Wireless Grid

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Wireless Grids - Amin Ghadersohi 1

Wireless Grids

Amin Ghadersohi

Department of Computer Science and Engineering, SUNY-Buffalo,

NY.

4/4/2005


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Overview

Introduction

What is the Grid?

What is Grid Computing?

Wireless Grids

Motives and Driving Forces

Infrastructure

Performance

Hybrid Grid Project Proposal

Grid Examples


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Introduction

I think there is a world market for maybe 5computers. Thomas Watson (IBM), 1943

Computers in the future may weigh no more than1.5 tons. Popular Mechanics, 1949

Data Processing is a fad that wont last out theyear. Business Book Editor Prentice Hall, 1957

There is no reason anyone would want a computer

in their home. Ken Olsen (President DEC), 1977 640K ought to be enough for anybody. -Bill Gates,

1981


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What is the Grid?

Grids have moved from the obscurely academic to

the highly popular. Compute Grids, Data Grids, Science Grids, Access

Grids, Knowledge Grids, Bio Grids, Sensor Grids,Cluster Grids, Campus Grids, Tera Grids, and

Commodity Grids. So what exactly is the Grid?

a funding conceptand, as industry becomes

involved, a marketing slogan. The word Grid is chosen by analogy with the electric

power grid.


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What is the Grid?

A Three Point Grid Checklist*

1. Coordination of resources that are not subject tocentralized control;

2. Use of standard, open, general-purpose protocols

and interfaces; and3. Delivery of nontrivial qualities of service.

The end user does not have to know or care wherethe computing is performed or the data stored.

*I. Foster, What is the Grid? A Three Point Checklist, Argonne National Laboratory,http://www- fp.mcs.anl.gov/~foster/Articles/WhatIsTheGrid.pdf, 2002.


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What is the Grid?

Characteristics of current Grid system

Large-scale Heterogeneous

Dynamic resource sharing relationship

Service Oriented/Policy Driven

The essence of Grid Technology is

virtualization, the ability to abstract thephysical datacenter into a set of logicalcomponents.


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Wireless Grids

The emergence of the Wireless Grid meets

all these criteria and is fueled bytechnological advances in two major areas:

Grid Computing

Wireless Technology Pros and Cons

Pros: ubiquity, availability, productivity

Cons: constraints of wireless network Unpredictable network quality Lowered trust and robustness

Limited local resources and battery lifetime for mobile devices


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What is Grid Computing?

Distributed, high performance computing and

data handling infrastructure that: Incorporates geographically and organizationally

dispersed, heterogeneous resources (computing

systems, storage systems, instruments, and otherreal-time data sources, human collaborators, and

communication systems)

Provides common interfaces for allresources.


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Grid Architecture

Open Grid Services Architecture (OGSA)

Virtual Organization (VO): a set of individuals or institutionsthat provide or request resources.

Service orientation: everything is service.

Service virtualization: definition separated from

implementation. Service semantics -- the Grid Service: standard interfaces of

interoperability

Discovery: service data, service registration, service data retrieving

Dynamic service creation: service factory Lifetime management: service destroy and termination, keep alive

Notification

Ian Foster, Carl Kesselman, Jeffrey M. Nick, Steven Tuecke, "The Physiology of the Grid: An OpenGrid Services Architecture for Distributed Systems Integration." Open Grid Service InfrastructureWG, Global Grid Forum, June 2002.


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Related Technologies Cluster computing

Primarily concerned with a collection of homogeneous computational

resources. Physically bound.

Could be a grid node.

CORBA CORBA was a precursor to the Web (grid) services world we live in today.

Foundation for Java Remote Method Invocation (RMI)

DCE DCE (Distributed Computing Environment) is not so much an architecture as

it is an environment.

Facilitate distributed computing.

P2P

E.g.: KaZaA Lacks a central point of management.

anonymity and some protection from being traced.

