enhancement of passive cluster based routing protocol for mobile adhoc networks wang, sheng-shih may...

Enhancement of Passive Cluster Based Routing Enhancement of Passive Cluster Based Routing Protocol for Mobile Adhoc NetworksProtocol for Mobile Adhoc Networks

Wang, Sheng-Shih

May 29, 2003

Aja Rangaswamy and Hung Keng PungSchool of Computing, National University of Singapore

IEEE International Conference on Computer Communications and Networks (ICCCN 2002), 2002, pp. 376-381

May 29, 2003May 29, 2003 Sheng-Shih WangSheng-Shih Wang

OutlineOutline

Dimension Analysis Passive Cluster-Based Routing Protocol (PCBRP) Enhanced PCBRP Simulation Results Conclusion


Fixed Mobility GroupMobility

Bluetooth802.11 DCF

802.11 PCF

3GNo-locationinformation

Location-Awareinformation

Single Source

Multiple Sources

Combine

farer

20munknown

known

interference

Interference-free

Distributed

Cluster-based

Single channelMultiple channel

QoS-based

Non-QoS

Non-Backup

Backup Single layer

Multi-layer Ad-hoc

Intra-net

Inter-net

Routing Multicasting

Geo-casting

Broadcasting/Flooding

Data collection

Traffic reduction

Power saving

Bandwidth management

Role change

Restructuring

Singlechip

Dualchips

Quorum

Parallelism

10m

Non-Obstacle

Obstacle

Construction

TDMA

FDMA

CDMA

HiperLAN

GSM2.5G

UWB

MultipleDest

SingleDest

Permutation

Initialization

Partialsum

Linear array Ring

TreeMesh

Toric

Hyper-cube OtherLoad

balance

Non-Loadbalance

FFT

Sorting

MatrixMultiplication


PCBRP PCBRP --- References

Mario Gerla, Taek Jin Kwon, and Guangyu Pei, “On Demand Routing in Large Ad Hoc Wireless Networks with Passive Clustering,” WCNC, Sep. 2000.

Yunjung Yi, Mario Gerla, and Taek Jin Kwon, “Efficient Flooding in Ad hoc Networks using On-Demand (Passive) Cluster Fiormation,” MobiHoc 2002.

Yunjung Yi, Taek Jin Kwon, and Mario Gerla, “Passive Clustering (PC) in Ad Hoc Networks,” Internet Draft, draft-ietf-yi-manet-pac-00.txt, Nov. 2001.


PCBRP PCBRP --- Properties

An on-demandon-demand routing protocol Less control overheadoverhead Only somesome nodesnodes has to broadcast the RREQ packets


PCBRP PCBRP --- Node Types

Clusterhead The representative of each node in the same cluster

Gateway Belong to more than two clusters at the same time

Ordinary

Cluster Head Gateway Ordinary


PCBRP PCBRP --- Node States

External States INITIALINITIAL, CLUSTERHEADCLUSTERHEAD, FULL GATEWAYFULL GATEWAY, DISTRIBUTED DISTRIBUTED

GATEWAYGATEWAY, ORDINARYORDINARY

Internal States CLUSTERHEAD READYCLUSTERHEAD READY, GATEWAY READYGATEWAY READY

CLUSTERHEAD

FULL GATEWAY

DISTRIBUTED GATEWAY

ORDINARY


PCBRP PCBRP --- External Node States

INITIALINITIAL The state that a node just starts upstarts up

CLUSTERHEADCLUSTERHEAD When an initial node receives a packet from a non-cluster headnon-cluster head

node, it sets its internal state to CLUSTERHEADCLUSTERHEAD READYREADY If the node in the CLUSTERHEADCLUSTERHEAD READYREADY state has an outgoing

packet of data it changes its state to CLUSTERHEADCLUSTERHEAD

FULL GATEWAYFULL GATEWAY When a node can hear from twotwo clusterheadsclusterheads, it declares itself as

a GATEWAYGATEWAY It acts as a bridgebridge between the two clusters


PCBRP PCBRP --- External Node States (cont.)

