Chapter 13: Routing Protocols in Infrastructure- less Opportunistic Networks

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Nov 21, 2013 (3 years and 6 months ago)

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Chapter 13:

Routing
Protocols in Infrastructure
-
less Opportunistic
Networks


Sanjay Kumar Dhurandher
1
, Deepak Kumar Sharma
2
, Isaac
Woungang
3
,and
Shruti

Bhati
1


1
University of Delhi

2
University of Delhi

3

Ryerson University

R
OUTING

IN

O
PPORTUNISTIC

N
ETWORKS

Opportunistic Networks(OppNets)

Characteristics & Challenges


Opportunistic

Network

[
1
]

is

one

of

the

most

interesting

and

recent

evolutions

of

Mobile

Ad
-
hoc

Networks

(MANETs)
.


The

traditional

routing

algorithms

used

for

MANETs

and

Internet

are

not

applicable

here

as

they

first

establish

a

path

between

the

source

and

the

destination

before

the

actual

message

transfer

which

is

not

possible

in

case

of

OppNets

[
2
,
3
]
.


They

exhibit

a

store
-
carry

and

forward

approach
.

If

a

suitable

node

is

not

found,

the

node

simply

stores

the

message

and

carries

it

through

the

network

until

a

better

node

or

destination

is

found

[
4
,
5
]
.


Opportunistic Networks(OppNets)

Characteristics & Challenges (Contd.)


OppNets

are enabled to deliver messages even when
there is no connected path between the source and
the destination.


One

key

characteristic

of

opportunistic

networks

is

that

they

are

essentially

delay

tolerant

in

nature

as

they

can

handle

large

delays

in

message

delivery

from

the

source

to

the

destination
.



OppNets

share

similar

routing

algorithms

as

used

in

Delay

Tolerant

Networks

[
6
,
7
]
.


If

a

suitable

node

is

not

found,

the

node

simply

stores

the

message

and

carries

it

through

the

network

until

a

better

node

or

destination

is

found

[
5
]
.



Types of protocols for routing in
OppNets


The

routing

protocols

in

OppNets

are

divided

into

two

categories

namely

the

infrastructure

based

and

the

infrastructure
-
less

protocols

[
8
]


Infrastructure

based

protocols
:

These

protocols

make

use

of

some

form

of

infrastructure

to

opportunistically

forward

messages
.



Base

stations

and

access

points

are

often

involved

in

the

routing

and

forwarding

of

the

messages
.



Infrastructure
-
less

protocols
:

These

protocols

are

best

suited

for

the

flat

ad
-
hoc

networks
.



They

only

make

use

of

the

mobility

of

the

nodes

and

the

contact

opportunity

between

them

in

order

to

route

the

messages
.



They

make

no

previous

assumptions

about

the

network

topology

and

all

the

nodes

behave

same

in

the

network

and

are

given

the

same

priority



OppNets

Routing Protocols

Direct Transmission [9]:


The

source

node

does

not

forward

the

message

to

the

intermediate

nodes,

but

stores

it

in

the

buffer

until

it

comes

in

direct

contact

with

the

destination

node
.



On

encountering

the

destination

node,

the

message

is

directly

given

to

the

destination
.


Advantages



This

protocol

utilizes

minimum

network

resources,

and

cannot

suffer

from

the

problems

of

network

clogging
.


The

protocol

is

very

simple

and

fairly

easy

to

deploy
.


Disadvantages


It

is

likely

to

suffer

from

heavy

delays

as

source

node

may

not

encounter

the

destination

node

for

longer

period

of

times
.


If

a

node

failure

occurs,

the

message

can

be

lost

since

there

is

only

one

cope

available

in

the

network
.


Example scenario of Direct Transmission

OppNets

Routing Protocols (Contd.)

First

Contact

[
10
]
:


It

is

a

routing

scheme[
10
]

that

does

not

predict,

utilize

or

assume

any

properties

of

the

network

or

the

nodes
.



The

carrier

node

forwards

the

message

to

any

node

that

comes

into

contact

with

it
.


Advantages



It

does

not

make

any

assumptions

about

the

network

and

thus

can

be

implemented

easily
.


This

scheme

can

be

used

for

multicast

messages
.


Disadvantages



The

scheme

can

lead

to

huge

message

delivery

delays
.


Indiscriminate

spreading

of

messaging

can

lead

to

network

clogging

as

well

as

packet

dropping

which

are

highly

unacceptable

Example Scenario of First Contact

OppNets

Routing Protocols (Contd.)

Epidemic

Protocol

[
11
]
:


This

protocol

[
11
]

makes

minimal

assumptions

about

the

network

and

is

guaranteed

to

deliver

the

message

to

the

destination
.



It

aims

to

distribute

messages

to

other

nodes

within

connected

portions

of

the

network
.



These

nodes

then

come

into

contact

with

another

portion

of

the

network

and

the

message

spreads

like

a

disease

(epidemic)
.



Advantages




The

protocol

makes

minimum

assumptions

about

the

network

topology

and

it

is

fairly

easy

to

deploy

and

understand
.


Out

of

all

the

opportunistic

network

protocols,

epidemic

has

the

least

overhead

in

terms

of

calculations

for

determining

the

next

hop
.


The

message

delivery

probability

is

very

high

in

this

protocol
.

OppNets

Routing Protocols (Contd.)

Epidemic

Protocol

[
11
]
:



Disadvantages


The

memory

and

resource

consumption

is

very

high

in

this

protocol,

as

the

message

is

passed

to

all

the

nodes

indiscriminately
.