Scalability

More tolerant of single-point failures than grids


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Utility Computing is

One of Several Commercial Drivers

(Based on a slide from HP)shared, traded resources

value

clusters

grid-enabled

systems

programmable data center

virtual data center

Open VMS clusters,TruCluster, MCServiceGuard

Tru64, HP-UX,Linux

switch

fabriccompute storage

UDC

computingutility or

GRID

today

Utility computing

On-demand

Service-orientation

Virtualization


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Utility Computing


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Grid Computing - Next Internet

NETWORK

IMAGINGINSTRUMENTS

COMPUTATIONALRESOURCES

LARGE DATABASES

DATA ACQUISITION PROCESSING,ANALYSIS

ADVANCEDVISUALIZATION

Grid Computing: Concepts, Applications, and Technologies Ian Foster, May 2002


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The Global Community


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Wireless and Mobile Applications


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So Far

Introduction

What is the Grid? What is Grid Computing?

Wireless Grids

Motives and Driving Forces

Infrastructure

Performance

Hybrid Grid Project Proposal

Grid Examples


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Research Challenges in Mobile Grid

Environments

InternetInternet

LAN

Grid

LAN Grid

Wire/Wireless

Gird

Arrivingusers/serversDeparting

users/servers

Static model

Stable servers

Stable users

Dynamic model

WLAN Grid

HeterogeneityHeterogeneityIntermittentIntermittent

AvailabilityAvailability

Small devicesSmall devices

Power deficiencyPower deficiency Limited NBWLimited NBW

MobilityMobilityNatureNature

SecuritySecurity

DynamicDynamic

ConnectivityConnectivity

http://www.wirelessgrids.net


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Driving forces

New User Interaction Modalities and Form

Factors Extend UI to small screens, small keyboards, and

other I/O modalities.

Speech

Issue of mobile device connectivity

Limited Computing Resources

Mitigate the constraints imposed by limitedresources of mobile devices.


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Driving Forces

Additional New Supporting Infrastructure

Elements Address new applications that involve dynamic

and unforeseen events.

Rapid provisioning of major amounts of computationaland communications bandwidths.


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A Scenario

Other scenarios: scientific application,commercial business

Forest fire

Firemen

Firemen

FiremenFiremenComputation center

History databases

Geographic

databases

Fire simulationWeather forecast

Wireless

links


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Marketting the wireless gridA self-sufficient economic model for mobile devices involved in grid computing.

T. Phan, L. Huang, C. Dulan, Challenge: Integrating Mobile Wireless Devices Into the Computational Grid,Proceedings of the 8th annual international conference on Mobile computing and networking. September 2002,pp 271-278.


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Grid Classification by Architecture

Classification by Architecture

Degree of heterogeneity of the actual devices Level of control exercised by those who own and

administer the devices.

Local Cluster or Homogeneous WirelessGrid

Wireless devices that share the same hardwarearchitecture and the same operating systems.

E.g.: Network of mobile handheld devices forcoordinating medical personnel in the hospital.

A. Agrawal, D. Norman, A. Gupta, Wireless grids: approaches, architectures, and technical challenges, MIT

Sloan Working Paper No. 4459-04; Eller College Working Paper No. 1016-05


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Wireless Intra-Grids

Encompasses wireless devices that belong to multipledivisions or communities within an actual organization(AO).

Divisions may be located in different geographies.

Divisions may be governed by a separate set of policies.

But there exists a level of trust and oversight so that groundtruth may be known with respect to identity andcharacteristics.

E.g.: wireless grid that simultaneously supports the mobile

sales force of a company and the networks of wirelesssensors used by the manufacturing division for trackinginventory


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Inter-Grid

Encompasses multiple AOs and transcends greateramounts of geographical, organizational, and other types of

differences, such as ones related to intellectual property

rights and national laws.

Resource management and policy integration (security,authentication and data management tasks) attain greater

complexity due to the scalability requirements.

A (potentially) universally accepted method for the

composition of declarative policies must be proposed andaccepted.

Commonly accepted semantics for the expression of policy.


