Manet Ref01

8/12/2019 Manet Ref01

1/40

Lecture 5: Programming Mobile Ad Hoc Networks

Cristian Borcea

Department of Computer Science

NJIT

8/12/2019 Manet Ref01

2/40

Wireless systems cooperate

to achieve global tasks

2

Mobile devices dont interactwith each other directly Traditional client-server model

predominates

No interaction between mobiles

and static sensors

8/12/2019 Manet Ref01

3/40

Hard to program applications over mobile ad hoc

networks (MANETs) Systems

Mobile and distributed across physical space

Internet connectivity may be unavailable or too expensive

Resource-constrained: battery, bandwidth

May contain highly sensitive data: location, social contacts

Heterogeneous: both hardware and software

Networks Large scale

Volatile: ad hoc topologies, dynamic resources

Less secure than wired networks 3

8/12/2019 Manet Ref01

4/40

Introduction

3 MANET programming models [Ref. 1]

Migratory Services: context-aware client-service

programming

Spatial Programming: location-aware imperative

programming

Contory: SQL-like declarative programming Smart Messages: implementation platform for all 3

models

4

8/12/2019 Manet Ref01

5/40

5

Typical devices: smart phones and vehicular systems Distributed sensing services

Acquire, process, disseminate real-time information from proximityof regions, entities, or activities of interest

Have context-aware execution Many times, interact for longer period of time with clients

P

CLARKST

LAKEST

ELMWOODAVE

MAPLEAVE

RIDGE

AVE

DAVIS ST

COLLEGE ST

OLD

TOWN

P

BURNSIDE ST

P

GROVEST

OAKAV

P

P

CHURCH ST

S

C

Parking spotfinder

S

C

Traffic jampredictor

C

S

Entitytracking

8/12/2019 Manet Ref01

6/40

6

No support for context-awareness When service stops satisfying context requirements, only solution is

to discover new service

Not always possible to find new service

Overhead due to service discovery The state of the old service is lost

No support for dynamic binding of names to IP addresses Difficult to ensure that name resolution ends up with new service

when necessary No support for dynamic service deployment

Cannot guarantee that a node satisfying all context requirementshas the necessary service

End-to-end data transfers may hardly complete

8/12/2019 Manet Ref01

7/40

7

Context-awareclient-server programming model

Services migrate to nodes where they can accomplish

their tasks

Present single virtual end-point to clients One-to-one mapping between clients and services

Carry execution state across migrations

Transfer their code if necessary

Service migration Triggered by context changes

Regulated through context rules

Transparent to clients

Typically multi-hop

8/12/2019 Manet Ref01

8/408

Virtual serviceend-point

Client

n1

C

n2

n3

Context Change! (e.g., n2moves out of the region of interest)

MS cannot accomplish its task on n2any longer

ServiceMigration

MS

State MigratoryService

MSState

MigratoryService

8/12/2019 Manet Ref01

9/409

n1

C1

Meta-service

n3

M

CreateMigratory Service

MS1

State

n2 n5

MS2

State

C2MS2State

n4

MS1

State

8/12/2019 Manet Ref01

10/4010

Context

Manager Validator

Communication

Manager

Smart Messages Platform

Operating System/ Wireless Communication / Sensors

MonitoredCxt

Client Application/Service

Reliability

Manager

InCxtRules

OutCxtRules

Monitors context identifiers specified byprograms

Evaluates context rules specified by programs

IN context rules control incoming data

Used for meta-services to accept/refuse requests

Used for clients to accept/refuse responses

OUT context rules control outgoing data

Used for migratory services to decide whether to

send a response or trigger a migration

Based on the classical primary-backup approachwith two modifications

Secondary node dynamically selected in acontext-aware manner

Backup frequency constantly adapted based

on the operating network conditions

Discover meta-services

Transfer messages between

communicating end-points Carry out service migration

Provides execution migration, routing, property-basednaming

8/12/2019 Manet Ref01

11/4011

Predict traffic jams in real-time The request specifies region of interest

Service migrates to ensure it stays in this region

Uses history (service execution state) to improve prediction

TJam utilizes information that every car has: Number of one-hop neighboring cars

Speed of one-hop neighboring cars

Inform me when there is high

probability of traffic jam 10 miles ahead

8/12/2019 Manet Ref01

12/4012

monitoredCtx= {location, speed}

inCtxRule= {,

rejectResponse && sendUpdate}

serviceParameters = {region, frequency}

request = {clientName, serviceParameters}

send(TJam, request);while (NOT_DONE)

response = receive(msName);

monitoredCtx= {location, speed, region}outCtxRule= {,

migrateService}

while (NOT_DONE)

response = computeResponse();

send(clientName, response);

Client

MigratoryService

8/12/2019 Manet Ref01

13/40

Introduction

3 MANET programming models


programming

Spatial Programming: location-aware imperative

programming


models

13

8/12/2019 Manet Ref01

14/4014

Imperative programming model with fine-grained control

over individual systems

Provides a virtual name space over MANETs

Systems referencedby their locations and properties

Runtime system takes care of name resolution, reference

consistency, and networking aspects

Implementation on top of Smart Messages: SP applicationsexecute, sequentially, on each system referenced in their

code

8/12/2019 Manet Ref01

15/4015

Distributed application

Shared virtual address space

Page table + OS + Message passing

Distributed physical memory

Variable accesses

Programs access data through variables Variables mapped to physical distributed memory locations Page Table and OS guarantee reference consistency