Considerable

amount

of

computation

occurs

at

every

node

before

exchanging

the

messages

even

in

the

case

of

nodes

that

might

have

the

same

messages
.

Hence

some

amount

of

memory

is

wasted
.


Even

when

a

message

is

received

at

the

destination,

some

nodes

still

continue

passing

on

the

messages

which

wastes

resources
.

Example Scenario of Epidemic Routing

OppNets

Routing Protocols (Contd.)

Spray

and

wait

[
12
]
:


This

protocol[
12
]

is

an

extension

to

the

epidemic

routing

protocol
.



It

aims

to

reduce

the

overhead

of

flooding

which

often

causes

network

congestions

and

indiscriminate

usage

of

the

network

resources
.



One

way

of

doing

so

is

to

only

forward

a

copy

with

some

probability
.



The

probability

is

the

utility

of

every

node

based

on

the

timer

indicating

the

time

elapsed

since

the

two

nodes

last

encountered

the

node

maintaining

the

record
.

These

are

indirectly

the

relative

node

locations


There

are

two

phases

in

the

forwarding

process





Spray

phase



Every

message

generated

is

spread

randomly

to

L

relay

nodes

i
.
e
.

L

copies

of

message

are

created
.


Wait

phase



If

the

destination

is

not

found

in

spray

phase,

the

nodes

then

wait

for

direct

transmission
.

OppNets

Routing Protocols (Contd.)


Binary

Spray

and

Wait



It

is

a

variation

of

the

spray

and

wait

protocol
.

The

source

starts

initially

with

L

copies

of

the

message
.



The

source

or

any

relay

node

that

has

n>
1

message

copies

hands

over


n/
2


copies

to

any

other

node

(without

message

copy)

in

the

network

and

keeps

the

remaining

copies


n/
2


with

itself
.


Advantages



The

protocol

reduces

the

memory

inefficiencies

of

epidemic

routing

by

limiting

the

amount

of

flooding

caused

in

the

network
.


Disadvantages



Even

though

L

is

chosen

to

limit

flooding,

the

protocol

still

suffers

from

delays

and

resource

consumption

issues
.


The

message

delivery

probability

depends

highly

on

the

value

of

L

chosen,

which

is

assumed

on

the

basis

of

the

network

parameters
.

Example Scenario of Spray and Wait

OppNets

Routing Protocols (Contd.)

Spray

and

Focus

[
13
]
:


This

protocol

[
13
]

overcomes

the

shortcomings

of

simple

spraying

algorithms

and

is

better

than

the

flooding
.


The

scheme

again

has

two

phases





Spray

phase



When

a

new

message

is

generated

at

the

source

node,

it

creates

L

forwarding

tokens

for

this

message
.



When

a

node

meets

another

node

with

no

message

copy,

the

first

node

copies

the

message

to

the

second

node

along

with

n/
2

forwarding

tokens
.



When

a

node

has

only

one

forwarding

token

then

it

forwards

the

message

according

to

the

Focus

phase
.



Focus

phase


Forwarding

is

done

based

on

some

criterion
.

These

decisions

are

based

on

a

set

of

timers

that

record

the

time

since

the

two

nodes

last

saw

each

other
.

Node

i

maintains

a

timer

T
i
(j)

for

every

other

node

j

which

records

time

elapsed

since

the

two

nodes

last

saw

each

other
.


OppNets

Routing Protocols (Contd.)

Spray

and

Focus

[
13
]
:



Advantages



Owing

to

refined

selection

criterion,

the

protocol

has

higher

message

delivery

rates
.


Fewer

copies

are

spread

into

the

network

as

compared

to

the

spray

and

wait

protocol
.


Disadvantages



The

protocol

suffers

from

a

larger

overhead

of

resource

consumption
.


Protocol

suffers

in

case

of

sparse

networks

as

the

time

taken

by

nodes

to

meet

will

be

greater

and

there

will

be

fewer

opportunities

to

forward

the

data
.

OppNets

Routing Protocols (Contd.)

Adaptive

Fuzzy

Spray

and

Wait

[
14
]
:



This

protocol

[
14
]

has

been

proposed

as

an

improvement

over

the

popular

spray

based

routing

schemes
.



It

smartly

integrates

the

overheads

and

buffer

management

policies

into

an

adaptive

protocol

that

includes

local

network

parameters

estimation
.



The

algorithm

can

be

summarized

in

the

following

few

steps
:


The

node

on

encountering

other

nodes

divides

the

values

of

L

by

2

and

updates

it

in

the

message

before

passing

it

on
.


The

node

passes

on

all

the

copies

to

the

nodes

it

encounters

except

the

last

copy

which

is

passed

on

as

direct

transmission
.


The

messages

in

the

buffer

are

sorted

by

a

priority

decided

by

a

Fuzzy

decision

making

function
.


When

the

buffer

is

full,

the

messages

are

dropped

according

to

the

priority

level

i
.
e
.

the

oldest

first
.

OppNets

Routing Protocols (Contd.)

Adaptive

Fuzzy

Spray

and

Wait

[
14
]
:



Forward

Transmission

Count

and

Message

Size

are

two

indicators

that

help

in

determining

the

prioritization

quantity
.

The

dropping

policy

used

for

the

algorithm

is

random

instead

of

drop

least

priority

scheme

so

that

it

remains

fair

to

all

the

messages
.


Advantages



The

scheme

has

better

delivery

performance

than

simple

spray

based

techniques
.


