New Approach for Selfish Nodes Detection in Mobile Ad hoc Networks
Sponsored Links
This presentation is the property of its rightful owner.
1 / 21

New Approach for Selfish Nodes Detection in Mobile Ad hoc Networks PowerPoint PPT Presentation


  • 106 Views
  • Uploaded on
  • Presentation posted in: General

New Approach for Selfish Nodes Detection in Mobile Ad hoc Networks Djamel Djenouri: Basic Software Laboratory, CERIST Center of Research, Algiers, Algeria. E­mail: ddjenouri@mail.cerist.dz Nadjib Badache: Computer Science Department, USTHB University, Algiers, Algeria.

Download Presentation

New Approach for Selfish Nodes Detection in Mobile Ad hoc Networks

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


New Approach for Selfish Nodes Detection in Mobile Ad hoc Networks

Djamel Djenouri: Basic Software Laboratory, CERIST Center of Research, Algiers, Algeria.

E­mail: ddjenouri@mail.cerist.dz

Nadjib Badache: Computer Science Department, USTHB University, Algiers, Algeria.

E­mail: badache@mail.cerist.dz

SeCQos Workshop, Athens, September 2005


Outline

1 Overview on Mobile Ad hoc Networks (MANETs) 2 Selfish behavior on packet forwarding problem 3 Watchdog

4 Watchdog’s limitation

5 New Solution

6 Simulation results

7 Perspectives

8Conclusion

SeCQos Workshop, Athens, September 2005


MANET Overview (Definition)

  • A MANET is a collection of Wireless mobile hosts making on the fly a temporary network, without relying on any fixed infrastructure.

  • No central administration exists

  • Mobile hosts cooperate to ensure roles ensured by the fixed infrastructure in traditional networks

SeCQos Workshop, Athens, September 2005


MANET Overview (Multi-Hop)

SeCQos Workshop, Athens, September 2005


MANET’s features

  • Dynamic Topology

  • Limited bandwidth

  • Limited physical Security

  • Infrastructurless

  • Limited energy resources

SeCQos Workshop, Athens, September 2005


Selfish behavior

SeCQos Workshop, Athens, September 2005


Watchdog

•Proposed by Marti et al. In MobiCom 2000

• Many recent sophisticated solutions rely on it in their monitoring component

SeCQos Workshop, Athens, September 2005


Watchdog’s principles

  • Based on the promiscuous mode monitoring and implemented with a source routing protocol.

  • When a node Na sends a packet to Nb to forward to Nc, it monitors it by simply overhearing the channel, it validates the forwarding iff it overhears the packet retransmitted by Nb.

  • This process is generated for each couple of hops in the route

SeCQos Workshop, Athens, September 2005


Watchdog

If packet heard  OK

Else increase Nc’s failure Tally

failure Tally > threshold  the node misbehave

SeCQos Workshop, Athens, September 2005


Watchdog’s detection drawbacks

  • Does not detect correctly and could cause false detections when the power control technique is employed

  • Does not detect selfish nodes in many cases (collisions, partial dropping, collusions)

SeCQos Workshop, Athens, September 2005


SeCQos Workshop, Athens, September 2005


New solution (Two-hop ACK)

  • We propose a new monitoring solution based on two-hop ACK.

  • Assume A monitors B’s forwarding to C, this latter acknowledges each packet by sending a two hop ACK back to A via B.

  • An efficient asymmetric encryption strategy is used to ensure authenticity of ACKs and to prevent the following vulnerability:

SeCQos Workshop, Athens, September 2005


New solution (hop ACK)

  • B misbehaves and drops packets, to circumvent A it sends it a falsified ACK on behalf of C.

  • The encryption strategy we used gets over this vulnerability and,

  • it is relatively of low cost, since it merely encrypts short random numbers, instead of compute digital signature on the packets.

SeCQos Workshop, Athens, September 2005


New solution (hop ACK)

- Decrypts r

- - Checks whether it matches the one it generates

- If so, it validates the forwarding

  • - Generates r

  • Encrypts it with C’s PK

  • Adds it to the packet

  • Decrypts r

  • Encrypts it with A’s PK

  • Adds it to a 2 hop ACK packet

SeCQos Workshop, Athens, September 2005


Simulation results

SeCQos Workshop, Athens, September 2005


Two-hop ACKs Problem

  • The obvious problem of our first solution is the important overhead it engenders, even if the nodes well behave. It requires a two-hop ACK for each data packet, which is costly.

SeCQos Workshop, Athens, September 2005


Perspectives

We plan to complete the proposal by

  • Reduce the overhead

  • Defining efficiently the threshold of accusasion

  • Defining actions that have to be taken when a node is accused as a selfish

  • and particulary by proposing a mechanism allowing nodes to exchange their knowledge regarding nodes that behave selfishly.

SeCQos Workshop, Athens, September 2005


Random two-hop ACK

  • To overcome the two-hop cost, we suggest that A would not continuously ask an ACK, but randomlydecides whether to do so with a probability p, and maps the decision in the packet.

  • This randomization and mapping prevent B from deducing which packet includes an ACK request, and let it motivated to forward all packets

SeCQos Workshop, Athens, September 2005


Random two-hop ACK

  • P is updated according to B’s behavior, it is decreased each time B forward a packet until reaching its minimum value, and set to 1 upon a dropping detection.

  • This way, more trust is accorded to well-behaving nodes and ACK ask is enforced after a dropping, which ensure the efficiency and decreases the cost especially when selfish nodes rate is low, as shown in the simulation results

SeCQos Workshop, Athens, September 2005


Conclusion

  • Our solution is operational regardless the power control employment

  • It reduces the false detection rate with low cost (energy and delay)

  • The random two-hop ACK reduces dramatically the overhead

SeCQos Workshop, Athens, September 2005


?

SeCQos Workshop, Athens, September 2005


  • Login