Runtime system translates variable accesses into message passing

Access time has an (acceptable) upper bound

8/12/2019 Manet Ref01

16/40

16

radius

Hill = new Space({lat, long}, radius);

{lat,long}

Virtual representation of a physical space Similar to a virtual address space in a distributed shared

memory system Defined statically or dynamically

8/12/2019 Manet Ref01

17/40

17

{Hill:robot[0]}

{Hill:robot[1]}

{Hill:motion[0]}

Hill

r2r7

m5

Defined as {space:property} pairs Virtual names for wireless systems Similar to variables in conventional programming Indexes used to distinguish among similar systems in the

same space region

8/12/2019 Manet Ref01

18/4018

At first access, a spatial reference is mapped to asystem located in the specified space

Mappings maintained in per-application Mapping

Table (MT) similar to a page table

Subsequent accesses to the same spatial referencewill reach the same system (using MT) as long as itis located in the same space region

{space, property, index} {unique_address, location}

8/12/2019 Manet Ref01

19/40

19

Left Hill Right Hill

{Left_Hill:robot[0]}.move = ON;

r2r7

r5

{Left_Hill:robot[0]}.move = OFF;

8/12/2019 Manet Ref01

20/40

20

{Left_Hill:robot[0]}


{Right_Hill:(Left_Hill:robot[0])}

r7

8/12/2019 Manet Ref01

21/4021

Systems may move, go out of space, or disappear

Solution: associate an explicit timeout with each

spatial reference access

try{

{Hill:robot[0], timeout}.move = ON;

}catch(TimeoutException e){

// the programmer decides the next action

}

8/12/2019 Manet Ref01

22/4022

for(i=0; i Max_motion)

Max_motion = {Left_Hill:motion[i], timeout}.detect;Max_id = i;

}catch(TimeoutException e)

break;

intrusionSpace = rangeOf({Left_Hill:motion[Max_id].location}, Range);

{intrusionSpace:robot[0]}.camera = ON;{intrusionSpace:robot[0]}.focus = {Left_Hill:motion[Max_id].location};

- Find sensor thatdetected strongestmotion on Left Hill

- Turn on a camera in the

proximity of thissensor


8/12/2019 Manet Ref01

23/40

Introduction 3 MANET programming models


programming Spatial Programming: location-aware imperative

programming


models

23

8/12/2019 Manet Ref01

24/40

SensorDataSources

Resources

Monitor

SensorDataSource

SensorData

Sources

SensorDataSources

Internal

Reference 2G/3G

Reference

WiFi

Reference

Context

AggregatorContextAggregator

ContextF

actory

BT

Reference

Application

Application

Application

Event-based

commun.

MANET

commun.

MANET

commun.

OE

P

on demand queryevent-based query

periodic query

LocalCxt

Provder

O E P

LocalCxtProvider

O E PAdHocCxt

Provder

O E P

AdHocCxtProvider

O E PInfraCxt

Provder

O E P

InfraCxtProvider

O E P

Infra

Facade

AdHoc

Facade

Local

FacadeQuery

ManagerCxtQuery

Cxt

Query

Cxt

Query

SensorData

Sources

SensorDataSources

SensorData

Sources

SensorData

Sources

Declarative programmingmodel that sees MANETs asdistributed database for context (i.e., sensing) information

Flexible and adaptive context provisioning based on dynamicoperating conditions

May also query internal sensors and Internet-accessible sensors

24

MANET part

8/12/2019 Manet Ref01

25/40

SELECT FROM [(# nodes, # hops | region)]

WHERE FRESHNESS DURATION | EVERY | EVENT

SELECT temperature

FROM adHocNetwork(3, 2)

WHERE fidelity = 0.2

FRESHNESS 30 sec

DURATION 1 hour

EVENT AVG(temperature)>2525

Supports on-demand, periodic, and event-based MANETqueries

Required

Weather watcher application

8/12/2019 Manet Ref01

26/40

8/12/2019 Manet Ref01

27/40

Monitor available resources

Power, memory, running applications, etc.