Appropriate

and

fair

buffer

management

schemes

used

in

this

protocol

avoid

the

clogging

of

the

network
.


Disadvantages



Large

messages

might

get

delayed

if

there

are

a

higher

number

of

small

messages
.


If

all

the

messages

are

of

approximately

the

same

size

and

a

constant

indicator

of

size

is

used,

the

size

of

message

becomes

irrelevant

to

priority

OppNets

Routing Protocols (Contd.)

PRoPHET

[
15
]
:



Probabilistic

Routing

Protocol[
15
]

using

History

of

Encounters

and

Transitivity

(
PRoPHET
)

,

assumes

that

instead

of

moving

randomly

the

nodes

in

a

network

move

in

a

predictable

fashion

wherein

patterns

are

likely

to

repeat

themselves
.



This

information

can

be

used

to

improve

the

routing

performance
.


Each

node

before

sending

a

message,

calculates

a

probabilistic

metric

called

Delivery

Predictability

for

each

known

destination

in

form

of

vectors
.



This

Delivery

Predictability

is

assumed

to

be

P(
a,b
)


{
0
,
1
}

i
.
e
.

the

probability

of

every

node

a

to

meet

any

other

node

b

in

the

network
.

OppNets

Routing Protocols (Contd.)

PRoPHET

[
15
]
:



Advantages



Simulation

results

of

this

protocol

show

that

it

has

less

message

exchanges,

less

communication

overhead,

less

delay,

and

higher

delivery

success

rate

as

compared

to

the

epidemic

routing
.



The

protocol

is

highly

suited

to

human

mobility

scenarios
.


Disadvantages



Resource

consumption

occurs

in

terms

of

calculations

occurring

at

each

node
.


Memory

is

needed

to

store

the

probability

tables

generated

by

the

protocol
.


Packets

may

be

dropped

consistently

when

forwarded

to

a

few

concentrated

nodes

due

to

FIFO

queuing

nature

of

PRoPHET
.

OppNets

Routing Protocols (Contd.)

PRoPHET
+

[
16
]
:



This

protocol

[
16
]

is

an

extension

to

the

PRoPHET

protocol

that

uses

only

delivery

predictabilities

of

the

nodes

to

decide

the

next

best

carrier

for

the

message
.



This

scheme

uses

several

other

parameters

such

as

Buffer
,

Power
,

Bandwidth
,

Location

and

Popularity

into

consideration

to

reduce

the

packet

loss

and

transmission

delay
.


Advantages



Packet

dropping

and

loss

are

significantly

reduced

as

compared

to

PRoPHET

by

monitoring

the

power

and

popularity

of

the

node
.


The

protocol

takes

into

account

several

parameters

other

than

delivery

predictability

which

strengthens

the

best

node

probability
.


Disadvantages



Too

many

calculations

need

to

be

done

at

each

node
.


Uncooperative

nodes

can

cause

a

problem

for

the

sender

OppNets

Routing Protocols (Contd.)

HiBOp

[
17
]
:



The

History

Based

Routing

Protocol

for

Opportunistic

Networks

(
HiBOp
)

[
17
]

aims

at

effectively

utilizing

the

context

information

of

the

node

in

order

to

decrease

the

overhead

of

flooding
.



The

Current

Context

(CC)

of

a

user

is

a

snapshot

of

the

local

environment

of

the

user
.



It

is

stored

in

the

form

of

Identity

Tables

(ITs)
.



Every

node

also

stores

a

History

table

that

stores

values

from

the

ITs

seen

by

the

node

in

the

past
.



Every

value

has

a

Continuity

Probability

(P
c
),

Heterogeneity

(H)

and

Redundancy

(R)

counters

associated

with

them
.


OppNets

Routing Protocols (Contd.)

HiBOp

[
17
]
:



The

forwarding

process

in

HiBOp

is

made

of

three

phases
:


Emission

Phase
:

HiBOp

injects

the

message

into

the

network

through

flooding

to

an

appropriate

number

of

nodes

by

creating

message

replicas

for

reliability
.



The

number

of

neighbors

(
K
)

to

which

the

message

is

forwarded

by

the

sender

is

calculated

using

a

formula

that

takes

into

account

the

probability

of

delivering

the

message

to

the

destination
.



The

value

of

K

should

be

minimized

in

order

to

minimize

the

joint

loss

probability

below

a

certain

threshold
.



Forwarding

Phase
:

It

uses

the

node’s

mobility

and

contacts

to

take

the

message

closer

to

the

destination
.



It

uses

two

quantities

.
The

forwarding

of

message

to

a

certain

node

during

its

journey

in

the

network

is

determined

by

the

match

between

the

sender

information

and

the

context

information

of

the

nodes
.



Delivery

predictability

of

a

node

is

also

taken

into

account

before

passing

on

the

message
.

At

each

node

the

delivery

probability

is

calculated

using

node

IT,

its

CC

and

its

History

table
.

OppNets

Routing Protocols (Contd.)

HiBOp

[
17
]
:



Delivery

Phase
:

When

an

intermediate

node

finds

the

destination,

the

message

is

delivered

to

it

and

the

process

stops
.


Advantages



This

protocol

stores

the

largest

amount

of

context

information

among

all

context

base

protocols,

so

it

can

fully

exploit

the

advantages

of

context

information
.


The

protocol

is

very

suitable

for

human

mobility

models

that

generally

follow

a

particular

pattern
.


The

protocol

reduces

network

clogging

by

drastically

limiting

the

number

of

copies

spread

in

the

network
.


