Computer networks comparison of aodv and olsr in ad hoc networks

COPMUTER NETWORKS
Group Members:
 Asadullah Ilyas – 396
 Zain Ul Islam – 407
 Fazeel Ashraf – 398
 Ali Haider – 392

AODV AND OLSR ROUTING PROTOCOLS

 Key Terms
 Ad hoc Network: Infra Structure less networks

 AODV: Ad hoc On Demand Distance Vector

 OLSR: Optimized Link State Routing

 Wireless Ad hoc is Dynamically forming a temporary
network

1: COMPARING AODV AND OLSR
ROUTING PROTOCOLS
 By: Aleksandr Huhtonen (Helsinki University of
Technology)
 Abstract

 Mobile networks creates underlying architecture for
communication without the help of fixed routers

 Hosts have limited transmission range

 No fixed router

 Each host act as a router

PROBLEM

 Challenge for mobile protocols is that they also
have to deal with mobility of hosts. Hosts can
appear and disappear in various locations.

AD HOC NETWORK ROUTING PROTOCOLS

 Ad hoc network routing protocols
 Table Driven (Pro-Active): OLSR and Better
Approach To Mobile Ad hoc Networking
(B.A.T.M.A.N)

 On Demand (Reactive): AODV, Admission Control
Enabled On Demand Routing (ACOR), Dynamic
Source Routing and Dynamic Man-NET on Demand
Routing

QUALITIES TO BE EFFECTIVE

 Distributed Operation

 Loop freedom

 Demand based operation

 Proactive operation

 Security

 Sleep period operation

AD HOC ON DEMAND PROTOCOL (AODV)
 AODV is a Reactive protocol n Routes are created
when needed
 Routing table stores information about next hop
2 destination
 Route Discovery
 RREQ message with destination IP and Seq. # is
broadcasted
 Sequence number prevent looping
 RREP from desired destination is unicasted
 RREP-ACK optional
 RERR in case of route breakage
 Route repairing

AODV ROUTING TABLE

 Destination address

 Destination sequence number

 Hop count

 Next hop

 Route state (valid, in valid)

 Precursor list

ADVANTAGES
 Doesn’t need any central administrative system
to handle the routing system
 Reduce the control traffic messages

 The AODV has great advantage in overhead over
simple protocols.
 Using the RRER message AODV reacts relatively
quickly to the topological changes in the network
and updating affected host
 AODV is a loop free protocol

OPTIMIZED LINK STATE ROUTING (OLSR)
 OLSR is a proactive protocol, Routes are always
available
 Information of the network

 Topological change causes flooding

 Control Messages
 Hello Messages (one hop count)
 Topology Control Messages (TC)  topology info.
 Multipoint Relays (MPR)
 Neighbor Sensing by Hello Messages

 MPR Selector Set

 MPR can only transmit topology information

MPR (MULTI-POINT RELAYS)

 The core optimization in OLSR is that of MPR.
 It’s used to reduce the message exchange
overhead by reducing the number of hosts that
broadcast messages in a network.
 For efficiency MPR is kept low n only MPR can
send throughout messages.

ROUTING TABLE CALCULATION
 The host maintains the routing table
 The routing table entries have following
information:
i. destination address
ii. next address,
iii. number of hops to the destination

iv. local interface address.
The routing table is recalculated if any change
occurs in these sets.
 For the routes for routing table entry the
shortest path algorithm is used.

ADVANTAGES
 OLSR doesn’t need any infrastructure
 The proactive protocol provides that the protocol
has all the information to all the participated
hosts.
 Flooding is minimized by the MPRs having the
drawback of maximum usage of bandwidth
 OLSR is best for the networks using larger
number of nodes.

AODV AND OLSR ROUTING PROTOCOLS
FOR WIRELESS AD-HOC AND MESH
NETWORKSANALYSIS & RESULTS
End to end delay

For 100 nodes
For 50 nodes

THROUGHPUT

For 50 nodes 100 nodes

IMPLEMENTATION AND PERFORMANCES OF
AODV AND OLSR
 Writers
 A. Saika
 M.M.Himmi

 Abstract
 Comparing a reactive and proactive protocol
 Network Simulator 2 was used
 Concluded that it depends on several constraints

EXPERIMENT AND RESULTS
 There were 4 nodes, two fixed and two mobile.
 Measuring area was set to 500 x 500 m2

 Time of simulation was 150 seconds

 Protocols used were:
 AODV (for reactive)
 OLSR (for proactive)

 The result of network was a .tr file, used for
creating graphs and charts

A COMPARATIVE STUDY OF AODV
AND OLSR ON THE ORBIT TEST BED
 ORBIT stands for Open Access Research Test bed
 It is an indoor grid based wireless network
emulator consisting of 400 radio nodes.
 It is a test bed to conduct network based
experiments under conditions that are similar to
real life conditions.

EXPERIMENTAL SETUP
 Orbit Traffic Generator(OTG) and Orbit Traffic
Receiver(OTR) was used to generate TCP and
UDP traffic.
 20 nodes were created in the experiment. The
input load was gradually increased and
conducted the experiment for 100 s at each
setting to obtain steady.
 For each channel rate offered load was increased
until saturation.

RESULTS AND CONCLUSION
 After saturation OLSR lost stability and showed
large variation in throughput.
 At high loads the nodes started competing for
bandwidth ,causing collisions
 AODV performed better in terms of stability.

 AODV doesn’t allow throughput to increase
beyond saturation.

TCP UDP BASED ANALYSIS OF AODV
AND OLSR
 Experimental Setup
 Network simulations are implemented using NS-2
simulator.
 Each node is then assigned a particular trajectory .
 The number of nodes which we take in this is of
about 30.
 In each simulation scenario, the nodes are initially
located at the center of the simulation.

EXPERIMENTAL SETUP
 Data rate of 512 Mbps in UDP and of 1024 Mbps
in TCP is used
 The nodes start moving after the first 20 seconds.

 Constant Bit Rate (CBR) traffic and Internet
Protocol (IP) is used as Network layer protocol.
 the number of traffic sources was fixed at 20

 maximum speed of the nodes was set to 100m /s

 the pause time was varied as 20, 40 ,60, 80 and
100 seconds.

RESULTS AND CONCLUSION
 The AODV protocol will perform better in the
networks with static traffic.
 It uses fewer resources than OLSR.

 The AODV protocol can be used in resource
critical environments.
 The OLSR protocol is more efficient in networks
with high density and highly sporadic traffic.

COMPARISON AND CONCLUSION
 AODV performs efficiently in case of low
bandwidth
 OLSR requires more band width to send TC
messages in case of topology change
 AODV performs better in case of low mobility

 In case of high mobility AODV per packet delay
is increased but is more effective in case of
throughput as compared to OLSR.
 Scalability is limited in case of large network,
AODV suffers flooding and OLSR table grows
 Remarkable to consider to combine both and
have maximum benefit

Computer networks comparison of aodv and olsr in ad hoc networks

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