DISTRIBUTED GATEWAYDISTRIBUTED GATEWAY When a membermember of one cluster is within the hearing range of a

member of another clustermember of another cluster, then both the nodes become distributed gateways

ORDINARYORDINARY A node, which is a membermember of a cluster and does not assume any

of the above-mentioned roles, changes its state to ORDINARY NODE

Such nodes nevernever forward any requests but remain in the network in a passive way


PCBRP PCBRP --- Internal Node States

CLUSTERHEAD READYCLUSTERHEAD READY The candidatecandidate for CLUSTERHEAD When an INITIALINITIAL node receives a packet from a non-cluster headnon-cluster head

node, it changes its state to CLUSTERHEAD READY

GATEWAY READYGATEWAY READY The candidatecandidate for CLUSTERHEAD When an ordinary node or an initial node detects a shortage of detects a shortage of

gateway nodesgateway nodes, it changes its state to GATEWAY READYGATEWAY READY When this Gateway Ready node has an outgoingoutgoing packet, it

changes its state to that of a FULL GATEWAYFULL GATEWAY or DISTRIBUTEDDISTRIBUTED GATEWAYGATEWAY based on the Distributed Gateway Selection Mechanism


PCBRP PCBRP --- Working Mechanism

At cold start All nodes are in the INITIALINITIAL states

For a node wishing to transmit data Broadcasting RREQ packet to find the destination Any other node in its hearing range, which is in INITIAL state,

receives this packet and changes its own state to CLUSTERHEADCLUSTERHEAD READYREADY

When the CLUSTERHEAD READY node transmits the packet, it sets its state to CLUSTERHEADCLUSTERHEAD

All nodes within the range of this CLUSTERHEAD become membersmembers (gatewaygateway or ordinaryordinary) of this cluster


PCBRP PCBRP --- Working Mechanism (cont.)

The Lowest ID ruleLowest ID rule When two or more nodes want to compete for the state of

CLUSTERHEAD The node with the lowest idlowest id keep its statekeep its state

Member nodes that can hear from twotwo or moremore clusterheadsclusterheads declare themselves as FULL GATEWAYSFULL GATEWAYS

Member nodes of a cluster that can hear from member member nodes of another clusternodes of another cluster become DISTRIBUTEDDISTRIBUTED GATEWAYSGATEWAYS

All otherother membermember nodes change their state to ORDINARYORDINARY


PCBRP PCBRP --- Shortcomings

Unstable In lowlow or irregularirregular traffictraffic loadsloads The clusters may break downbreak down frequently

Loss of critical path For certain configurationscertain configurations

A node is within the transmission range but no route to it

Unnecessary route request queries Some nodes can be identified as redundantredundant

Packet with the incorrect sequence If packets arrive out-of-orderout-of-order at the destination and the packets

contain differentdifferent statesstates (i.e., the sending node changed its state between transmission of multiple packets), then the destination node will be misledmisled about the true stateabout the true state of the source node


Enhanced PCBRP Enhanced PCBRP --- Features

Improving Cluster Stability ALIVEALIVE control packet

ALIVE packets are sent only when a clusterhead has no data to send has no data to send for CLUSTER_TIMEOUT number of secondsfor CLUSTER_TIMEOUT number of seconds


Enhanced PCBRP Enhanced PCBRP --- Features (cont.)

Preventing Loss of Critical Path When an INITIALINITIAL node is only within the range of an ORDINARYORDINARY

node

Solution When an INITIAL node issues a request and receives no reply, it waits

for the INITIAL ROUTE REQUEST TIMEOUTINITIAL ROUTE REQUEST TIMEOUT, and then changes its state to CLUSTERHEADCLUSTERHEAD

isolation



Preventing Unnecessary Broadcasts Scenario

CLUSTERHEAD or GATEWAY rebroadcastrebroadcast the RREQ even if the destination is within the same clusterwithin the same cluster

