performance analysis of aodv and saodv routing protocols in ad-hoc mesh networks- a simulation study...
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Performance Analysis of AODV and SAODV Routing Protocols in Ad-Hoc Mesh
Networks- A Simulation Study
Sangeeta GhangamSangeeta GhangamDivision of Computing Studies, Arizona State UniversityDivision of Computing Studies, Arizona State University
July 30, 2007July 30, 2007Advisor: Prof. Bruce MillardAdvisor: Prof. Bruce Millard
Introduction to Mesh Networks• Wireless Mesh Networks(WMNs) have a 3-tier
architecture where different protocols work in tandem
• Infrastructure, client and hybrid WMN’s• WMN’s have several applications
Metro area coverage, Military applicationsDisaster recovery, Intelligent transportation systems
• Examples:MIT’s RoofNet- An experimental WMNTempe, Gilbert, Chandler, and Philadelphia – city
WMN
Wireless Mesh Network
A Survey of Wireless Mesh Networks, IEEE Radio Communications, pp S23—S30, Sept 2005
WMN’s & Mobile Ad-hoc Networks (MANET’s)
• WMN’s diversify the capabilities of MANET’s• IEEE 802.11’s Extend Service Set (ESS) mesh
networking task group is working on a routing protocol for WMN based on AODV(Ad-hoc On demand Distance Vector)
• BelAir, Tropos, Strix Systems, Cisco etc. have WMN products using routing protocols based on AODV
Why AODV?• A reactive protocol which
finds routes on demand• Low overhead and adjusts
to dynamic environment• Provides loop free routes
with the use of sequence #’s
• Has both unicasting & multicasting capability
• Works in 3 modes Route discovery Route maintenance Local connectivity
management
Reverse Path Setup Forward Path Setup
C.E.Perkins, E.M.Royer, “Ad-hoc On-Demand Distance Vector Routing”, Proc. of ACM, 2002
AODV
• AODV works in a implicit ‘trust your neighbor’ mode
• Two main security requirementsNode AuthenticationMessage Integrity
• Secure AODV (SAODV) adds an extension to different AODV packet formats to incorporate digital signature for protecting the non-mutable information and hash chains to protect the mutable information(hop count)
OPNET: The Simulation Environment
• Provides an OOP approach to network design
• Has a hierarchical modeling architecture similar to the structure of communication networks
• Provides ease of use via a GUI or the flexibility to create custom models via programming interface
• Integrated post simulation analysis tools
Designing the SAODV Model• SAODV model in OPNET follows from
the pre-existing AODV model• Implements the hash chain
functionality• New data structures for packet
formats• New functions to implement the
revised packet creation, memory allocation & de-allocation etc. has been created
• A cryptoSys API toolkit, which implements a random number generator & MD5 hash algorithm, from DiManagement services (http://www.di-mgt.com.au/crypto.html) is use
The Hash Chain Mechanism Creation(RREQ (Route REQuest)and RREP(Route
REPly)):Set Max-hop-count = TTL (time to live)
Generate a Random Number ( seed) Calculate Top-hash = h max _hop_count ( seed) Set Hash = seedSend:
Type, Length Hash- function, Max-hop-count, Top-hash& Hash fields with the original AODV RREQ and RREPVerification:
Top_hash== h (max_hop_count – hop_count) (Hash)Account for the additional hop h( Hash)
Network Model for Comparisons in OPNET
Server
IP backbone
Gateway1 Gateway2
RRRR
BSS4BSS3BSS1 BSS2
Simulation ParametersParameters Values
Room Size 4000m x 4000mMobile Nodes 2 in each BSS
Mobility
Random WaypointSpeed - 2m/s to 7 m/s
Start: Uniform( 0, 100)sPause: Uniform(50, 100)s
Mac Layer Wired Links: 100 Base TWireless Links: IEEE 802.11g @ 11Mbps
Routing Protocols Wired Links: OSPFWireless Links: AODV/SAODV
Application TrafficStartEnd
RequestResponse
Request/hr
BurstyUniform(100,110)s
Poisson (9000)Poisson (4000)Poisson (8000)Poisson (80)
Simulation Time 200 minutes
Metrics
Throughput (bits/sec)Route discovery time(sec)
Delay (sec)Routing traffic sent ( bits/sec)
Routing traffic received ( bits/sec)Load (bits/sec)
Throughput & DelayTh
roug
hput
(bits
/sec
)
Del
ay (s
ec)
Time Time
SAODVSAODV
AODVAODV
SAODVSAODV
AODVAODV
SAODV has a higher delay and throughput for a similar sized network even with less number of nodes creating application traffic.
Load & Route Discovery Time
Time
Load
(bits
/sec
)
Rout
e di
scov
ery
time
(sec
)
Time
SAODVSAODV
AODVAODVSAODVSAODV
AODVAODV
SAODV and AODV have comparable route discovery time.SAODV though imposes a higher load on the network than AODV.
Routing Traffic Received & Sent
Time Time
Routi
ng T
raffi
c Re
ceiv
ed (
bits
/sec
)
Routi
ng T
raffi
c Se
nt (
bits
/sec
)
SAODVSAODV
AODVAODV
SAODVSAODV
AODVAODV
SAODV is bandwidth intensive compared to AODV as it has a higher amount of control traffic.
Scalability of AODV and SAODV
Time
Rout
e D
isco
very
Tim
e (/
sec)
Time
Rout
e D
isco
very
Tim
e (/
sec)
50 nodes
30 nodes15 nodes
50 nodes
30 nodes15 nodes
AODVAODV SAODVSAODV
The Route Discovery time more than doubles, as the number of nodes increases for AODV and SAODV.
Summary & ConclusionsSummary: SAODV model created in OPNET and compared against the
existing AODV model. Different sized networks designed for comparing and
analyzing the protocols.Conclusions: Both SAODV and AODV show comparable results up to a
mid-sized network of about 30 nodes with some mobile nodes.
AODV performs well over different network architectures and is well suited for mesh networks.
SAODV only works well in a single tier and hence cannot be used without modifications for mesh networks.