Security in Mobile Grid Service Varalakshmi P, Thamarai Selvi S, GaneshKumar R, Sundar Raman S

Department of Information Technology

Madras Institute of Technology Chrompet

Anna University, Chennai, Tamilnadu, India

varanip@gmail.com

stselvi@annauniv.edu

ganeshkumar.mit@gmail.com

ssrmit62@gmail.com

Abstract— Mobile Grid is one of the recent emerging

technologies. It has a lot of challenges due to the scarcity

of resources such as processing power, persistent storage,

runtime heap, battery lifetime, memory, bandwidth, and

connectivity and network faults. Dynamic environment affects

both mobile and non-mobile grids. This creates a need for the

virtual administrator. Virtual Organization (VO) is

responsible for resource coordination and to support

Authentication, Authorization and Accounting (AAA).

Dynamic Mobile Virtual Organization (DMVO) has

the property of VO in addition to features such as

workflow initiation and handling of mobile nodes. We

analyze the various types of mobility such as user

mobility, session mobility and resource mobility for

implementing a mobile grid. We have concentrated on the OSI

layered approach for mobile grids and how it helps in the

process execution. We analyzed Service Level Agreement

(SLA) and how it helps for negotiation and

monitoring. We have analyzed the performance

measures for Job Execution Cost, Bandwidth Utilization

Factor, Rejection Ratio for different number of jobs and

various clusters such that each cluster contains different

number of nodes with different configuration. Our main

aim is to decrease the Job Execution Cost and to increase

bandwidth utilization factor compared to the existing scenario.

Keywords: Mobile Grid, Service Level Agreement, Dynamic

Mobile Virtual Organization, Job Execution Cost.

I. INTRODUCTION

Mobile Grid is an emerging grid like Ad hoc and wireless

grids. The Mobile Grid network consists of mobile nodes

that are connected through wireless links, as opposing to the

conventional networks and follow a random topology. This

topology may change dynamically and it is unpredictable.

Mobile Grids are the one that have the capability of

executing any node’s process and send back the result to the

original node that needed the execution of the process. The

characteristics of a mobile network like dynamic topology,

restricted bandwidth, different link capacity and high error

rates makes it hard to bring the security measures in it. But

for the resource sharing and resource coordination we are in

need of a virtual administrator. We simulated three types of

mobility for Grid nodes and how the Mobile Grid works in

these scenarios. For security measure we are in need of a

different SLA that will work on all situations. We

implemented Mobile Grid protocol (MG protocol) that will

support such security measure.

This paper is organized as follows. Session 2 presents the related work on emerging grids particularly Mobile Grid.

Section 3 discusses about the requirement of virtual

administrator in Mobile Grid. Section 4 discusses about the

three mobility types in Mobile Grid. Section 5 discusses

about the Description of the proposed MG protocol. Section

6 discusses the performance evaluation for the MG protocol.

Section 7 gives the conclusion and future work.

II. RELATED WORK

Emerging grids are classified into various types such as

manageable, interactive and user-centric Grids. Knowledge

Grids come under manageable grids. Former is for managing

the human nervous system and support self managing and

the latter represents the usage of different knowledge

management mechanism to support self managing. Personal

Grids come under user centric grids which are similar to

PCs, where each grid is owned by an individual. Interactive

Grids are explicit interactive grids and context aware grids.

In which the former support explicit real time interaction

with users and the later interacts with the surroundings to

build context and adapt their behavior. Mobile Grid, Ad hoc

Grid, Wireless Grid are accessible grids. Ad hoc Grids have

no predefined entry points and wireless grids support

wireless connections between grid nodes and interface.

Konstantinos Katsaros and George C. Polyzos discussed

about why to bring Mobile Grid and they had made a survey

in both technical and business oriented approaches to bring

the Mobile Grids. Stefan Wesner discusses about the

architecture of the Mobile Grid and describes a SIMPLE

protocol for message passing between the agents. F.

D’Andria tells about the theoretical views of the SLA

management subsystem about the SLA management and

SLA negotiation. Waldburger M and Stiller B investigated

in which sense a mobile grid needs functional extensions

and what type of consequences the integration of mobile or

nomadic grid resource will cause. Antonios Litke et al

discussed about the basic infrastructure of mobile grid

services. Sze-Wing Wong and Kam-Wing Ng constructed a

mobile grid agent by combining existing mobile agent

system, Java Agent Development Framework (JADE).

Shang-Fen Guo et al proposed a new service called grid

mobile service (GMS), an extension of grid service and they

discussed about the agent’s lifetime and state evolvement in

GMS. T. Kirkham et al proposed a model for an application

where network based security can be scaled into Grid

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middleware security in a seamless application execution

scenario. Michael Messig and Andrzej Goscinski mainly

concentrated on the need of transparent autonomic

management in service oriented grids and they have

demonstrated the design and implementation of a System

Management Broker.