CollisionsCollisions and high cluster traffichigh cluster traffic RedundantRedundant broadcastsbroadcasts, which will be unnecessarilyunnecessarily forwarded to other

clusters

Heuristics (Selective re-broadcastsSelective re-broadcasts) For GatewayGateway drop drop the packets For ClusterheadClusterhead unicastunicast



Synchronizing packet arrival order by sequence numbers Every node that sends out a packet appends a sequence number appends a sequence number

to the packetto the packet Receiving nodes record the sequence number and they update

states of the sending nodes in their node list only if the current sequence number is greater thangreater than the sequence number previously received from that host


Simulation Simulation --- Environment

Approaches BFBF, PCBRPPCBRP, and PCBRP-optPCBRP-opt

Parameters

Number of nodes 100

Area of Simulation 1000m 1000m

Type of Topology Flat

Range of Each Node 250m

Highest Mobility (meters/sec) 0, 2, 4, 8, 16

Simulation time (sec) 600

Number of Route Requests 300 (randomly distributed)


Simulation Simulation --- Rate of successful Route Request Queries

The number of dropped packets increases


Simulation Simulation --- Number of broadcasts

With isolated nodes

The period of no traffic cause the complete break-up of clusters


Simulation Simulation --- Percentage of packet dropped

• collision• queue overflow• congestion


Enhanced PCBRP Enhanced PCBRP --- Control Packets


ConclusionConclusion

Enhanced PCBRP Sequence NumberingSequence Numbering INITIAL node timeout mechanismINITIAL node timeout mechanism Periodic ALIVE messagePeriodic ALIVE message Selective broadcastsSelective broadcasts Unicast Route Request QueriesUnicast Route Request Queries

Advantages Fewer broadcastsFewer broadcasts Lower rate of dropped packetsLower rate of dropped packets Retransmission of packets is reducedRetransmission of packets is reduced



Preventing Loss of Critical Path When an INITIAL node is within the range of an ORDINARY node

only

Solution When an INITIAL node issues a request and receives no reply, it waits

for the INITIAL ROUTE REQUEST TIMEOUT, and then changes its state to CLUSTERHEAD



Preventing Unnecessary Broadcasts Scenario

CLUSTERHEAD or GATEWAY rebroadcast the RREQ even if the destination is within the same cluster

Collisions and high cluster traffic Redundant broadcasts, which will be unnecessarily forwarded to other

clusters

Heuristics Selective re-broadcasts

If a gateway node receives a broadcast (RREQ) from another gateway node within the same cluster, then the packet is silently dropped

If a clusterhead receives a request and the destination node is a member of the same cluster, then the clusterhead will unicast the route request to the member node



Use of sequence numbers to synchronize packet arrival order


Simulation Simulation --- Environment

Number of nodes 100

Area of Simulation 1000m 1000m

Type of Topology Flat

Range of Each Node 250m

Highest Mobility (meters/sec) 0, 2, 4, 8, 16

Simulation time (sec) 600

Number of Route Requests 300 (randomly distributed)


Simulation Simulation --- Rate of successful Route Request Queries


Simulation Simulation --- Number of broadcasts


Simulation Simulation --- Percentage of packet dropped


Enhanced PCBRP Enhanced PCBRP --- Control Packets


Enhanced PCBRP Enhanced PCBRP --- Summary for 100 and 200 nodes

Simulation Parameters Improvement over PCBRP Improvement over BF

Successful RREQs 3% 4%

No. of Broadcast/RREQs 7% 53%

No. of Packets dropped 33.3% 100%

No. of Control packets -14% N/A

Simulation Parameters Improvement over PCBRP Improvement over BF

Successful RREQs 3.6% 6.7%

No. of Broadcast/RREQs 12% 47.8%

No. of Packets dropped 39% 83%

No. of Control packets -12% N/A


ConclusionConclusion

Enhanced PCBRP Sequence Numbering An INITIAL node timeout mechanism A periodic ALIVE message Selective broadcasts Unicast Route Request Queries

Advantages Fewer broadcasts Lower rate of dropped packets Retransmission of packets is reduced

enhancement of passive cluster based routing protocol for mobile adhoc networks wang, sheng-shih may...

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