1/17 diane project betreuer: birgitta könig-ries, michael klein an approach to support service...

1/17

DIANE Project

Betreuer: Birgitta König-Ries, Michael Klein

http://www.ipd.uni-karlsruhe.de/DIANE

An approach to Support Service Discovery in Mobile Ad-hoc Networks

- Concept and Simulation -

Universität KarlsruheInstitute for Program Structures and Data Organization

Universität Karlsruhe

Diplomarbeitsvortrag Eduardo Ponz

2/17

Introduction

• Mobile devices are becoming very popular

• We want to link these devices in mobile ad-hoc networks and offer services

• How do we search for a service in such a network?

Summary

Implementation

Concept - Information - Protocols

Scenario

Introduction

Mobile phone PDA Laptop

3/17

Problems with Mobile Ad-hoc Networks

• Highly dynamic topology due to - node movement - node fluctuation- appearing obstacles

• No dedicated server, no physical infrastructure

Summary

Implementation


Scenario

Introduction

4/17

Service Ring (1)

• Group nodes offering similar services into a Service Ring (SR)

DIANE Approach: Service Rings

• One node of the ring becomes the Service Access Point (SAP)

• This node has the description of all the services of the ring

Summary

Implementation


Scenario

Introduction

5/17

Service Ring Model

Service Ring (2)

Many aspects have to be considered in the service ring model:

• Service description

• Service integration

• Motivation

Summary

Implementation


Scenario

Introduction

• Service discovery

6/17

Service Discovery

• Initialization Protocol- How is a service ring built?

• Ring Routing Protocol- How do we find the proper service ring?

• Node Routing Protocol- How do we find the proper service inside a service ring?

• Actualization Protocol- How should the system react to device movement and fluctuations?

Service discovery implies many different aspects

• Ring and Service Information- What information should be stored in the nodes?

Summary

Implementation


Scenario

Introduction

7/17

Service DescriptionOut of the scope ofthe Diploma Thesis

Service Discovery

Ring and Service Information

Information about the service ring has to be locally stored in the nodes

• Service Information

• Ring Information

• Node Information

- Ring ID- Service Type of the SR

- Node ID, Cycle ID- Reachable nodes- Predecessor and Successor

- Services offered by the node

Ring RoutingProtocol

Node RoutingProtocolSummary

Implementation


Scenario

Introduction

8/17

Initialization Protocol

We ask if there is any SR nearbyService Ring?

How to build a service ring from scratch

• else SET node as SAP• If SR then CONNECT to SR

CONNECT:If there is only one node of the SR reachable then

• Build a bridge

If there are more nodes of the SR reachable then

• Insert into SR between the two closest linked nodes

- A second node appears

- A third node appears

- One node appears

SR?

SR?

SAP

Summary

Implementation


Scenario

Introduction

9/17

Node Routing Protocol (1)

How to find the proper service inside a SR

• Routing in a simple SR is trivial

• Each node has one successor and one predecessor

Service D?

Service D

Service A

Service BService C

• How do we deal with intricate rings?

Thanks!

No

Yes, but NOT me

NoYES

but...

• We only have to route the message to the successor node

D

Node X

X‘s Predecessor

X‘s Successor

Summary

Implementation


Scenario

Introduction

10/17


Service rings may be intricate

• Some nodes have more than one successor and predecessor• Some nodes have twice the same successor or predecessorTo properly route a message:

- A message traveling along the SR will keep track of which cycles are already visited

C1

C2

C3

C4

C5

- We divide the service ring into cycles

Summary

Implementation


Scenario

Introduction

11/17


Example of routing a message:

Algorithm for nodes with many successors:

• Continue in the same cycle

Service D?

- If we have twice the same successor- If the other cycles have been partially visited

• Jump to another cycle- If the other cycle is a not visited bridge- If the other cycle is a not visited cycle

Routing complet

e!

Summary

Implementation


Scenario

Introduction

C1

C2

C3

C4

C5

12/17

Ring Routing Protocol

How do we find the proper SR?

We have many different service rings that offer different services

Yellow serviceBlue service

Green serviceIndigo service

The SAPs are connected with each other

Ring of SRs• The SAPs store the information about ring routing

Summary

Implementation


Scenario

Introduction

• A message can now jump to other SRs

13/17

Actualization Protocol (1)

Reactions to device movements and fluctuations

Typical node fluctuations are: • Movement

• Logging

- Into a SR

- Login into a SR- Out of a SR

- Logout of a SR- Sudden disconnection

Summary

Implementation


Scenario

Introduction

14/17

Actualization Protocol (2)

Example of sudden disconnection algorithm:

- Node B vanishes

C

B

D

E

F A

- Node A needs to link with CC is not

reachable!

Backward routing- Node C looks for

reachable nodes- Node C requests

information- Reachable nodes send info

I

I

I

- C processes the info and chooses the best node

- X marks C as successor

- A marks X as successor

X

- The SR is successfully closed

- C sends control message to X

- X sends control message to A

Note: Backward routing should be only used if everything else fails

Summary

Implementation


Scenario

Introduction

15/17

Implementation

A simulation of the Node Routing Protocol in a service ring is currently under development

• QualNet is the network simulator used for this purpose

Summary

Implementation


Scenario

Introduction

- Custom protocols can be developed

- There are pre-written protocol models

- QualNet models complex wireless networks

16/17

Summary and Future Work

Summary:

• A basic mechanism to service discovery has been proposed

Developed Concept Simulation

Ring and Node Information

-

Initialization Protocol -

Node Routing Protocol in progress

Ring Routing Protocol in progress

Actualization Protocol -

Future Work:

• Optimization to the proposed protocols• Implementation of all the protocols in QualNet• Prototype in a real scenario

Summary

Implementation


Scenario

Introduction

17/17

Thank you!

More information on our project web page:http://www.ipd.uni-karlsruhe.de/DIANE

Are there any questions?

Thank you for your attention!

1/17 diane project betreuer: birgitta könig-ries, michael klein an approach to support service...

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