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A. Agrawal, D. Norman, A. Gupta, Wireless grids: approaches, architectures, and technical challenges, MIT

Sloan Working Paper No. 4459-04; Eller College Working Paper No. 1016-05


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Grid Classification by Usage Pattern

Computational Grid

Virtual metacenter. Large amount of computing and data resources.

Data Grid

Provide shared and secure access to distributed data.

Large scale data processing and management that require

the participation of world wide researchers.

Utility Grid

Human interface of computational Grid and Data Grid.

Parasitic Computing, A-L Barabasi, V. W. Freeh, H. Jeong, J. B. Brockman, Nature, Vol. 412, 30 August 2001.


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Wireless Grid Contributions

Computational Grid

Ability to borrow computational resources fromothers.

Power limitations of mobile devices limits their

computational capabilities.

Cooperative or parasitic*.

E.g.: Wireless sensor network used to monitor

conditions for predicting natural calamities like

earthquakes or volcanoes.

Parasitic Computing, A-L Barabasi, V. W. Freeh, H. Jeong, J. B. Brockman, Nature, Vol. 412, 30 August 2001.


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Data Grid

Provide shared and secure access to distributeddata.

Integration and reconciliation of underlying data

semantics continues to challenge evolving technology.


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Wireless Grid Contributions Data Grid

ExamplePatient needs blood

Hospital issues query to

medical history databases

through its mobile network

Mobile ISP notifiespotential donors

Responses processed

and reconciled

Patient Gets blood


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Utility Grid

Also referred to as Access Grid Ubiquitous access to specialized pieces of

software and hardware

Users can request resources when needed (on-demand)

On-demand access to all kinds of resources

Only be charged for the amount being used. Can subsume both Computational and Data grids


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Wireless Grid Contributions Utility Grid

Example

Traffic conditions

and routing

Commercial products

and services

Instantaneous

decisions and

Transactions

Processing power

where its neededSensor networks


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Wireless Grid Resources

Provide a virtual pool of computational andcommunications resources.

Computing Power Overcome limited computation power on mobile devices by

distributing task across multiple devices.

Need for appropriate collaborative processes between thesegeographically distributed tasks.

Storage Capacity No more limited storage problem.

Distribute data across multiple devices. Avoid contention through the application of advanced

synchronization techniques.


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Wireless Grid Resources

Communications Bandwidth

Remote access, and high QoS.

Multiplicity of Applications

Ubiquitous access to a wide variety of

applications. Overcome the need to install these applications on

separate mobile devices.


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Grid Topology

A number of researchers have evaluated the

topology and configuration of mobile networks1

. standalone in nature.

Commercial wireless grids need to possess some

access to the Internet and wired Grid infrastructure;

therefore it is better to follow a hybrid model by

integrating Baseline devices into current wired grids.

It will consist of Mobile Ad-hoc Networks2 (MANET) type

systems with multiple-hop paths between mobile nodesand access points to the wired network.

1MANETconf: Configuration of Hosts in a Mobile Ad Hoc Network, S. Nesargi, R. Prakash, in Proc. of INFOCOM02, 1059-1068, 2002.Weak Duplicate Address Detection in Mobile Ad Hoc Networks, N. H. Vaidya,MIBIHOC2002, June 2002.

IP Address Assignment in a Mobile Ad Hoc Network, M. Mohsin, R. Prakash, IEEE Military Communications Conference (MILCOM 2002), Vol. 2, 856-861, October 2002.

2 http://www.ietf.org/html.charters/manet-charter.html


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Infrastructure

Grid systems are usuallyarranged in a hierarchal

manner, with a set ofnodes designated as thegateway.

The gateway managestasks such as:

Node management, Task allocation, and

Brokering.

All nodes on the grid willrun a client application

implementing a lightweight communicationsprotocol for informationexchange with the grid.


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Infrastructure - Brokering Service

Brokering Service The Brokering Service

facilitates all communication among thedevices participating in the grid activities1.

