Transcript end2

END’s Talk
Using Manhattan Mobility Model for the
Counter-Base Broadcasting protocol in
MANETs
Sara Omar al-Humoud
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Outline
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Introduction
Cbase
Mobility Models
RWP
MMM
Results
Future Direction
Research Outline
Contribution
ACBase1
ACBase2
Related
work
Probabilistic
Deterministic
Flooding
Broadcasting
Introduction
Routing
Wireless MANET
Counter Base Broadcast
Scheme
• When receiving a message:
– counter c is set to keep track of number of duplicate
messages received.
– Random Assessment Delay (RAD) timer is set.
– When the RAD timer expires the counter is tested
against a fixed threshold value C, broadcast is inhibited
if c > C.
Comparison
Get the Broadcast ID
Get degree n of node X
c = 1
Flow charts
Get the Broadcast ID
between
n < avg
C = c2
Tmax = Tmax2
Get the Broadcast ID
c = 1
Set RAD [0..Tmax]
C = c1
Tmax = Tmax1
Set RAD [0..Tmax]
same
packet
heard
c = c + 1
While (RAD)
Counter-based
Flooding
same
packet
heard
same
packet
heard
c = c + 1
End while
(RAD)
AdjustedWhile
Counter-based1
End while
C < c
Trans packet
drop packet
C < c
Trans packet
drop packet
Trans packet
drop packet
Adjusted Counter-Based Broadcast
ACBase1 Scheme
• Adjusted Counter-Based Broadcast
– Based on the original counter-based scheme
– Add the ability to decide the counter and the RAD according
to neighbourhood density
– Neighbourhood density is divided according to the Average
number of neighbours into:
• Density1: Sparse
• Density2: Dense
Neighbourho
od
Density
Sparse
Dense
Avg
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Outline
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Introduction
Cbase
Mobility Models
RWP
MMM
Results
Future Direction
Mobility Models
• Traces
MobiLib
• Synthetic Model
– Entity
– Group
Dartmouth
Random Way Point Mobility Model
RWP
How it works:
– at every instant, a node
randomly chooses a
destination and moves
towards it with a velocity
chosen randomly from [0,
Vmax], where Vmax is the
maximum allowable
velocity for every mobile
node.
25 nodes
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Manhattan Mobility Model
MMM
How it works:
– A node is allowed to move along
the grid of horizontal and vertical
streets on the map.
– At an intersection the node can
turn left, right or go straight.
– P of same street = 0.5
– P of turning left = 0.25
– P of turning right = 0.25
MANHATTAN
HOR_STREET_NUM 3
VER_STREET_NUM 3
LANE_NUM 12
25 nodes (3x3 street)
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Outline
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Introduction
Cbase
Mobility Models
RWP
MMM
Results
Future Direction
Prameters
Simulation parameters
Simulation parameter
Value
Simulator
ns-2 version (2.33)
Network Area
1000 x 1000 meter
Transmission range
250 meter
Data Packet Size
256 bytes
Node Max. IFQ Length
50
Simulation Time
900 sec
Pause Times
0 sec
Number of Trials
30
MAC layer protocol
IEEE 802.11
Mobility model
Random waypoint model, Manhattan Mobility Model
Channel Bandwidth
2Mb/sec
Confidence Interval
95%
Packet Rate
2 packets per sec
Node Speed
Max = 30 km_per_hour
Min = 5 km_per_hour
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Performance metrics
• Saved Rebroadcast (SRB)
(r − t)/r
• r = number of hosts receiving the broadcast message
• t = number of hosts that actually transmitted the message.
• Reachability
r/e
•
r = number of hosts receiving the broadcast packet
• e = number of mobile hosts that are reachable, directly or indirectly, from
the source host .
• Average latency
– the interval from the time the broadcast was initiated to the
time the last host finished its rebroadcasting.
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Results
SRB
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Results
Reachability
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Results
Average Latency
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Future Directions
• MMM
– Limiting the number of nodes (cars) in a lane
– Building a bigger map (Glasgow cc)
• Scripting a mobility map generator
• Develop the ACBase2 that calculates the threshold
value according to a function of the number of
neighbours
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Questions
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Introduction
Broadcasting Applications
• Discovering neighbours
• Collecting global information
• Addressing
• Helping in multicasting and Unicast
– Route discovery, route reply
– in on-demand routing protocols like DSR, AODV to broadcast
control messages.
• Conventionally broadcast is done through flooding
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Introduction
Broadcasting Applications
• Flooding may lead to
– Redundancy
– Contention
x Increase in delay
– Collision
x High packet loss rate
– Broadcast storm
problem!
80
70
Number of Messages
x Consume limited bandwidth
90
60
50
40
30
20
10
0
0
1
2
3
4
5
6
7
8
9
Number of Nodes
f(n) = n2 – 2n + 1
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Related work
Probabilistic Broadcasting Methods
• Probability-based
– Rebroadcast with probability P
• Counter-based
– Rebroadcast if the node received less
than Cth copies of the msg
• Location-based
– Rebroadcast if the area within the
node’s range that is yet to be covered by
the broadcast > Ath
• Distance-based
– Rebroadcast if the node did not receive
the msg from another node at a distance
less than Dth
Receiver
rebroadcast
decision
Simple Implementation
RD based on instantaneous information from broadcast msgs
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Related work
Deterministic Broadcasting Methods
• Reliable Broadcast
• Self-pruning
• Scalable broadcasting
• Dominant Pruning
• Cluster-based
Sender
rebroadcast
decision
Elaborate Implementation
Rebroadcast decision based on neighbourhood study
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Related work
Counter-Based related Broadcasting Methods
1. Counter-based broadcast
– Adaptive Counter-based broadcast [Tseng2003]
– Adjusted Counter-Based [Aminu2007]
2. Color-based broadcast [Haddad 2006]
3. Distance-aware counter-based broadcast
[Chen 2005]
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Questions
Towards a better simulation
• Is there a realistic mobility model?
– Obstacle Mobility Model Project 2005
• Ns2, GlomoSim
• the Mobility Management and Networking (MOMENT) Lab,
the Networking and Multimedia Systems Lab (NMSL)
and the Geometric Computing Lab (GCL).
University of Califorrnia at Santa Barbara
– RealMobGen 2008
• Ns2
• Dartmouth's and University of Southern California's
• C. Walsh, A. Doci, and T. Camp, A Call to Arms: It’s Time for REAL
Mobility Models, ACM's Mobile Computing and Communications
Review, to appear 2008
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Questions
Towards a better simulation
• Is there a visualisation tool to view
network topology?
– iNSpect
Mobility files
NS-2
Trace files
iNSpect
OpenGL
animation
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Questions
Towards a better simulation
• How to validate and compare scenarios?
– SCORES tool (SCenariO characteRizEr for Simulation)
Node coverage
Num nodes
Nw diameter
Simulation area
Neighbor count
Transmission range
Foot print
SCORES
…
Mobility file
topology change rate
Metamodels
Delivery ratio, end-to-end
delay, throughput, overhead
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Questions
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