Optimizing the Routing within Fisheye Scope for LANMAR

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CS215 Project
Optimizing the Routing within Fisheye Scope for
LANMAR
Dan Pei Mengqiu Wang March 20, 2001
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Outline

• ? Problem of the original LANMAR
• ? Optimized Link State Routing (OLSR)
• Simulation and Experiments
• ? Conclusion and Future work

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Problem with the original LANMAR
? Routing scheme within a Fisheye scope --
every node periodically exchanges topology
information only with its neighbors -- updates
only contain entries for the nodes within its
fisheye scope and the landmark nodes -- at the
same time, nodes exchange a distance vector of
all landmarks with neighbors -- as a result,
each node will maintain accurate topology
information about its neighborhood and a distance
vector to all landmark nodes
? Problem As the network density increases,
it becomes inefficient -- the number of
neighbors grows largely, then ! Storage --
Topology information kept by each node increases
dramatically ! Bandwidth -- information
exchanged increases dramatically
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Optimized Link state routing (OLSR)
? Link state routing -- has many advantages,
like converging quickly and the shortest path
routing -- the only problem is the
unaffordable flooding overhead ? Multipoint
Relay (MPR) -- Each node selects a subset of
its neighbors as MPR The node is called
MPR selector of its MPR set -- Each node only
sends out topology information about its MPR
selectors -- A node forwards updates only if
it is the senders MPR
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Optimized Link state routing (OLSR)
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Optimized Link state routing (OLSR)
? Calculate MPR set -- Some definition MPR(X)
Multipoint relay set of node X running this
algorithm N(X) One hop neighbor set of node
X N2(X) Two-hop neighbor set of node X, not
including one-hop neighbors D(X, Y) The number
of one-hop neighbors of node Y, which is a member
of N(X) -- Algorithm 1. Start with an
empty MPR(X) 2. For each node Y in N(X),
calculate D(X, Y) 3. First select those
nodes in N(X) which provide the only path to
reach some node in N2(X) as MPRs
4. While there still exist some nodes in N2(X)
not covered by MPR(X), do 4.1 For
each node Y in N(X), calculate the number of
nodes in N2(X) not covered by MPR(X), but
reachable through Y, say R(Y) 4.2
Select that node in N(X) which has the maximum
R(Y). In case of a tie, select the node as MPR
whose D(X,Y) is greater.
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Simulation and Experiments
? Goal compare the performance of OLSR with
FSRL ? Simulation -- simulate OLSR in
Glomosim environment -- combine with Landmark
routing replace the routing scheme within
fisheye scope Each node exchanges topology
information with its neighbors Such updates
only include information about its MPR
selectors MPRs forwards these updates Such
forwarding is only limited within the fisheye
scope of senders -- we call it MPRL (
MPR-Landmark) ? Performance metrics --
Delivery rate the ratio of packets totally sent
to packets totally received -- End-to-End
Delay the time delay between a packet is sent
out until it is received -- Bandwidth Cost
the total number of bytes are used in topology
information exchanging
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Simulation and Experiments

• Experiment Parameters
• Field range 1000m X 1000m
• Bandwidth 2Mbits/s
• Transmission range 150 meter
• Mobility Random Waypoint Reference Point
  Group Mobility,
• 10s pause time
• Traffic pattern 10 randomly chosen pairs
• CBR 1packet/2second, 512 bytes/packet.
• Simulation time 10 minutes
• Fisheye Scope 2 hops
• Landmark Interval one update / 0.5s
• Groups 4
• FSRL parameter one topology update / 2s
• MPRL parameters Hello interval 0.5s, TC
  interval 2s

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Simulation and Experiments
? Experiment Set I Fixed mobility at 2m/s, node
number changes from 100300. ? Experiment Set
II Fixed node number at 200, change mobility
from 0m/s10m/s
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Experiment Set I (1)
Bandwidth cost VS Topology density
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Experiment Set I (2)
Delivery rate VS Topology density
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Experiment Set I (3)
End-to-End delay VS Topology density
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Experiment Set I Analysis
? Bandwidth VS. Density -- Nscope neighbors
within scope ? (2Transmission Range)2
density -- N1hop one-hop neighbor ?
(Transmission Range)2 density -- FSRLs
Topology Update Size O(Nscope N1hop)
O(density2) -- For MPRL Hello Size
O(N1hop) O(density) TC Size O(Mpr
Selector) O(N1Hop) O(density) ? Delivery Rate
VS. Density -- FSRL and MPRL take the same
Landmark protocol(including election and
drifters) -- What makes the difference
Only symmetric connection can be used to route
data packet in MPRL Routing Control Packets
compete with the data packets ? End-to-End delay
VS. Density -- Routing accuracy contributes
-- Routing Control Packets compete with the data
packets
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Experiment Set II (1)
Bandwidth cost VS Mobility
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Experiment Set II (2)
Delivery rate VS Mobility
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Experiment Set II (3)
End-to-End delay VS Mobility
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Experiment Set II Analysis

• ? Bandwidth Cost VS. Mobility
• -- Neither of MPRL and FSRL changes greatly
  with mobility, but MPRL performs better
• ? Delivery Rate VS. Mobility
• -- Both drop with mobility increase( because
  routing accuracy decreases)
• End-to-End Delay VS. Mobility
• -- Neither of MPRL and FSRL changes greatly
  with mobility, but MPRL performs better
• -- Only symmetric connection can be used to
  route data packet in MPRL

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Conclusion and Future work

• ? Conclusion
• -- We implemented and improved OLSR,
  integrated with Landmark Routing.
• -- Simulation results show that
• With high node density, MPRL performs much better
  in terms of Bandwidth cost, End-to-End Delay, and
  Delivery rate.
• When mobility increase, MPRL performs better in
  Bandwidth cost, end-to-end delay. But only
  slightly better in Delivery rate.
• ? Future work
• Extensive simulation to find an optimal
  configuration for MPRL