Two major information stores:

Active Agent Repository (AAR)

Task Allocation Table (TAT).

1A collaborative problem-solving framework for mobile devices, S.Kurkovsky, Bhagyavati, A. Ray, ACMSE '04, April 2-3, 2004.


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Infrastructure - Brokering Service

AAR contains information about all computingdevices that are available to the grid All mobile devices within a given wireless cell.

CPU rating, amount of available memory and the current levelof the battery charge.

TAT contains information describing how each

distributed task is allocated across the agents on thegrid. Information stored in TAT evolves as the distributed task

gets closer to completion.

When agents complete their partial tasks, they return theresults back to the Brokering Service, which stores them inTAT where they await to be requested back by the initiatorof the corresponding task.


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Infrastructure - Keep-Alive Server

All communication aspects of the grid

infrastructure are handled by the Keep-AliveServer.

sends and receives messages to and from all

computing devices available on the grid. All devices entering the wireless cell and willing to

participate in the distributed grid tasks advertise

themselves as available to the Keep-Alive Server.


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Performance Issues

Problems arise since meaning of performance isextended Computational performance: scheduling

Energy: power management and offloading

Unstable network: adaptation

Security

Addressing and naming

Discovery

Policies

A lot can be borrowed from other research areas, but

they should be put into a real Mobile Grid framework forinspection.


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Performance Issues

The mobility of the Baseline devices in the grid is a

critical factor affecting the performance of the entiregrid.

Directly affects the time it may take to perform a

computationally-intensive task.

Mobile devices overwhelming the underlying services suchas the Brokering service and Keep-Alive server.

Instability due to large number of mobiles leave the cell at

the same time.

Lack of sufficient resources.

Load balancing techniques to address this issue.


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Performance Issues

A related issue is that of agents systems leaving the grid whilepartial tasks are still in progress.

A solution is to re-allocate these partial tasks to other agentspresent on the grid.

Another approach is to allow agents to carry their partial taskswith them when they leave the grid and migrate to a new servicearea.

Handoff issues become paramount. What is to happen when the initiator of a task moves to a new area?

If the grid were to facilitate task completion even when the initiatorhas migrated to a different area, handoff issues once again become asignificantly complicating factor. Soft handoff has to be ensured for the agent migration so that the user is

unaware of the underlying issues involved with migration. Handoff issues need to be addressed by architecture.

Frequent disconnections lead to poor QoS.


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Performance Issues: Application Level

Scheduling Goal of scheduling: maximize application performance.

Application Level Scheduling (AppLeS)

An application-specific approach to build scheduler for parallel applicationson heterogeneous systems.

Comprehensive system and application information

Static information

User-specified application parameters

Application performance model Dynamic information: Network Weather Service

Performance prediction: Network Weather Service

Experience the system from the point view of application

Run-time scheduling: Information is applied to application model to estimate

application performance and choose an optimal resource allocation from aset of viable configurations.

F. Berman, R. Wolski, S. Figueira, J. Schopf, and G. Shao, "Application-Level Scheduling on

Distributed Heterogeneous Networks." In Proceedings of Supercomputing 96, Pittsburgh, PA, Nov.1996.


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Scheduling Algorithms: host-satellite

systems Host-satellite system

A powerful host and many less-powerful satellites

Offloading computation from satellite to host to

maximize overall performance Fit the scenario of mobile environment

Partitioning algorithm Requirements

Serial program

Pipeline processing Chain structure

Construct assignment graph for the partition problem. Weight for edges (Wh, Ws)

Find the optimal sum-bottleneck path in the

assignment graph Complexity: O(n2loge)

Shahid H. Bokhari, "Partitioning problems in parallel, pipelined and distributed computing." IEEE

Transactions on Computers, 37(1):48-57, 1988.

host satellites

s

1 2 3 4

1 2 3 4

1 2 3 4

t

1

2

3

1 2 3 4


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Saving energy.

