An Efficient Quorum-based Fault-Tolerant Approach for Mobility Agents in Wireless Mobile Networks

Yeong-Sheng Chen Chien-Hsun Chen Hua-Yin Fang

Department of Computer Science, National Taipei University of Education

Outline

Introduction Related Work Cyclic Quorum-based Replication

Mechanism Performance Evaluation Conclusion

Introduction

Mobile IP Protocol is a protocol to support Hosts mobility.

The architecture of mobile IP Mobile Host (Mobile Node) Mobility Agent

Home Agent Foreign Agent

Introduction

HA

MN

RAN

Router

Radio Access Network

Home Agent

Introduction

HA

MN

FA FA

FA

FA

RAN

Router

RouterRouter

Router

Router

Internet

Internet

Introduction

HA

MN

FA FA

FA1

FA

RAN

Router

RouterRouter

Router

Router

Register

HA allocates an addressand maintains the MN

A

Router

Internet

Internet

Send data to A through HA and FA1

MN

Introduction

HA

FA FA

FA

FA

RAN

Router

Request Care-of AddressAllocate CoA or DHCP

Tell HA stores MN’s CoA

MN

Introduction

HA

FA FA

FA

FA

RAN

Router

A

A wants to send data to MN

Introduction In multiple mobility agents

environment, data will be distributed stored in the different agent.

Distributed data processing will cause some problem Fault tolerance Registration delay Load balance

Introduction

HA

MN

FA FA

FA

FA

HA crashed

Introduction To offer solutions to these problems,

many fault-tolerant approaches have been proposed.

R. Ghosh and G. Varghese, “Fault-Tolerant Mobile IP,” Technical Report WUCS-98-11, Washington Univ., Apr. 1998.

Related Work- FTMIPP

HA

A

FA

FA

RAN Router

Router

Router

Registration request

Acquire Home Address under HA

Update HA’s bindings

Update HA’s bindings

Related Work- FTMIPP

The drawback of FTMIPP Long registration time Low resource utilization

Conclusion Use fully redundant mobile agent to

solve fault tolerant problem

Related Work

J. W. Lin and J. Arul, “An Efficient Fault-Tolerant Approach for Mobile IP in Wireless Systems,” IEEE Transactions on Mobile Computing, VOL. 2, NO. 3, Jul.-Sep. 2003. .

HA

A

FA

FA

FA

Search MNsResponseRequest to store the bindings

OA&M

(Operation Administration

and Maintenance)

Detect failed

Manage the region belong to HA

Related Work

HA

A

FA

FA

FA

Request to Restore

OA&M

HA recovered

Related Work

The drawback of the scheme Spend extra time on

Searching MNs Delivering bindings

Extra hardware cost

Goal The backup mechanism

should maintain and backup bindings efficiently

should not bring heavy system load should balance

Many researches use quorum-based mechanisms to backup data in distributed systems.

Cyclic Quorum-based Replication Mechanism Assumption

Not all HAs of a quorum in a home network will fail at the same time.

Whenever a HA crashes, any data in the volatile media of the HA will be gone

The failure occurs in the network only by reason of the faulty HA

The home network will divide into several network segments and each HA will take charge of one of the segments.

Cyclic Quorum-based Replication Mechanism To balance the backup load, the

author uses quorum to achieve the goal

Per-allocate the storage place with location by using quorum

Cyclic Quorum-based Replication Mechanism Cyclic Quorum-based could balance t

he load

1NN-1…..4231 2 3

Cyclic Quorum-based Replication Mechanism

Quorum type Quorumproposed

Quorum Size

Voting Weighted Majority

Hierarchical Quorum Consensus

Grid Rectangular Grid N=R*C

Square Grid

Triangular Grid

Tree Tree

Cycle Circle

12

N

63.0N

12 N

N2

2

1N

N

M. J. Yang, Y. M. Yeh, and Y. M. Chang, “Legion Structure for Quorum-Based Location Management in Mobile Computing,” Journal of Information Science and Engineering, Vol. 20, pp. 191-202, 2004.

Cyclic Quorum-based Replication Mechanism

1NN-1…..423

There are N HAs in the networks and N distinct quorum

According to Cyclic Quorum, each HAs need backup bindings of other HAsN

Cyclic Quorum-based Replication Mechanism Example:

There are 8 MAs in the network The Quorum sets ={Q1,Q2,Q3….,Q8} Ex. Q1={HA1,HA2,HA3}, Q2={HA2,HA3,HA4},

Q3={HA3,HA4,HA5},……Q8={HA8,HA1,HA2}

HA1 selects Q1, HA2 selects Q2

…………,HAN selects QN

12

345

6

7

8

Cyclic Quorum-based Replication Mechanism

12

345

6

7

8 12

345

6

7

8 12

345

6

7

8 12

345

6

7

8

12

345

6

7

8 12

345

6

7

8 12

345

6

7

8 12

345

6

7

8

Q1 Q2 Q3 Q4

Q5 Q6 Q7 Q8

Cyclic Quorum-based Replication Mechanism

HA1 stores in 3 quorums EX. HA1 stores in {Q1,Q7,Q8} for

backup

12

345

6

7

8 12

345

6

7

8

Q7 Q8

12

345

6

7

8

Q1

Cyclic Quorum-based Replication Mechanism

HA1

MN

RAN

RouterRouter

Router

HA7

HA8

HA1 will sends the bindings to HA7 and HA8 periodly

Cyclic Quorum-based Replication Mechanism

If HA1 failed, HA7 and HA8 will takeover the member of HA1

12

345

6

7

8 12

345

6

7

8 12

345

6

7

8

Q1Q7 Q8

Cyclic Quorum-based Replication Mechanism

If HA1recovers, HA7 and HA8 will sends the bindings to HA1

12

345

6

7

8 12

345

6

7

8 12

345

6

7

8

Q1Q7 Q8

Performance Evaluation

Simulator :QualNet Compare with FTMIPP

Performance Evaluation

Number of MNs

Bin

din

gs

per

back

up H

AFTMIPP

CQFTP

Performance Evaluation

Number of MNs

Extr

a B

ack

up M

ess

age

FTMIPP

CQFTP

Performance Evaluation

Number of Multiple HAs

Nu

mb

er

of

reg

iste

red

MN

per

Backu

p H

A

9 16 25 36 49 64 81

FTMIPP

CQFTP

Performance Evaluation

Number of Multiple HAs2 4 6 8 10 12 14 16 18 20

Avera

ge R

eg

istr

ati

on

Dela

y (

Sec)

FTMIPP

CQFTP

Performance EvaluationA

vera

ge R

eg

istr

ati

on

Dela

y (

Sec)

Mobility Rate

FTMIPP

CQFTP

Conclusion

The authors proposed a mechanism Don’t need any extra hardware cost Reduce backup bindings by using the

small quorum size Balance the load of take over process Low registration overhead