Topology reorganization (updating topology
information)

33. Security
•It is an important issue
•Attacks against network are two types
•Passive attack
•Active attack
•External attack
•Internal attack
•The major security threats are
•Denial of service
•Resource consumption
•Host impersonation
•Interference
•It is an important issue
•Attacks against network are two types
•Passive attack
•Active attack
•External attack
•Internal attack
•The major security threats are
•Denial of service
•Resource consumption
•Host impersonation
•Interference

34. Energy Management
•It is a process of managing the sources to enhance the
lifetime of a network.
• Features are
•Shaping the energy discharge pattern of a node’s battery
to enhance battery life
•Finding routes that consumes minimum energy
•Using distributed scheduling schemes to improve battery
life
•Handling the processor & interface devices to minimize
power consumption.
•It is a process of managing the sources to enhance the
lifetime of a network.
• Features are
•Shaping the energy discharge pattern of a node’s battery
to enhance battery life
•Finding routes that consumes minimum energy
•Using distributed scheduling schemes to improve battery
life
•Handling the processor & interface devices to minimize
power consumption.

35. Categories
•Transmission power management
•Battery energy management
•Processor power management
•Devices power management
Categories
•Transmission power management
•Battery energy management
•Processor power management
•Devices power management

36. Scalability
•Scalability is the ability of the routing
protocol to scale well in a network with a
large number of nodes.
• It requires minimization of control overhead
& adaptation of the routing protocol to the
network size.
•Scalability is the ability of the routing
protocol to scale well in a network with a
large number of nodes.
• It requires minimization of control overhead
& adaptation of the routing protocol to the
network size.

37. Deployment Considerations
•The deployment of a commercial ad hoc
wireless network has the following benefits
when compared to wired networks
•Low cost of deployment
•Incremental deployment
•Short deployment time
•Reconfigurability
•The deployment of a commercial ad hoc
wireless network has the following benefits
when compared to wired networks
•Low cost of deployment
•Incremental deployment
•Short deployment time
•Reconfigurability

38. Challenges in Ad hoc Mobile Networks
•Host is no longer an end system - can also be an
acting intermediate system
•Changing the network topology over time
•Potentially frequent network partitions
•Every node can be mobile
•Limited power capacity
•Limited wireless bandwidth
•Presence of varying channel quality
•Host is no longer an end system - can also be an
acting intermediate system
•Changing the network topology over time
•Potentially frequent network partitions
•Every node can be mobile
•Limited power capacity
•Limited wireless bandwidth
•Presence of varying channel quality

39. Challenges in Ad hoc Mobile Networks
•No centralized entity – distributed
•How to support routing?
•How to support channel access?
•How to deal with mobility?
•How to conserve power?
•How to use bandwidth efficiently?
•No centralized entity – distributed
•How to support routing?
•How to support channel access?
•How to deal with mobility?
•How to conserve power?
•How to use bandwidth efficiently?

40. AD HOC WIRELESS INTERNET
•It extends the services of the internet to the
end users over an adhoc wireless network.
•Some of the applications are
•Wireless mesh network
•Provisioning of temporary internet services to major
conference venues
•Sports venues
•Temporary military settlements
•Battlefields
•Broadband internet services in rural regions
•It extends the services of the internet to the
end users over an adhoc wireless network.
•Some of the applications are
•Wireless mesh network
•Provisioning of temporary internet services to major
conference venues
•Sports venues
•Temporary military settlements
•Battlefields
•Broadband internet services in rural regions

42. Gateway
•They are the entry points to the wired internet.
•Generally owned & operated by a service provider.
•They perform following tasks ,
•Keeping track of end users.
•Bandwidth management.
•Load balancing.
•Traffic shaping.
•Packet filtering.
•Width fairness &
•Address, service & location discovery.
•They are the entry points to the wired internet.
•Generally owned & operated by a service provider.
•They perform following tasks ,
•Keeping track of end users.
•Bandwidth management.
•Load balancing.
•Traffic shaping.
•Packet filtering.
•Width fairness &
•Address, service & location discovery.

43. Address mobility
•This problem is worse here as the nodes
operate over multiple wireless hops.
•Solution such as Mobile IP can provide
temporary alternative.
•This problem is worse here as the nodes
operate over multiple wireless hops.
•Solution such as Mobile IP can provide
temporary alternative.

44. Routing
• It is a major problem in ad hoc wireless
internet,
•due to dynamic topological changes
•the presence of gateways
•multi-hop relaying
•the hybrid character of the network
•Solution -> use separate routing protocol for
the wireless part of ad hoc wireless internet.
• It is a major problem in ad hoc wireless
internet,
•due to dynamic topological changes
•the presence of gateways
•multi-hop relaying
•the hybrid character of the network
•Solution -> use separate routing protocol for
the wireless part of ad hoc wireless internet.