Energy crisis of mobile devices Performance also concerns energy

Energy consumption estimation Simulation: SimplePower, Wattch

Empirical methods

Ways to save energy

Dynamic power management (DPM) policies: tradeoffbetween energy and performance Spin down disks

Turn off screen

Network interface hibernation

Processor voltage scaling Comprehensive stochastic model

Computation offloading


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Policy optimization of DPM Policy optimization

Most aggressive policy is not acceptable.

Find the balance of aggressiveness to optimize performance and energy consumption.

Stochastic model: Discrete-time Markov decision processes Model: service provider, service requestor, queue

Power manager makes random decision according to current state of SP, SR, Q, at each timeperiod.

Minimize performance penalty while keeping average energy consumption and request lossbelow some levels specified by users.

Advantages: generality, abstraction, non-determinism.

G. A. Paleologo, L. Benini, A. Bogliolo, G. De Micheli, "Policy Optimization for Dynamic Power

Management." Design Automation Conference, pp. 182-187, June 1998.

Power Manager

Service Provider Service Requestor

Queue

Observation

Command(on/off)

Request(0/1)

offonOff/0.8On/1.0

Off/0.2

On/0.0

Off/0.0

On/0.03

Off/1.0

On/0.97

Service Provider

100.95

0.05

0.12

0.88

Service Requestor

10-,0/1.0

On,1/0.8

Off,1/0.0

-,0/0.0

On,1/0.2

Off,1/1.0

on,0/0.8

On,1/0.0

Off,-/0.0

On,0/0.2

On,1/1.0

Off,-/1.0

Queue


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Computation offloading

Scheduling in terms of energy: Offloading can reduce computation, but communication also

consumes energy

Optimize energy consumption by offloading part of computation Model a program

Task definition: each call site (statically); each invocation(dynamically)

Cost graph

Relationship between tasks and data Node weight indicating power consumption of computation and

communication

Edge weight indicating mean number of times for tasks accessing data

Aggregate the consumption from the cost graph and optimize

Zhiyuan Li, Cheng Wang, Rong Xu, "Computation offloading to save energy on handheld devices: a

partition scheme." In Proceedings of the international conference on compilers, architecture, andsynthesis for embedded systems, Atlanta, Georgia, USA, 2001.


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Disconnected Operation

Another fact affects performance: unpredictablenetwork link quality Solution: adaptation

Disconnected operation in Coda file system Definition

a mode of operation that enables a client to continueaccessing critical data during temporary failures of a shared

data repository. Solution: proxy + cache

Venus: client-side proxy

Three working states Hoarding (Caching)

Emulation Reintegration

James J. Kistler, M. Satyanarayanan, "Disconnected Operation in the Coda File System." ACM

Transactions on Computer Systems, Feb. 1992, Vol. 10, No. 1, pp. 3-25.

Hoarding

Emulation Reintegration

Disconnection

Physical

reconnection

Logical

reconnection


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Application-aware adaptation

Application-aware adaptation model Operating System notifies application of relevant changes.

Accurate and timely information.

Application decides how to adapt to the changes Design of Odyssey: proxy again

Extension of NetBSD Typed data

Working model: Application requests data within a range of availability Odyssey returns data or notify change

Application re-request data of different quality usingdifferent range

Implemented as VFS in NetBSD system Requests are intercepted as system call

Advantages: agility, smooth running, support of concurrency

Brian D. Noble, M. Satyanarayanan, Dushyanth Narayanan, James Eric Tilton, Jason Flinn, Kevin R.

Walker, "Agile Application-Aware Adaptation for Mobility." In Proceedings of the 16th ACMSymposium on Operating System Principles, St. Malo, France, Oct 1997.

Application

warden

warden

warden

interceptor

Odyssey

viceroy

Kernel

syscall Odyssey

call

upcall

b l


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Mobile Security

Difficulties of security in wireless mobileenvironment Inherent vulnerability of wireless media

Performance impact!

