Prophet Address Allocation for Large Scale MANETs Matt W. Mutka Dept. of Computer Science & Engineering Michigan State University East Lansing, USA IEEE INFOCOM 2003

Outline Introduction Related Work Prophet Allocation Performance Analysis Simulation Conclusion

Introduction Hard-Wired Network Automatic address allocation DHCP MANET Automatic address allocation Instability of mobile nodes Low bandwidth Openness of MANET Lack of central administration

Motivation Avoid address conflict A feasible auto-configuration algorithm should handle the following three scenarios: A mobile node simply joins a MANET and then leaves it forever. A MANET partitions and then the partitions merge later. Two separately configured MANETs merge

Introduction - Scenario A

Introduction - Scenario B

Introduction - Scenario C

Related Work - Allocation Method Conflict-detection allocation Trial and error Conflict-free allocation Divided to disjoint part Best-effort allocation DDHCP( Maintain a global allocation state) Prophet allocation Local communication Even distribution

Prophet allocation - Assumption R is a range of avilable IP address range. f(n) is integer sequence consisting of numbers in R The initial state of f(n) is called the seed. The interval between two occurrences of the same number in a sequence is extremely long; The probability of more than one occurrence of the same number in a limited number of different sequences initiated by different seeds during some interval is extremely low.

Prophet allocation - Protocol Example A 1.Choose random IP and random state value (address, state of f(n)) B 3.A Use f(n) to generate IP and state value 2.When B Join and ask A for Free IP 4.Assign the generated IP and state address to B 5.A change its state value accordingly

Prophet allocation – Protocol Describtion Random IP and random state value (address, state of f(n)) B approaches A and asks A for a free IP f(n)=(3x3x11)mod 7=1 so A change the state of f(n) to 1 and assign to B. C join and D join, approaches A and B, asks for a free IP f(n)=(3x1x11)mod 7=5 and f(n)=(1x1x11)mod 7=4 If there are more node join -><- because the small range of R

Prophet allocation – Partition and merge Scenario B Cause the sequences are different Scenario C We designate the first node in the MANET to generate the random network ID(NID)

Prophet allocation – Design of f(n) Generate different k-tuples. If k=4 A is (address,(e1,e2,e3,e4)) Address= (a+2 e1 3 e2 5 e2 7 e3 ) 1.The under-line element increase by 1 2.The new node get the ip and underline shifts right 1

Protocol Un-initialized Local conflict resolution Configured Waiting 1.Switch to ad-hoc mode and broadcast state request (one hop broadcast) 2.Retries <=k Repeat Broadcast 3. if Received Response IP address Intial state value NID else set to defult 5. Send HELLO Msg when received state request reply and update state 6.If received different NID switch to Local conflict resolution 7.Finish 8.Ends the session

Performance evaluation Distributed operation Correctness Complexity Communication overhead Evenness Latency Scalability

Performance comparison Characteristics summary Qualitative evaluation

Simulation - Assumption DSR routing protocol Mobile nodes join the MANET every 30 seconds Simulation for 3 nodes The area size was chosen to make all the nodes connected in the topology.

Simulation - Communication Overhead

Simulation - Latency

Conclusion Prophet allocation is for large scale MANETs, Low complexity, Large communication, Even distribution Low latency.

Thank You