45. Other issues
•Transport layer protocol
•Load balancing
•Pricing / Billing
•Provisioning of security
•QoS support
•Service, address & location discovery
•Transport layer protocol
•Load balancing
•Pricing / Billing
•Provisioning of security
•QoS support
•Service, address & location discovery

46. Ad hoc wireless Internet implemented by a
wireless mesh network

47. Problems Facing Routing in Ad hoc Networks
•Routers are now moving
•Link changes are happening quite often
Packet losses due to transmission errors
•Event updates are sent often – a lot of control
traffic
•Routing table may not be able to, converge
•Routing loop may exist
•Current wired routing uses shortest path
metric
•Routers are now moving
•Link changes are happening quite often
Packet losses due to transmission errors
•Event updates are sent often – a lot of control
traffic
•Routing table may not be able to, converge
•Routing loop may exist
•Current wired routing uses shortest path
metric

48. Problems facing channel access in Ad hoc
Networks
•Distributed channel access, i.e. no fixed
base station concept
•Very hard to avoid packet collisions
•Very hard to support QoS
•Early work on packet radio is based on
CSMA
•Distributed channel access, i.e. no fixed
base station concept
•Very hard to avoid packet collisions
•Very hard to support QoS
•Early work on packet radio is based on
CSMA

49. Problems of Mobility in Ad hoc
•Mobility affects signal transmission ->
Affects communication
•Mobility affects channel access
•Mobility affects routing
•Mobility-induced route changes
•Mobility-induced packet losses
•Mobility affects multicasting
•Mobility affects applications
•Mobility affects signal transmission ->
Affects communication
•Mobility affects channel access
•Mobility affects routing
•Mobility-induced route changes
•Mobility-induced packet losses
•Mobility affects multicasting
•Mobility affects applications

50. Mobility in Ad hoc Networks
•Mobility patterns may be different
•people sitting at an airport lounge
•New York taxi cabs
•kids playing
•military movements
•personal area network
•Mobility characteristics
•speed
•predictability
• direction of movement
• pattern of movement
•Mobility patterns may be different
•people sitting at an airport lounge
•New York taxi cabs
•kids playing
•military movements
•personal area network
•Mobility characteristics
•speed
•predictability
• direction of movement
• pattern of movement

51. Problems of Power in Ad hoc
•Ad hoc devices come in many different forms
•Most of them battery powered
•Battery technology is not progressing as fast as
memory or CPU technologies
•Wireless transmission, reception, retransmission,
beaconing, consume power!
•Quest for power-efficient protocols
•Quest for better power management techniques
•Ad hoc devices come in many different forms
•Most of them battery powered
•Battery technology is not progressing as fast as
memory or CPU technologies
•Wireless transmission, reception, retransmission,
beaconing, consume power!
•Quest for power-efficient protocols
•Quest for better power management techniques

52. Research on Mobile Ad Hoc
Networks
•Variations in capabilities & responsibilities
•Variations in traffic characteristics,
mobility models, etc.
•Performance criteria (e.g., optimize
throughput, reduce energy consumption)
•Increased research funding -> Significant
research activity
•Variations in capabilities & responsibilities
•Variations in traffic characteristics,
mobility models, etc.
•Performance criteria (e.g., optimize
throughput, reduce energy consumption)
•Increased research funding -> Significant
research activity

53. Classifications of routing
protocols

54. Table Driven Routing Protocols
•Extensions of the wired network routing protocols.
•Maintains the global topology information in the form of
tables at every node.
•Tables are updated frequently in order to maintain
consistent and accurate network state information.
•Examples
•Destination Sequenced Distance Vector Routing
Protocol (DSDV)
•Wireless Routing Protocol (WRP)
•Source-Tree Adaptive Routing Protocol (STAR)
•Cluster-head Gateway Switch Routing Protocol (CGSR)
•Extensions of the wired network routing protocols.
•Maintains the global topology information in the form of
tables at every node.
•Tables are updated frequently in order to maintain
consistent and accurate network state information.
•Examples
•Destination Sequenced Distance Vector Routing
Protocol (DSDV)
•Wireless Routing Protocol (WRP)
•Source-Tree Adaptive Routing Protocol (STAR)
•Cluster-head Gateway Switch Routing Protocol (CGSR)