Charon: indirect authentication using Kerberos Extend Kerberos by inserting a remote proxy (again!!)

between client and other servers

Secure channel is built by first granting the proxy service toclient

Proxy interacts with other servers on clients behalf

Client can be very small: only need DES encryption/decryption

No compromise of security: The communication between client and proxy is encrypted

Proxy believes the identity of user

Proxy does not possess clients session key and private key

Armando Fox, Steven D. Gribble, "Security on the move: indirect authentication using Kerberos." In

Proceedings of the second annual international conference on Mobile computing and networking(MobiCom'96), Rye, New York, United States, 1996.

Add bili d l i i d d i


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Address mobility and location independent naming

Wireless mobile networks

Nomadic network: Mobile IP Ad hoc network: ad hoc routing protocols

Nomadic network Ad hoc network

M bil IP


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Mobile IP

Problems Stable connection requires stable IP stable routing no mobility

Solution: associate two IPs with one host (one for identification, one for

routing)

Mobile IP

Charles E. Perkins, "Mobile IP", IEEE Communications Magazine, May 1997.

Home

Network

Home

NetworkForeign

Network

Foreign

Network

IP Host

Home

Agent

Foreign

Agent

Home IP Care-of IP

Home IP

Tunnel

Intercept

Ad h k


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Ad hoc network

No static or centralized infrastructure

Packet relay: routing

Efficient routing protocols are required to address Power limitation of the end devices

Consideration for stable wireless connectivity, routeoptimization and efficient use of the limited bandwidth.

Data will need to flow across the grid using a combinationprotocols

Mobile IP

Ad-Hoc routing protocols: Dynamic Source Routing Protocol (DSR) and

Ad hoc On-Demand Distance Vector Routing (AODV) Zone Routing Protocol (ZPR) Hybrid routing

Ad h i


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Ad hoc routing

Ad-hoc On-Demand Distance Vector Routing (AODV)

Pure on-demand route acquisition

Discover and maintain a route to another node onlywhen Need to communicate with the node

Current node acts as an intermediate forwarding node

Timeout to purge outdated path

Only reinitiate path discovery when moving node lyingalong active path

Monotonic increasing sequence number to supercedestale path

Pros: scalability, efficiency, responsiveness to change

C. E. Perkins, E. M. Royer, "Ad-hoc On-Demand Distance Vector Routing." In Proceedings of the

2nd IEEE Workshop on Mobile Computing Systems and Applications, New Orleans, LA, February1999, pp. 90-100.

Ad h ti


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Ad hoc routing

The Dynamic Source Routing protocol (DSR)

Simple and efficient routing protocol designedspecifically for use in multi-hop wireless ad hoc

networks of mobile nodes.

Completely self-organizing and self-configuringnetwork.

No need for any existing network infrastructure or

administration.

Dynamic route discovery

Dynamic Source Routing in Ad Hoc Wireless Networks, D. Johnson, and D. Maltz, Mobile

Computing, Vol353. Chp 5, pp. 153-181, 1996.

Ad h ti


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Ad hoc routing

Zone Routing Protocol (ZRP) combines: Proactive protocol: which pro-actively updatesnetwork state

and maintains route regardless of whether any data trafficexists or not

Reactive protocol: which only determines route to adestination if there is some data to be sent to

thedestination All nodes within hop distance at most dfrom a node X are

said to be in the routing zone of node X g All nodes at hopdistance exactly dare said to be peripheral nodes of node

Xs routing zone. Pro-actively maintain tables

Dynamically discover routes. Similar to DSR.

Peer to peer reso rce ro ting


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Peer-to-peer resource routing

Difference with Grid No distinguished server: anywhere (scalability)

Unstable nodes: join/leave (reliability)

Problems: how to find resource in peer-to-peer network? Keep each resource location at each node: not scalable

Flooding (Gnutella): not scalable

Centralized index server (Napster): single failure

P2P routing algorithms (distributed hash table): Content Addressable Network (CAN): distributed 2D hash table

Chord: ring-based structure

Pastry: Plaxton-tree based

Tapestry: Plaxton-tree based

Similarities and differences between ad hoc routing and P2P routing Sims: high mobility and low reliability of nodes, hop by hop connection, flat

network topology, etc.