Disadvantages



The

IT
,

CC
,

History

table

and

Repository

table

require

a

large

amount

of

memory

space

on

every

node
.


The

calculations

done

every

time

at

every

node

can

significantly

reduce

the

amount

of

time

left

for

message

exchange
.


OppNets

Routing Protocols (Contd.)

CEPMF

[
18
]
:



This

protocol

[
18
]

uses

the

content

of

the

messages

to

relay

and

deliver

them

to

their

destination
.



The

node

that

generates

the

messages

is

called

the

publisher

and

the

node

that

wants

a

message

similar

in

content

to

the

message

being

sent

is

called

subscriber
.


If

subscribers

demand

a

message

of

a

particular

type

of

content,

they

spray

the

network

with

their

interests

all

over

the

network

in

the

form

of

predicates
.


The

entire

protocol

can

be

divided

into

two

steps
-


Predicate

propagation
:

The

subscriber

spreads

its

interests

into

the

network

by

spraying

predicates
.

The

Spray

and

Wait

scheme

is

used

for

sending

the

predicates
.


Message

Forwarding
:

Each

node

has

a

table

carrying

the

message

and

tagged

to

it

ep

value
.

At

source

node

the

value

is

zero
.



When

a

node

transfers

message

to

a

node

carrying

the

message’s

ep

value

in

its

table,

the

acknowledgement

tells

the

source

to

stop

sending

until

it

is

out

of

its

range
.



OppNets

Routing Protocols (Contd.)

CEPMF

[
18
]
:



Advantages



The

protocol

can

be

safely

used

for

multicast

messaging

situations
.


It

does

not

rely

on

the

geographic

location

of

the

nodes

and

thus

can

be

used

in

cases

where

GPS

is

not

enabled
.


Disadvantages



A

node

may

still

receive

a

particular

message

which

it

does

not

want,

if

its

demands

are

partially

similar

to

the

predicates

of

the

message
.


There

might

be

high

privacy

and

rick

issues

associated

with

the

content

transparency
.



Example Scenario of CEPMF

OppNets

Routing Protocols (Contd.)

Robust

Proactive

Routing

Protocol

[
19
]
:



This

protocol[
19
]

has

been

proposed

as

a

proactive

scheme

to

deliver

messages

in

the

highly

disconnected

scenarios

present

in

OppNets
.



It

is

an

adaptive

protocol

that

uses

the

opportune

contacts

between

the

nodes

to

determine

the

neighborhood

information

for

each

node

and

use

that

to

deliver

the

messages
.


The

basic

principle

is

that

a

node

can

determine

the

predictability

information

and

connectedness

information

using

past

history
.



The

nodes

do

not

forward

data

randomly

instead

they

have

a

well

studied

and

selected

next

hop

node
.



OppNets

Routing Protocols (Contd.)

Robust

Proactive

Routing

Protocol

[
19
]
:



Advantages


The

following

protocol

is

suited

to

Human

mobility

models

since

it

can

show

better

results

for

predictable

movement
.


It

reduces

the

overhead

of

flooding

by

limiting

the

next

hop

for

node

and

only

selects

the

best

candidate
.


Disadvantages


There

is

considerable

overhead

in

exchanging

and

storing

tables

at

each

node
.


OppNets

Routing Protocols (Contd.)

Repository

Based

Forwarding

Protocol

[
20
]
:



This

protocol

[
20
]

makes

distinction

between

the

types

of

nodes

in

the

network

and

uses

them

to

deliver

the

message

to

its

destination
.



It

argues

that

assuming

all

nodes

to

be

Mobile

Nodes

is

not

correct

in

a

model

where

nodes

move

in

a

predictable

fashion

(Human

mobility

model)
.



Some

nodes

are

likely

to

be

in

a

place

more

often

than

others
.

Hence

commonly

visited

and

shared

location

are

assigned

to

be

Fixed

Nodes
.


The

Mobile

Nodes

are

characterized

by

the

mobility

pattern

which

in

turn

has

a

strong

impact

on

their

performance
.



Each

node

has

a

character

table

(CT)

that

defines

the

node’s

home

location,

communication

range,

ID

and

type
.


OppNets

Routing Protocols (Contd.)

Repository

Based

Forwarding

Protocol

[
20
]
:



When

a

node

meets

another

node,

they

exchange

their

CT

tables

that

describe

their

characteristics
.



Depending

on

the

type

one

of

the

nodes

initiates

the

forwarding

process
.

The

forwarding

process

is

further

divided

into

two

parts
:


Message

Dispatch
:

Node

initiating

communication

sends

all

messages

as

type

tsend

either

directly

(to

the

target

node

itself)

or

indirectly

(i
.
e
.

through

a

Fixed

Node

which

eventually

forwards

it)
.


Message

Collect
:

Node

collects

all

the

messages

that

have

the

target_ID

set

as

the

node

itself
.

The

status

flag

is

checked

to

prevent

from

the

same

message

being

collected

again


Advantages




Fixed

nodes

can

decrease

the

delivery

delays

considerably
.


Disadvantages



If

fixed

nodes

fail,

the

entire

network

will

be

brought

down


OppNets

Routing Protocols (Contd.)

MaxProp

[
21
]
:



This

protocol

[
21
]

assumes

that

it

has

no

prior

knowledge

about

the

network

connectivity

and

uses

the

local

information

and

opportune

movement

to

select

the

next

best

hop

for

the

message

delivery
.