III. VIRTUAL ADMINISTRATOR FOR MOBILE GRID

A. Mobile Grids

Mobile grids make grid services accessible through

mobile devices such as PDAs and smart phones as in Fig 1.

We usually consider these devices to be at the best

marginally relevant to grid computing because they’re

typically resource limited in terms of processing power,

persistent storage, runtime heap, battery lifetime, screen size,

connectivity and bandwidth.

B. Mobile Grid Architecture

The mobile nodes can be integrated to form an

infrastructure known as a Mobile Grid. Basically a grid is a

system that coordinates resources without the knowledge of

a centralized server. There are three categories of nodes present in a grid Consumer Node (CN), Service Provider

Node (SPN), and Grid Head Node (GHN) where CN

requests a service; SPN provides the service and GHN which

is used to manage all the other nodes. A lot of models are

available to present the Movement of mobile nodes.

Figure 1 Mobile devices and services

C. Dynamics Virtual Organizations

Dynamic Virtual Organizations (DVO) can be applied

for both non-Mobile Grids and Mobile Grids. Dynamics in

non-Mobile Grid systems corresponds to dynamic

organizational constitution and to dynamic process execution

based on only the current needs. But we have to consider

high level of dynamics for Mobile Grids since large number

of handoffs and handovers get executed within a short

interval of time. Mobile Grid increases complexity since the

contents of organizational constitution change rapidly and

we have to maintain the sessions and services in a accurate

manner. Dynamics are used as the key driver for customized

Mobile Grid.

D. Dynamic Mobile Virtual Organization

The target of basic Mobile Grids are service provisioning

for nomadic users. Provisioning often appears in the context

of virtualization, orchestration, utility computing and open

configuration concepts. VO arises due to the strong focus on

inter-domain service provision and service virtualization.

They are also referred to as virtual enterprises or virtual

communities. The concept of VO has been evaluated and its

notion has been evolving over time. VO is considered for

information and communications technology that supports

accountable and chargeable resource coordination across

administrative domains and also to support Authentication,

Authorization and Accounting (AAA). The concept of VO is

changed for Mobile Grids to support Dynamic environment.

Here it refers to the nodes that are not fixed and move to

some other location. It has to be considered well for the

joining and leaving of nodes in a short period of time. The

concept of VO must be employed for resource coordination

and AAA. And it must be extended to support mobility by

adding additional features so that the nodes change their

locations at any point of time and that the workflow is

initiated according to the environment. Generally Grid

follows Distributed mechanisms but Mobile Grid has a

virtual centralized server.

The challenges to be handled while designing a central

administrator are their Membership Management and

Service Provider Selection. The administrator has to handle

the nodes effectively that does not give prior information

about their status. These nodes can go off line at any point of

time. In that stage the node which requests a process from

that off line node gets hanged and does not continue with its

execution. This leads to starvation for some point of time

IV. MOBILITY TYPES AND MOBILE GRID

In a Mobile Grid, all resources need not be mobile.

There are three types of mobility such as user mobility,

session mobility and device mobility. In the device mobility,

the terminals have the capability to move from one IP

(Internet Protocol) subnet to another without any

interruption (session or service interruption). In the user

mobility, as in Fig 2, the mobile devices form a group of

devices with respect to some logic addressing. The group is

addressed by one logic address (1-to-many addressing

scheme whereas one address maps too many logical

addresses). This scheme can also be combined with many-

to-1 addressing where various addresses map to one logic

address. But a given user can access a service or session at

different terminals. In Session mobility, it enables users to

keep sessions when moving from one device to another as in

Fig 3.

The main difference between the session mobility and

user mobility is that session can be only accessible at a

single point of time. By then, sessions are transferred

completely or in parts to any another terminal. These

mobility types are combinable, such that the users can

change the access networks and the service providers.

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Figure 2User Mobility in a Mobile Grid

Figure 3 Session Mobility in a Mobile Grid

A. Mobile Grid Layer

With the general OSI layer, Grid layer is added above

the application layer, as shown in Fig 4. On considering the

Mobile Grids, we should consider each layer to satisfy the

mobile characteristics. The physical layer uses wireless

propagation models such as sky level propagation and line

of sight propagation. In the data link layer, IEEE 802.11

standards are to be followed.

Figure 4 Grid Layer in OSI model

In the network layer, we have to consider routing

protocols such as AODV or DSR. In the transport layer, the

data processing between the two processes and monitoring

the sequential order of the process execution has been done.

The session layer is used to maintain synchronization

between the nodes and it is used to create session mobility

explained above. The presentation layer is the same as that

of the wired layer and the next one is application layer in

which an application is taken into account such as Android

or J2ME to create the user interface for the mobile nodes.