Diffs:purpose of usage, node-node connection, abstraction level, routing table,etc.

Pastry 43C942 2 L2L3


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Pastry

Plaxton-tree-like structure Distributed tree structure where every node is the root of a tree

Simple mapping from object ID to root ID of the tree it belongs to

Nodes keep nearest neighbor pointers differing in 1 ID digit Hashed ID for both node and document

Routing table (O(logN)): digit similarity

Leaf set: numerically closest nodes

Routing (O(logN) hops) First check leaf set Then use routing table to forward message (1+ more digit)

Finally check ID with longest prefix and closest value

Pros Highly distributed (reliability)

Scalability Efficiency

A. Rowstron, P. Druschel, "Pastry: Scalable, distributed object location and routing for large-scale

peer-to-peer systems." IFIP/ACM International Conference on Distributed Systems Platforms(Middleware), Heidelberg, Germany, pages 329-350, November, 2001.

4227

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42A2

L1 L1

L2

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L3

CE75 39AA

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4361

437A

43784378

4378

Discovery Semantics and Protocols


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Discovery Semantics and Protocols

Service description protocols are needed to describethe services provided by various components of the

wireless grid. Once the services are published, a discovery

protocol is needed to map the mobile resources tothe services. The notion of grid service can be

extended to the wireless grids. Some work has been performed towards providing

naming service for MANET systems.

The mobile nature of the wireless grid components

makes it challenging to provide for discoverymechanisms across virtual organizations.

Policy Management


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Policy Management

Since the end-devices or nodes can be power

constrained, one cannot assume that the devices

are capable of running complex protocols such as

Lightweight Directory Access Protocol (LDAP) or

Common Open Policy Service (COPS).

Need to address policies that govern the usage,privileges, access to resources, sharing level

agreements, quality of service, and the

composability and the automated resolution ofcontradictory policies among organizations.

W. Adjie-Winoto, E.Schwartz, H. Balakrishnan, J. Lilley, The Design and Implementation

of an Intentional Naming System, Proc. 17th ACM SOSP, Kiawah Island, SC, Dec. 1999.

So Far


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So Far

Introduction

What is the Grid? What is Grid Computing?

Wireless Grids

Motives and Driving Forces Infrastructure

Performance

Hybrid Grid Project Proposal Grid Examples

A proxy based hybrid Grid


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A proxy based hybrid Grid

Addresses:

Scalability. Integratability with current technology.

Stability

Decrease mobiles computational overhead. Hide heterogeneity.

Ease of scheduling.

Service discovery

Hybrid Grid


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Hybrid Grid

Organized mixof wireless and

wired gridnodes.

Heirachaldesign.

Proxy agentsact as mobiledevicesgateway to the

Grid.

Hybrid Grid


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Hybrid Grid

Proxy agent

Can be any device on the grid. Including a mobiledevice with appropriate middleware.

Ideally co-located with the wireless access point.

Amount of resources depend on the demand. How many mobile devices does the proxy agent serve?

Mobile devices can be invisible to the rest of thegrid.

Proxy agent will represent them to the rest of thegrid. Less responsibilities.

T. Phan, L. Huang, C. Dulan, Challenge: Integrating Mobile Wireless Devices Into the Computational Grid,

Proceedings of the 8th annual international conference on Mobile computing and networking. September 2002,pp 271-278.

Hybrid Grid


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Hybrid Grid

Within the Grid the proxy agent runs

appropriate middleware, such as Globus, topublish itself as a node.

Contribute a certain amount of computational,

networking,and storage resources. Aggregate total of the resources of the proxys active

agents.

Proxy agent handles resource requests.

E.g.: CPU Time

Hybrid Grid


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Hybrid Grid

The proxy agent decomposes the request;

Problem and data partitioning is known to be a difficult task within

the parallel computing community* Assume that a subsystem will provide the tools needed to

successfully distribute the problem

E.g.: a descriptive hint to distribute a 2-D array using blockpartitioning.