55. Destination Sequenced Distance Vector Routing
Protocol (DSDV)
•It is a modified version of Bellman Ford Algorithm
•It is a hop-by-hop vector routing protocol requiring
each node to periodically broadcast routing updates.
•Each node maintains routing information for all known
destinations
•Routing information must be updated periodically
•Traffic overhead even if there is no change in network
topology
•Maintains routes which are never used
•Allows fast reaction to topology changes
•It is a modified version of Bellman Ford Algorithm
•It is a hop-by-hop vector routing protocol requiring
each node to periodically broadcast routing updates.
•Each node maintains routing information for all known
destinations
•Routing information must be updated periodically
•Traffic overhead even if there is no change in network
topology
•Maintains routes which are never used
•Allows fast reaction to topology changes

56. DSDV Table Format
Table updates
•Incremental updates-> single network
data packet unit(NDPU)
•Full dump updates-> multiple NDPUs

57. Route Establishment in DSDV

58. Route maintenance in DSDV

59. Advantages
•Less delay involved in the route setup process
•Mechanism of incremental update with
sequence number tags makes the existing wired
network protocols adaptable to ad hoc wireless
networks
•The updates are propagated throughout the
network in order to maintain an up-to-date
view of the network topology at all nodes.
•Less delay involved in the route setup process
•Mechanism of incremental update with
sequence number tags makes the existing wired
network protocols adaptable to ad hoc wireless
networks
•The updates are propagated throughout the
network in order to maintain an up-to-date
view of the network topology at all nodes.

60. Disadvantages
•Broken links lead to a heavy control overhead during high
mobility
•Even a small network with high mobility or a large
network with low mobility can completely choke the
available bandwidth
•Suffers from excessive control overhead
•In order to obtain information about a particular
destination node, a node has to wait for a table update
message initiated by the same destination node
•Broken links lead to a heavy control overhead during high
mobility
•Even a small network with high mobility or a large
network with low mobility can completely choke the
available bandwidth
•Suffers from excessive control overhead
•In order to obtain information about a particular
destination node, a node has to wait for a table update
message initiated by the same destination node

61. ON-DEMAND ROUTING PROTOCOLS
•In table-driven protocols, each node maintain up-to-
date routing information to all the
nodes in the network
•In on-demand protocols a node finds the route to
a destination when it desires to send packets to the
destination
•Ex
•Dynamic source routing protocol (DSR)
•Ad hoc on-demand distance-vector routing protocol
(AODV)
•In table-driven protocols, each node maintain up-to-
date routing information to all the
nodes in the network
•In on-demand protocols a node finds the route to
a destination when it desires to send packets to the
destination
•Ex
•Dynamic source routing protocol (DSR)
•Ad hoc on-demand distance-vector routing protocol
(AODV)

62. Ad hoc On–Demand Distance Vector
Routing (AODV)
•Reactive routing protocol which does not maintain
routes but build the routes as per requirements
•AODV is used to overcome the drawbacks of DSR
•DSR maintains route information which makes it
slow.
• If the network is large, it is difficult to hold
whole information of the routes
• In AODV, along with routing tables of every node, two
counters including Sequence Number (SEQ NO) and
broadcast ID are maintained
•Reactive routing protocol which does not maintain
routes but build the routes as per requirements
•AODV is used to overcome the drawbacks of DSR
•DSR maintains route information which makes it
slow.
• If the network is large, it is difficult to hold
whole information of the routes
• In AODV, along with routing tables of every node, two
counters including Sequence Number (SEQ NO) and
broadcast ID are maintained

63. AODV
•Route Request carries
•source identifier (SrcID)
•Destination identifier (DestID)
•Source sequence number (SrcSeqNum)
•Destination sequence number (DestSeqNum)
•Broadcast identifier (BcastID)
•Time to live (TTL)
•Route Reply
•Route Request carries
•source identifier (SrcID)
•Destination identifier (DestID)
•Source sequence number (SrcSeqNum)
•Destination sequence number (DestSeqNum)
•Broadcast identifier (BcastID)
•Time to live (TTL)
•Route Reply

64. Route establishment in AODV

65. Route Maintenance in AODV

66. Advantage
•The routes are established on demand
and destination sequence numbers are
used to find the latest route to the
destination. So the connection setup delay
is less
•Dynamic networks can be handled easily.
•No loop generation
•The routes are established on demand
and destination sequence numbers are
used to find the latest route to the
destination. So the connection setup delay
is less
•Dynamic networks can be handled easily.
•No loop generation

67. Disadvantage
•Multiple RouteReply packets in response
to a single RouteRequest packet can lead
to heavy control overhead
•Periodic beaconing leads to unnecessary
bandwidth consumption
•Multiple RouteReply packets in response
to a single RouteRequest packet can lead
to heavy control overhead
•Periodic beaconing leads to unnecessary
bandwidth consumption