The next one is the grid layer for the execution of the

processes and maintaining the resource coordination and to

handle the vulnerable and off line nodes.

V. MG PROTOCOL

A. Service Level Agreements:

Since the link between the services is present in the Grid

Middleware and the underlying network has to be efficient,

the Mobile Grid computing environment with respect to

business applications becomes very critical in order to

support efficient implementation of monitoring, negotiation

and service management. We have developed a SLA

management subsystem to attain monitoring, negotiation

and service management. A notification mechanism is

added between the grid layer and network layer for effective

communication.

These SLA mechanisms should consider QoS parameters

for grid resources such as CPU use, Memory disk and the

network capabilities such as bandwidth. So, the

application’s QoS requests are mapped on these

infrastructure QoS parameters.

B. MG protocol:

MG protocol is designed to perform SLA negotiation,

monitoring and service management. The MG message

format contains Name, Context, Service Description terms

and Guarantee terms. Name refers to the current node, its

speed of execution and its memory limit. Context specifies

the information about the neighboring nodes and their

status. Service Description says their services, their lifetime

and their capabilities. Guarantee tells their rule for

executing the service, giving the guarantee that it will

execute within the time limit without considering factors

such as node mobility and resource scarcity. We cannot

guarantee that a service cannot be executed that is out of its

capability.

In this protocol, SLA negotiation works as follows. If

two nodes desire to transact in Mobile Grid environment,

the negotiation will share their policies of execution and the

best policy is chosen and it executes the process and the

remaining one is discarded. We can also follow the same

process for very large number of nodes that want to perform

any transaction in a Mobile Grid environment. If the node is

malicious and is problematic in negotiation, an alternate

policy is used immediately. (We have to create the policy

and an alternate policy at the time of SLA negotiation).

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VI. IMPLEMENTATION

Simulation studies are carried out in GloMoSim 2.03

under Linux environment. GloMoSim stands for Global

Mobile Simulator. It is used to build a scalable simulation

environment for mobile and wireless network systems. It is

being designed using the parallel discrete-event simulation

capability provided by Parsec, a C based environment. This

tool is taken since it supports different types of protocol in

each layer and we can add any protocol for our

compatibility.

Most network systems are currently built using a layered

approach that is similar to the OSI seven layers network

architecture. This allows the rapid integration of models

developed at different layers by different people. The

proposed protocol stack will include models for the channel,

radio, MAC, network, transport and higher layers.

We add modules for Mobile Grid by means of adding

another layer that is grid layer and establishing its

functionalities. To establish grid layers we are in need of

parameters such as processing speed, memory, network

bandwidth, network link and so on. We have created three

types of mobility that are already mentioned above. And it

gives better performance for large number of nodes and gets

executed faster due to Parsec which is used for parallel

simulation. We add some modules in driver.pc originally

present in GloMoSim and make it as driver_mobilegrid.pc.

And compile the pc file by means of pcc.

retval = GLOMO_ReadInt(-1,&nodeinput, "PACKET-

SIZE" , &packet_size);

assert(retval == TRUE);

retval = GLOMO_ReadInt(-1,&nodeinput, "PROCESS-

SIZE" , &process_size);

assert(retval == TRUE);

retval = GLOMO_ReadInt(-1,&nodeinput, "PROCESS-

DEADLINE" , &deadline_process);

assert(retval == TRUE);

We made certain fields such as Packet-size, process-size

and process deadline are mandatory. This is used to

determine whether the process can be executed by the

mobile nodes that participate in the Mobile Grid

environment.

If (process_size > no_of_nodes * CPU_memory) the loop is

exited. This constraint should be checked to find the

feasibility of the execution.

Then split the process n times, where n refers to the

maximum number of nodes. If P is the process that is going

to be executed in the Mobile Grid, P = <P1, P2 …Pn>.

Allocate each process with every mobile node <M1, M2…

Mn>. Results are passed to the original nodes and the

messages are sequentially ordered. After this, combine the

execution of all the processes.

To establish security, we go in for SLA agreement and a

new protocol is proposed. It’s necessary to add the

functionality of the protocol, into the driver.pc file. Add the

parameter agreement for that protocol by

retval = GLOMO_ReadInt(-1,&nodeinput,

"AGREEMENT" , &agreement);

If the agreement is not true, then the node will not form

as member in any Mobile Grid environment. The

parameters used for simulation is shown below in table 1.