Wait for results and sends them back to the requester.

Aggregate the data before responding.

Reduce per-message overhead.

Requests for data distribution or storage are handled the same

way.

V. Kumar, A. Grama, A. Gupta, and G. Karypis. Introduction to Parallel Computing, The BenjaminCummings Publishing Company, 1994.

Hybrid Grid


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Hybrid Grid

Advantages:

Clustering technique suited for managing looselyassembled group of devices.

Similar technique used for routing in:

Bluetooth, Landmark routing, Mobile IP,ALICE, CORBA-

enabled applications.

KaZaA: peer nodes are clustered around so-called

supernodes

FastTrackJ. Haartsen. BLUETOOTH - the Universal Radio Interface for Ad-Hoc Wireless Connectivity,Ericsson Review, no. 3, 1998.G. Pei, M. Gerla, and X. Hong. LANMAR: Landmark Routing for Large Scale Wireless Ad Hoc Networks with Group Mobility, In Proceedings ofIEEE/ACM MobiHOC, August 2000.K. Truelove and A. Chasin. Morpheus Out of the Underworld, www.openp2p.com/pub/a/p2p/2001/07/02/morpheus.html

Hybrid Grid


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yb

Advantages: Proxy agent reduces communication between requestor

and each cluster node. Takes burden off each mobile device.

Scalable, because proxy agents dont have to be verypowerful and more of them can be installed as needed.

Cellular tower upgrade? Mobile devices can autonomously decide and publish their

own resources through the proxy agent.

Because user may want to choose times when they want to

give processing time to the Grid. Proxy can adjust total available resources based on its active

agent reliability.

Hybrid Grid


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Advantages: Proxy agent can cache individual requests to particular

active agents. Partially hiding connectivity deficiencies.

Results can be cached until the aggregate total is collectedif need be.

Hide heterogeneity of the mobile devices. The proxy can make scheduling decision by accessing the

power consumption metrics of the Mobile device.

Simple service discovery

Only need to locate proxy. DHCP, Jini, the Service Location Protocol, and expanding ring IP

multicast.

Example Wireless Grids


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DARC* Audio mixing application

Multilevel Triage System sensor networkpatient monitoring.

Supply Chain Asset monitoring.

Access GRID group to group interactionacross ZGRID

DARC*


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The Syracuse university research team is building asample application to demonstrate the potential.

Application allows devices with no prior knowledgeof each other collectively record and mix an audiosignal such as a concert, speech, lecture, oremergency event.

The project demonstrates the potential of wirelessgrids and distributed ad hoc resource sharing toharness the combined ability of mobile devices in

social contexts outside the expected environmentsfor

DARC* wireless grid interface


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DARC* Process Flow


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Application consists of a mixerand two ormore recorders.

1. A user wishing to initiate a recording sessionelects to act as either or both a mixer and arecorder and waits for the involvement of a

second recording service.2. Recording begins once two services have

registered with the mixer.

3. The recorders stream the recordings to the mixer.

4. The recorders then initiate a listening service toreceive the mix back from the mixer.

Multilevel Triage System Architecture


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At each site, eachemergency medical

technician has vitalsign data (such asEKG, blood oxygenlevel, and pulse) for

each patient.

The system offersedge-based control

with centralmanagement ofglobal resources.

Supply Chain Asset Monitoring


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After checking in (1), deliverytrucks are either stacked up

(2) to await being unloaded orare sent to an unloading dock(3).

As the truck is unloaded, eachitem can be sensed as it moves

into the warehouse on thecentral conveyer belt.

Items can be located within thewarehouse (4), and as they are

shipped out (5) to stores orcustomers.


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Summary


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Next generation of computing.

Incorporating mobility into Grid architecture isnecessary and beneficial to both user and

computing community.

Problems arise since meaning of performance isextended.

Encompasses many research areas.

Documents

Wireless Grid