END’s Talk
Using Manhattan Mobility Model for the
Counter-Base Broadcasting protocol in
MANETs
Sara Omar al-Humoud
1
Outline
•
•
•
•
•
•
•
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
6
Outline
•
•
•
•
•
•
•
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
9
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)
10
Outline
•
•
•
•
•
•
•
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
12
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.
13
Results
SRB
14
Results
Reachability
15
Results
Average Latency
16
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
17
Questions
18
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
20
10
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
21
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
22
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]
23
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
30
Questions
Towards a better simulation
• Is there a visualisation tool to view
network topology?
– iNSpect
Mobility files
NS-2
Trace files
iNSpect
OpenGL
animation
31
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
32
Questions
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