The

protocol

has

three

main

components

:



Estimating

Delivery

Likelihood
:

The

protocol

aims

to

find

the

optimal

delivery

paths

by

constructing

a

directed

graph

of

nodes

which

are

connected

by

edges

[
21
]
.



A

variation

of

Dijkstra’s

algorithm

is

used

to

determine

the

shortest

path

out

of

available

paths

at

any

given

point

of

time
.


Complementary

Mechanisms
:

This

step

describes

the

priority

order

in

which

messages

are

exchanged

when

two

nodes

discover

each

other
.


Managing

Buffer
:

The

protocol

states

that

there

is

a

difference

between

managing

limited

storage

and

limited

transmission

in

that

the

packets

sent

once

can

be

sent

again
.


OppNets

Routing Protocols (Contd.)

MaxProp

[
21
]
:



Advantages


MaxProp

uses

Dijkstra’s

algorithm

to

ensure

that

the

lowest

cost

path

is

chosen

so

as

to

decreases

the

delivery

latency
.


Proper

buffer

management

schemes

lead

to

a

lowered

rate

of

packet

dropping
.


Disadvantages



The

overhead

of

table

exchange

can

decrease

the

effective

time

for

message

exchange
.


The

protocol

is

not

suited

for

sparse

networks,

as

it

will

not

give

a

proper

connected

graph

and

thus

will

not

satisfy

the

protocol

criteria
.


OppNets

Routing Protocols (Contd.)

CAR

[
22
]
:



In

this

protocol[
22
]

,

the

nodes

are

assumed

to

rely

on

their

‘logical

connectivity

information’

with

other

nodes
.



They

are

not

aware

about

the

location

of

the

nodes,

which

are

the

recipients

of

the

messages

they

are

carrying

with

them
.



Proactive

protocol

such

as

DSDV

[
25
]

is

used

to

deliver

the

messages

if

the

recipient

node

belongs

in

the

same

cloud
.



Otherwise,

the

relay

nodes

are

chosen

in

such

a

manner

that

they

present

the

highest

delivery

probabilities
.


The

process

of

prediction

and

evaluation

of

context

takes

care

of

following

things
.


Calculation

of

self

delivery

probabilities


T
able


Local

prediction

of

delivery

probabilities

at

intervals


New

message

recipient


Message

exchange

OppNets

Routing Protocols (Contd.)

CAR

[
22
]
:



Advantages


The

protocol

is

uninfluenced

by

the

unavailability

of

GPS
.


The

proactive

approach

highly

reduces

the

overhead

of

prediction

calculation

and

can

deliver

message

faster

if

dense

networks

are

present
.


Disadvantages


The

overhead

of

table

exchange,

updating

and

maintenance

can

severely

reduce

the

performance
.


In

absence

of

a

proper

buffer

management

scheme,

the

messages

may

be

lost
.


OppNets

Routing Protocols (Contd.)

Meetings

and

Visits

[
23
]
:



This

routing

protocol

[
23
]

uses

the

same

pair
-
wise

message

exchange

principle

as

Epidemic

Routing
,

but

improves

on

the

method

used

to

determine

which

messages

to

transmit
.



Instead

of

flooding

its

neighbors,

each

node

uses

observation

data

on

the

meetings

between

nodes

and

visits

to

locations

(hence

the

name

MV
)

to

compute

a

delivery

probability

for

every

other

node
.


When

two

nodes

meet,

the

summary

vectors

contain

not

only

the

message

identifiers

but

also

the

computed

delivery

probability
.



Nodes

compare

their

own

and

their

pair’s

values,

and

only

request

messages

for

which

their

probability

is

higher
.


OppNets

Routing Protocols (Contd.)

Meetings

and

Visits

[
23
]
:



Advantages


The

protocol

is

highly

suited

to

human

mobility

scenarios

as

mobility

patterns

of

nodes

are

stored

for

routing

of

the

messages
.



It

uses

the

techniques

from

robotic

control

to

obtain

high
-
quality

approximations

for

the

optimal

solution
.


It

also

limits

the

number

of

hops

that

are

required,

by

calculating

an

estimation

of

delivery

likelihood

assuming

an

infinite

buffer

at

each

peer
.


Disadvantages


As

it

uses

FIFO

for

buffer

management

at

nodes,

packets

may

get

dropped

consistently

when

forwarded

to

a

concentrated

node
.


Considerable

overhead

occurs

in

storing

the

mobility

pattern

of

nodes

at

regular

time

intervals
.


OppNets

Routing Protocols (Contd.)

Network

Coding

[
24
]
:



This

protocol[
24
]

presents

an

approach

in

which

a

message

is

encoded

into

another

format

before

transmission
.



The

intermediate

nodes

not

only

forward

but

also

can

combine

packets

using

a

given

invertible

function

before

forwarding

to

limit

the

message

flooding
.



At

the

receiver

side,

as

compared

to

the

replication

based

schemes

which

rely

on

successful

delivery

of

each

individual

data

block,

this

scheme

consider

the

successful

delivery

of

a

block

only

when

the

necessary

number

of

blocks

is

received

to

reconstruct

the

original

data
.


OppNets

Routing Protocols (Contd.)

Network

Coding

[
24
]
:



Advantages


This

schemes

is

more

robust

against

packet

losses

than

replication

based

schemes

when

network

connectivity

is

extremely

poor,

as

it

consider

the

successful

delivery

of

a

block

only

when

the

necessary

number

of

blocks

is

received

to

reconstruct

the

original

data
.


The

number

of

transmissions

is

reduced

in

this

approach,

and

consequently

the

packet

delivery

ratio

is

much

higher

than

the

probabilistic

forwarding

both

in

dense

mobile

networks

and

sparse

networks
.


