scalable team multicast in wireless ad hoc networks exploiting coordinated motion mario gerla...
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Scalable Team Multicast in Wireless Ad hoc networks Exploiting Coordinated Motion
Mario GerlaUniversity of California, Los
Angeles
Introduction Many team-orientedteam-oriented operations in MANET
scenarios Search and rescue, disaster relief operation,
battlefields Each team tends to move together (affinity team
model) a chosen node (e.g., landmark) can represent a team
Often, all nodes or none in a team join a multicast group
Affinity team model simplifies mobility handling, and thus allows a scalable multicast protocol design
LANMAR (Landmark ad hoc routing protocol) works well with affinity team model
Introduction (2) Proposed idea, two-tier team multicast, team multicast, called
M-LANMARM-LANMAR Unicast tunneling from the sources to the
representative of each subscribed team Flooding within a team
Advantages of M-LANMAR High reliability via unicast tunneling and
flooding Easy to manage the large networks based
on motion affinity model
LANMAR (Landmark Ad Hoc Routing Protocol) –
Background
Proactive Routing Efficient handling affinity team model Using the notion of landmarks to keep track of logical
subnets (teams) Using two routing schemes
A local proactive routing: within a limited scope, nodes exchange their routing table each other
A long haul distance vector routing: a landmark of each subnet is propagated to the whole network
Routing Tables Local routing table Landmark table
LANMAR-Example
Logical SubnetLogical Subnet
LandmarkLandmark
node1node2
LM1 LM2
LM3
Landmark Table of node1(subnet_addr, lm_addr, nextHop, …)
Node3 (src)
node3LM3subnetAddr3
node3LM2subnetAddr2
node2LM1subnetAddr1
Local Routing Table of node1(destAddr, nextHop, …)
…
Node3Node3
Node2Node2
dest
Long haul routinglocal routing
M-LANMAR(Multicast-enabled LANMAR)
Extension of LANMAR Proactive scheme Supporting both unicast and multicast routing
with very low extra overhead Scalable as the network size and number of
groups increase Join MC group: advertising by piggybacking
subscribed multicast groups IDs to landmark broadcast packets
Leave MC group: simply not advertising/timeout The sources can find joined teams in their
landmark table
Source node
LM1 LM2
LM3
Subscribed Teams
LM4
Tunneling
Flooding
Flooding
Scope = 2
Scope = 2
(MC1)
MC1
MC1
node3LM2subnetAddr3
node3LM4subnetAddr2
node2LM1subnetAddr1
Landmark table of source node
…
Simulation Compared with
ODMRP (On Demand Multicast Routing Protocol) Flooding
Environments QualNet 2.9 Each source generates data in a CBR fashion Transmission range: 376m, bandwidth 2Mbits Network size: 6000 x 6000 m2
Nodes: 1000 nodes into 36 teams Mobility: 2 m/s with 10 seconds pause time
Following “Reference Point Group Mobility” Packet size: 512 bytes
Simulation Results – Static Network (1000 nodes, 3teams for each
group, 1pkts/sec)
As the number of multicast groups increases ODMRP suffers from large control overhead and
collisions M-LANMAR achieves high delivery ratio (by unicast
tunneling and flooding)
Number of MC Groups(#) Number of MC Groups(#)
Delivery
Ratio
Norm
alized CT
RL
O
H
Simulation Results – Mobile Network(1000 nodes, 3teams for each group, 2m/s, 10p)
4pkts/secODMRPM-LANMARFLOOD
1pkt/secODMRPM-LANMARFLOOD
Simulation Results – Mobile Network(1000 nodes, 3teams for each group, 2m/s, 10p) (2)
As the number of multicast groups increases With small number of groups, ODMRP
outperforms M-LANMAR because of its mesh-based multicast structure (redundant paths); M-LANMAR potentially experiences many link breakages
With large number of groups, flooding suffers due to heavy overhead
With high offered load (right), M-LANMAR outperforms ODMRP (ODMRP suffers from heavy redundant forwarding)
Reliable Multicast Support Reliable Adaptive Lightweight Multicast (RALM)
Targeting general multicast protocols NACK-Oriented mechanism Rate-based congestion control
Send-and-wait mechanism (freeze the sender’s buffer upon receiving a NACK); congestion handling
Round-robin recovery Sources recover the lost pkts for each NACKER one at a
time in a round-robin fashion Prevent ACK implosion
Combining with M-LANMAR Only landmarks (say representatives) send feedback
(e.g. NACK/ACK) to the source Prevents unnecessary feedback implosion
Simulation Results with RALM (1000 nodes, 3teams for each group, 2m/s, 10p, 5 multicast groups) –Delivery ratio
Delivery Ratio
0
0.2
0.4
0.6
0.8
1
1.2
512 1024 1280 1689.6 2560 5120
Offered Load (Bytes/sec)
Deliv
ery
Ratio
M- LANMAR w/ UDP ODMRP w/ UDPM- LANMAR w/ RALM ODMRP w/ RALM
•Same parameters to the mobile network experiment•Increase the offered load (number of pkts/sec)•ODMRP suffers from feedback implosion
Simulation Results with RALM (1000 nodes, 3teams for each group, 2m/s, 10p, 5 multicast groups) –Throughput
Throughput
0
5000
10000
15000
20000
512 1024 1280 2560 5120
Offered Load (Bytes/sec)
Thr
oug
hput
(Bits
/sec
)
M- LANMAR w/ UDPODMRP w/ UDPM- LANMAR w/ RALMODMRP w/ RALM
Discussions Possible extensions of M-LANMAR
Efficient resource discovery via content based multicast
Use existing MANET multicast protocols to multicast a packet to all landmarks
Scalable as the number of teams increases Provide a congestion controlled reliable
transport layer like TCP between the sources and the landmarks
Conclusion Propose a new multicast paradigm
Team multicast Design M-LANMAR as an example of team
multicast Study the performance of M-LANMAR compared
with ODMRP and FLOOD Flat multicast has scalability limitations M-LANMAR provides an efficient platform for a reliable
and congestion controlled multicast protocol (e.g., TCP) Apply a reliable transport protocol, RALM over M-
LANMAR and ODMRP M-LANMAR is an efficient platform for a reliable multicast
protocol
Thank you
Any Questions?