Table1 Parameters for Mobile Grid Simulation

TERRAIN-DIMENSIONS (1200, 1200)

NODE-PLACEMENT RANDOM

MOBILITY RANDOM-WAYPOINT

MOBILITY-POSITION-

GRANULARITY 0.3333

PROPAGATION-LIMIT -111.0

MAC-PROTOCOL 802.11

NETWORK-PROTOCOL IP

NETWORK-OUTPUT-

QUEUE-SIZE-PER-

PRIORITY

100

ROUTING-PROTOCOL AODV

SEED 27

VII. SIMULATION AND RESULTS

A Job Execution Cost

In a grid, resource prices can vary depending on the

usage (working/non-working time) or the resource load

(peak/off-peak). Each node should have some threshold

cost. This decreases for increasing number of nodes and

increases for increasing number of jobs.

Table 2 Analyzing the Job Execution Cost

Number of jobs Job Execution

Cost

19

34

65

84

97

Existing model

385

480

712

930

1220

Proposed model

357

429

630

810

1005

Table 2 shows the job execution cost for increasing

number of jobs and analyzed in various types of clusters

with each one have different number of nodes and does not

have same configuration. Fig 5 shown below represents the

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Job Execution Cost

1400

1200

1000

800

600

400

200

0

19 34 65 84 97

No of Jobs

Previous Model Our Model

Job Rejection Ratio

0.5

0.4

0.3

0.2

0.1

0

14 22 37 58 67

No oj jobs

Our Model Previous Model

diagrammatic representation of the job execution cost

analysis.

Table 3 Analysis of Bandwidth Utilization Factor

Number of jobs Bandwidth

Utilization

Factor

34

43

62

87

96

Proposed

model

0.26

0.3412

0.492

0.690

0.761 Existing

model

0.20

0.2559

0.369

0.517

0.571

Figure 5 Analysis of Job Execution Cost

B. Bandwidth Utilization Factor

The ability to reserve network bandwidth is a critical

factor for the success of high-performance mobile grid

applications. Reservation of light paths in dynamically

switched optical networks facilitates guaranteed bandwidth.

However, reservation of bandwidth can often lead to

bandwidth fragmentation which significantly reduces

system utilization and increases the blocking probability of

the network.

C. Rejection Ratio

Rejection ratio depends on the following factors: number

of available resources in the grid and total number of jobs.

The jobs get rejected unexpectedly due to the mobility of

nodes. It does not follow any probability distribution but

follows random process.

of SPN

Bandwidth = Total number of jobs / Total number

Bandwidth factor = Bandwidth * Constant_factor.

Figure 7 Analysis of Job Rejection Ratio

We can increase / decrease the number of jobs and number

Bandwidth utilization factor increases when the number

of jobs gets increased and decreases when number of nodes

get increased.

Bandwidth Utilization Factor

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

34 43 62 87 96

Number of Jobs

Our Model Previous Model Figure 6 Analysis of Bandwidth Utilization Factor

Figure 6 shown above and Table 3 shown below

represent the analysis of Bandwidth Utilization Factor in

diagrammatic representation and Data set formats.

of SPNs. Figure 7 shown above and Table 4 shown above

represent the analysis of Job Rejection Ratio in

diagrammatic representation and Data set formats

Table 4 Analysis of Job Rejection Ratio

Number of jobs Job Rejection

Ratio

14

22

37

58

67 Proposed

model

0.04

0.08

0.28

0.2

0.26 Existing model 0.06 0.12 0.24 0.26 0.34

The performance measure for Job Execution Cost,

Bandwidth Utilization Factor, and Rejection Ratio are found

by changing the number of nodes in each cluster, number of

jobs and also changing the number of clusters.

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VIII. CONCLUSION AND FUTURE WORK

In this paper, we proposed a Mobile Grid protocol for

Mobile Grid’s Service Level Agreement. And then we have

modified the code of original GloMoSim that is actually

designed for wireless environment and make that for Mobile

Grid environment. This MG protocol will provides the

Mobile environment. If there are anomalies in the cluster

then it cannot form the Mobile Grid group. We have

decreased the Job Execution Cost and the rejection ratio,

and thereby effectively improving the bandwidth utilization

compared with the existing conventional model. SLA

negotiation and validation is done which will increase the

job execution speed. And we also simulated with various

type of mobility which can be made possible for any type of

job that is being executed. In future work we have to add

functionalities or should use some other simulator to make it

feasible for heterogeneous environment. We have to make

continuous assessment to decrease the rejection ratio and to

improve the bandwidth utilization factor.

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[2] Michael Messig, Andrzej Goscinski, “Autonomic system

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Morariu, “Identity Management in a Mobile Grid Environment”, Proceedings of the UK e-Science All Hands Meeting 2007, ISBN 978-0-9553988-3-4, pages 636-642,

Sep.2007

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[5] Francesco D’Andria, Josep Martrat ,Giuseppe Laria, Pierluigi

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[7] Antonios Litke, Dimitrios Skoutas, Theodora Varvarigou,

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