Disadvantages


When

the

network

is

well

connected

this

schemes

is

less

efficient

due

to

additional

information

embedded

in

the

code

blocks
.


This

method

leads

to

additional

processing

power

and

memory

requirements

due

to

the

encoding

and

decoding

process
.

Tabular Comparison of various protocols

Protocol

Algorithm

Assumptions

Simulation Model

Number of
Message
copies


Next hop
selection method

Drawbacks

DeliveryDe
lay

Delivery
Ack

Buffer Size
Available

BandwidthCap
acity

Simulator
Used

Mobility
Model Used

Direct Trans
-
mission [9]

Single

The destination
of the message
itself

High Delays and
low delivery
latency

High

None

Limited

Not Men
-
tioned

Custom
discrete event
driven

Random
Waypoint
(RWP) [27]

First Contact
[10]

Single

The next node
encountered

High amount of
clogging in the
network

High due
to path
loops

None

Not men
-
tioned

Not men
-
tioned

Own for DTN
environment
[28]

Own Remote
village city
bus N/W

Epidemic
Routing [11]

Un
-

limited

Flooding

High resource
(bandwidth,
buffer) usage

Low

Not men
-
tioned

Limited

Not men
-
tioned

Monarch[29]

RWP

Spray and
Wait [12]

Limited (L)

Randomness

Random
decision
making

Medium

Not men
-
tioned

Sufficient

Sufficient

Own

RWP,
RD,RW

Spray and
Focus [13]

Limited (L)

Timer based
probabilities
calculation

High resource
consumption

Medium

Not men
-
tioned

Sufficient

Sufficient

Own

RWP, Random
Walk(RW)

Adaptive
Spray and
Wait [14]

Limited

Flooding

Distinction
made in size of
messages

Medium

Not men
-
tioned

Limited.
Buffer man
-
agement

used
extensively

Sufficient

ONE[30]

RWP

Tabular Comparison of various protocols
(contd.)

Protocol

Algorithm

Assumptions

Simulation Model

Number of
Message
copies


Next hop
selection method

Drawbacks

DeliveryDe
lay

Delivery
Ack

Buffer Size
Available

BandwidthCap
acity

Simulator
Used

Mobility
Model Used

PRoPHET

[15]

Single

Probability
obtained from
previous meetings

Too much
calculation
overhead at
each node

Medium

Not
mentioned

Limited

Not men
-
tioned

Own

Own

PRoPHET+
[16]

Single

Probability of
previous meetings,
buffer, power,
bandwidth and
popularity
parameters

Un
-
cooperative
nodes can cause
security &
forwarding
problems

Medium

Not men
-
tioned

Limited.
Managed
extensively

Sufficient and
evaluated
before
transferring
message

DTNSIM [31]

iMote trace
[32]

HiBOp [17]

Single

Identity tables
and history table
used to find
context of nodes

High overhead
of storing
tables

Medium

Not men
-
tioned

Limited and
managed

Assumed
infinite

Own

Community
Based (CB)

CEMPF [18]

Limited
Flooding

Content of the
message and
predicates

Privacy and risk
issues

High as
content of
messages
are
matched

Relay to
relay as well
as source to
destination
ack used

Limited

Sufficient

OMNET++
[33]

A hybrid of
RWP and CB

Robust
Proactive
Routing
Protocol [19]

Single

Predictability and
connected
-
ness
information

Overhead of
exchanging,
storing and
updating tables

Medium

Not men
-
tioned

Limited

Sufficient

Jist/SWANS
[34]

Not
mentioned

RFP [20]

Single

Type of node

Failure of fixed
nodes

Medium

Used

Limited

Sufficient

Own

Human
Mobility
Model

Tabular Comparison of various protocols
(contd.)

Protocol

Algorithm

Assumptions

Simulation Model

Number of
Message
copies


Next hop
selection
method

Drawbacks

DeliveryD
elay

Delivery
Ack

Buffer
Size
Available

BandwidthCa
pacity

Simulator
Used

Mobility
Model Used

MaxProp
[21]

Single

Previous node
meetings and
finding best
path using
likelihood of
meetings

In case of
sparse
network the
no of
available
paths might
decrease
drastically

Medium

Used

Unlimited
(own)
Limited
(others).
Buffer
manage
-

ment

Used

Sufficient

Own

Synthetic
models of
real data

CAR [22]

Single

DSDV and
Delivery
probability
using context
information

Overhead of
table
management
and exchange

Medium

Not men
-
tioned

Sufficient

Sufficient

OMNET++
[33]

Own Group
based
mobility
model [35]

MV

Routing [23]

Single


Probability of
visiting the
region of the

destination

Overhead in
storing the
mobility
pattern of a
node at reg
-

ular intervals

Medium
more than
Epidemic

Not men
-
tioned

Unlimited
(own)
Limited
(others).
managed by
FIFO.

Sufficient

NS
-
2[36]

Synthetic
traces of
node move
-
ment in
geographica
rea

Network

Coding [24]

Limited

Flooding to the
neighbors

Overhead in
encoding and
decoding of
message and
reassembling
at destination

Not Men
-

tioned

Not men
-
tioned

Not men
-
tioned

Not men
-
tioned

Own (custom
time based
simulator)

RWP

Conclusion


In

this

chapter,

we

have

given

a

brief

outline

of

a

number

of

routing

protocols

for

infrastructure
-
less

OppNets
.