Trade off sensing quality and resource consumption

Reduce the global utilization of resources

Query aggregation for queries submitted by the same

device

Prioritize tasks Context-awareness is a background activity on phones

27

8/12/2019 Manet Ref01

28/40

8/12/2019 Manet Ref01

29/40

Introduction 3 MANET programming models


programming Spatial Programming: location-aware imperative

programming


models

29

8/12/2019 Manet Ref01

30/40

30

Data migration

Lunch:

AppetizerEntreeDessert

Execution migration

8/12/2019 Manet Ref01

31/40

31

User-defined distributed applications Composed of code bricks, data bricks, and execution control state

Execute on nodes of interest named by properties (i.e., tags) Migrate between nodes of interest Self-routeat every node in the path during migrations

Network

SMPlatform

Admission

Manager

NetworkSM SM

Operating System & I/O

CodeCache

Virtual

Machine

TagSpace

SM ReadyQueue

Authorization

Cooperative node

architecture

8/12/2019 Manet Ref01

32/40

Takes place over a virtual machine

Non-preemptive, but time bounded

Ends with a migration, or terminates

During execution, SMs can Spawn new SMs

Create smaller SMs out of their code and data bricks

Access the tag space

Block on a tag to be updated (i.e., update-based

synchronization)

8/12/2019 Manet Ref01

33/40

8/12/2019 Manet Ref01

34/40

Ensures progress for all SMs in the network

Prevents SMs from migrating to nodes that cannot provide

enough resources

SMs specify lower bounds for resource requirements (e.g.,memory, bandwidth)

Determined a-priori through profiling

SMs accepted if the node can satisfy these requirements

More resources can be granted according to admissionpolicy

If not granted, SMs are allowed to migrate

8/12/2019 Manet Ref01

35/40

35

migrate(Taxi)

sys_migrate(2) sys_migrate(3) sys_migrate(4)

TaxiTaxi

1 2 3 4

migrate() multi-hop content-based migration

migrates application to node of interest named by tags

implements routing algorithm using tags and sys_migrate sys_migrate()

one hop migration

captures SM state, transfers SM to next hop, resumes SM execution

8/12/2019 Manet Ref01

36/40

36

SMs carry the routing and execute it at each node Routing information stored in tag space

SMs control their routing

Select routing algorithm (migrate primitive) Multiple library implementations

Implement a new one

Change routing algorithm during execution in response to Adverse network conditions

Applications requirements

8/12/2019 Manet Ref01

37/40

37

Network1 i

RouteToTaxi = 2 TaxiRouteToTaxi = ?RouteToTaxi = j

migrate(Taxi){

while(readTag(Taxi) == null)

if (readTag(RouteToTaxi))

sys_migrate(readTag(RouteToTaxi));

elsecreate_SM(DiscoverySM, Taxi);

createTag(RouteToTaxi, lifetime, null);

block_SM(RouteToTaxi, timeout);

}

2

8/12/2019 Manet Ref01

38/40

Implemented in Java

Java 2 Micro-Edition (J2ME) with CLDC 1.1 and MIDP 2.0

J2ME with CDC

Development using HP iPAQs (Linux) and Nokia phones

(Symbian)

SM platforms

Original SM on modified KVM (HP iPAQs) migration state captured

in the VM

Portable SM on Java VM, J2ME CDC (Nokia 9500) migration state

captured using bytecode instrumentation

38

8/12/2019 Manet Ref01

39/40

1. Urbanets

http://cs.njit.edu/~borcea/papers/ieee-pervasive07.pdf

2. Migratory Services

http://cs.njit.edu/~borcea/papers/ieee-tmc07.pdf

3. Spatial Programming

http://cs.njit.edu/~borcea/papers/spsm04.pdf

4. Contory http://people.inf.ethz.ch/oriva/pubs/riva_middleware06_paper.pdf

5. Smart Messages

http://cs.njit.edu/~borcea/papers/sm03.pdf 39
http://cs.njit.edu/~borcea/papers/ieee-pervasive07.pdfhttp://cs.njit.edu/~borcea/papers/ieee-tmc07.pdfhttp://cs.njit.edu/~borcea/papers/spsm04.pdfhttp://people.inf.ethz.ch/oriva/pubs/riva_middleware06_paper.pdfhttp://cs.njit.edu/~borcea/papers/sm03.pdfhttp://cs.njit.edu/~borcea/papers/sm03.pdfhttp://people.inf.ethz.ch/oriva/pubs/riva_middleware06_paper.pdfhttp://cs.njit.edu/~borcea/papers/spsm04.pdfhttp://cs.njit.edu/~borcea/papers/spsm04.pdfhttp://cs.njit.edu/~borcea/papers/spsm04.pdfhttp://cs.njit.edu/~borcea/papers/ieee-tmc07.pdfhttp://cs.njit.edu/~borcea/papers/ieee-tmc07.pdfhttp://cs.njit.edu/~borcea/papers/ieee-tmc07.pdfhttp://cs.njit.edu/~borcea/papers/ieee-pervasive07.pdfhttp://cs.njit.edu/~borcea/papers/ieee-pervasive07.pdfhttp://cs.njit.edu/~borcea/papers/ieee-pervasive07.pdfhttp://cs.njit.edu/~borcea/papers/ieee-pervasive07.pdfhttp://cs.njit.edu/~borcea/papers/ieee-pervasive07.pdf

8/12/2019 Manet Ref01

40/40

1. Two decades of mobile computing

2. Infrastructure support for mobility

3. Mobile social computing

4. People-centric sensing5. Programming mobile ad hoc networks

6. Vehicular computing and networking

Vehicular ad hoc network (VANET) applications: EzCab & TrafficView

RBVT routing in VANET

Dynamic traffic guidance in vehicular networks

7. Privacy and security in mobile computing

Manet Ref01

Documents

Transcript of Manet Ref01