These

protocols

have

been

analyzed

and

compared

on

the

basis

of

their

advantages

and

disadvantages

with

respect

to

a

variety

of

parameters
.


This

study

leads

to

the

identification

of

some

critical

and

explicit

characteristics

of

each

protocol

along

with

their

areas

of

application
.



A

few

main

concerns

that

are

reflected

in

almost

all

protocols

are

delivery

latency,

packet

dropping

and

packet

loss,

memory

management,

computation

and

storage

overhead
.



The

discussed

protocols

in

this

chapter

implement

different

techniques

to

abate

the

inefficiencies

caused

due

to

these

factors
.

References

[1] L.
Lilien
, Z.H.
Kamal
, V.
Bhuse
, and A. Gupta, “Opportunistic Networks: The Concept and Research Challenges in Privacy and Security,”
in
Proceedings Of NSF Intl. Workshop on Research Challenges in Security and Privacy for Mobile and Wireless Networks (WSPWN 2006
)
, Miami,
March 2006, pp. 134
-
147.

[2] Charles E. Perkins and Elizabeth 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, February 1999, pp. 90
-
100.


[3] L
-
J. Chen, C. Hung Yu, C. Tseng, H. Chu, and C. Chou, “A Content
-
Centric Framework for effective Data Dissemination in Oppo
rtunistic networks”,
IEEE Journal on selected Areas in Communications
,
vol
: 26, Issue: 5, June 2008, pp. 761
-
772.

[4] C.
-
M. Huang, K.
-
C.
Lan
, C.
-
Z, and Tsai, “A survey of opportunistic networks”,
in proceedings of the 22
nd
Intl. Conference on Advanced Information
Networking and Applications
-

workshops, 2008 (AINAW 2008)
, Okinawa, Japan, 25
-
28 March, 2008, pp. 1672
-
1677.

[5] S. K.
Dhurandher
, D. K. Sharma, I.
Woungang
, and H.C. Chao, “Performance Evaluation of Various Routing Protocols in Opportunistic Networks”,
in
Proceedings of IEEE GLOBECOM Workshop 2011
, Houston, Texas, USA , 5
-
9 December, 2011, pp. 1067
-
1071.

[6] K. Fall, “A Delay
-
Tolerant Network Architecture for Challenged Internets”,
in proceedings of ACM SIGCOMM 2003
, Karlsruhe, Germany, 25
-
29
August, 2003, pp. 27
-
34.

[7] Z. Zhang, “Routing in Intermittently Connected Mobile Ad Hoc Networks and Delay Tolerant Networks: Overview and Challenge
s”,

IEEE
Communications Surveys and Tutorials
,
Vol
: 8, Issue: 1, 2006, pp. 24
-
37.

[8] L.
Pelusi
, A.
Passarella
, and M. Conti, “Opportunistic networking: data forwarding in disconnected mobile ad hoc networks”,
IEEE Communications
Magazine
,
Vol
: 44, Issue: 11, November 2006, pp. 134
-
141.

[9] T.
Spyropoulos
, K.
Psounis
, and C. S.
Raghavendra
. “Single
-
copy routing in intermittently connected mobile Networks”. ”,
in Proceedings of First
Annual IEEE Communications Society Conference on Sensor and Ad Hoc Communications and Networks (SECON 2004)
, Santa Clara, CA, USA,
4
-
7 Oct. 2004, pp. 235
-
244.

[10] S. Jain, K. Fall, and R.
Patra
, “Routing in a Delay Tolerant Network”,
in proceedings of ACM SIGCOMM 2004
, Portland/ Oregon/ USA, 30 Aug.
-
3
Sept. 2004, pp. 145

158.

[11] A.
Vahdat
, and D. Becker, “Epidemic routing for partially connected ad hoc networks”,
Technical Report CS
-
2000
-
06, Dept. of Computer Science,
Duke University
, Durham, NC, 2000.

[12] T.
Spyropoulos
, K.
Psounis
, and C. S.
Raghavendra
, “Spray and wait: An efficient routing scheme for intermittently connected mobile networks”,
in
proceedings of ACM SIGCOMM Workshop on Delay
-
Tolerant Networking (WDTN ’05)
, Philadelphia, PA, USA, 22
-
26 Aug. 2005, pp. 252

259.

[13] T.
Spyropoulos
, K
Psounis

and C.S.
Raghavendra
, “Spray and Focus: Efficient Mobility
-
Assisted Routing for Heterogeneous and Correlated
Mobility”,
in proceedings of the Fifth IEEE International Conference on Pervasive Computing and Communications Workshops (
PerComW

'07)
,
White Plains, NY, 19
-
23 March 2007, pp. 79
-
85.

[14] J.
Makhlouta
, H.
Harkous
, F.
Hutayt

and H.
Artail
. “Adaptive Fuzzy Spray and Wait: Efficient Routing for Opportunistic Networks”,
in
proceedings of IEEE International Conference on Selected Topics in Mobile and Wireless Networking(
iCOST
)
, Shanghai, China, 10
-
12 October,
2011, pp. 64


69.


[15] A. Lindgren, A.
Doria
, and O.
Schelen
, “Probabilistic routing in intermittently connected networks”,
ACM SIGMOBILE, Mobile Computing and
Communications Review
,
Vol
: 7, Issue: 3, July 2003, pp. 19

20.

References (contd.)

[16] Ting
-
Kai Huang,
Chia
-
Keng

Lee, Ling
-
Jyh

Chen. “
PRoPHET
+: An Adaptive
PRoPHET
-
Based Routing Protocol for Opportunistic Network”,
in proceedings of

24th IEEE International Conference on Advanced Information Networking and Applications (AINA 2010),

Perth, Australia, 20
-
13 April 2010, pp. 112
-
119.

[17] C.
Boldrini
, M. Conti, I.
Iacopini

and A.
Passarella
, “HiBOp: a History Based Routing Protocol for Opportunistic Networks”,
in proceedings of IEEE
International Symposium on World of Wireless, Mobile and Multimedia Networks, 2007 (
WoWMoM

2007)
, Espoo, Finland, 18
-
21 June 2007, pp. 1
-
12.

[18] Y. Liu, J.
Niu

and J. Ma, “Content Encounter Probability Based Message Forwarding in Opportunistic Networks”,
in proceedings of
Ist

IEEE International
Conference on Information Science and Engineering (ICISE '09)
, Nanjing, 26
-
28 Dec. 2009, pp 2589
-
2594.

[19] T.
Kathiravelu
, N.
Ranasinghe

and A. Pears, “A robust proactive routing protocol for intermittently connected opportunistic networks”,
in proceedings of
Seventh IEEE International Conference on Wireless And Optical Communications Networks (WOCN 2010)
, Colombo, Sri Lanka, 6
-
8 Sept. 2010, pp. 1
-
6.

[20] A.
Greede
, S. M. Allen and R. M. Whitaker, “RFP: Repository Based Forwarding Protocol for Opportunistic Networks”,
in proceedings of third
Third

International Conference on Next Generation Mobile Applications, Services and Technologies (NGMAST '09),


Cardiff, Wales, 15
-
18 Sept. 2009, pp
329
-
334.

[21] J. Burgess, B. Gallagher, D. Jensen, and B. N. Levine, “
Maxprop
: Routing for vehicle
-
based disruption
-
tolerant networks”,
in proceedings of 25th IEEE
International Conference on Computer Communications (INFOCOM 2006)
, Barcelona, Spain, 23
-
29 April 2006, pp. 1

11.

[22] M.
Musolesi,S
.
Hailes

and C.
Mascolo
, “Adaptive Routing for Intermittently Connected Mobile Ad Hoc Network”,
in proceedings of Sixth IEEE
International Symposium on World of Wireless Mobile and Multimedia Network (WOWMOM '05)
, Taormina
-
Giardini

Naxos, Italy, 13
-
16 June 2005, pp
183
-
189.

[23] B. Burns, O. Brock, and B. N. Levine, “MV Routing and Capacity Building in Disruption Tolerant Networks”,
in proceedings of IEEE 24th Annual Joint
Conference of the IEEE Computer

and

Communications Societies (INFOCOM 2005)
Vol
: 1
, Miami, FL, USA, 13
-
17 March 2005, pp. 398
-
408.

[24] J.
Widmer

and J.
-
Y. Le
Boudec
, “Network Coding for Efficient Communication in Extreme Networks,”
in Proceedings of ACM SIGCOMM workshop on
Delay
-
tolerant networking
, Philadelphia, PA, 22

26 Aug. 2005, pp. 284
-
291.

[25] C. E. Perkins and P.
Bhagwat
, “Highly dynamic Destination
-
Sequenced Distance
-
Vector routing (DSDV) for mobile computers
”, in proceedings of the ACM
Conference on Communications Architecture, Protocols and Applications (SIGCOMM ‘94)
, London, England UK, 31 August
-

02 September, 1994, pp. 234
-
244.

[26] R. E.
Kalman
. “A new approach to linear filtering and prediction problems”,
Transactions of the ASME


Journal of Basic Engineering
,
Vol
: 82, No. (Series
D), March 1960, pp. 35
-
45.

[27] T. Camp, J.
Boleng
, and V. Davies, “A survey of mobility models for ad hoc network research”,
Wireless Communications & Mobile Computing (WCMC):
Special issue on Mobile Ad Hoc Networking: Research, Trends and Applications
,
Vol
: 2, No. 5, 2002, pp. 483
-
502.

[28] “Delay Tolerant Network Research Group (DTNRG)”, http://www.dtnrg.org/.

[29] The CMU Monarch Project’s wireless and mobility extensions to ns
-
2.
http://www.monarch.cs.rice.edu/cmu
-
ns.html
.

[30] A.
Keranen
, “ Opportunistic Network Environment Simulator”,
Special Assignment Report, Helsinki University of Technology, Dept. of Communications
and Networking
, May 2008.

References (contd.)

[31]
Frans

Ekman
, Ari
Ker
¨
anen
,
Jouni

Karvo
, and
J
¨
org

Ott
, “Working day movement model”,
in proceeding of the 1st ACM

SIGMOBILE workshop on Mobility models (
MobiHoc

2008)
, Hong Kong SAR, China, 27
-

30 May, 2008, pp. 33

40.

[32] James Scott, Richard
Gass
, Jon
Crowcroft
, Pan
Hui
, Christophe
Diot
, and
Augustin

Chaintreau
, “CRAWDAD data set
cambridge
/haggle (v. 2006
-
09
-
15)”, Downloaded from
http://crawdad.cs.dartmouth.edu/cambridge/haggle
, May, 2009.


[33]
OMNeT
++, Downloaded from
http://www.omnetpp.org/

[34] R. Barr, Z. J. Haas, and R. van
Renesse
, “
Jist
: An efficient approach to simulation using virtual machines”,
Software Practice &
Experience
,
John Wiley & Sons, Inc.

New York, NY, USA,

Vol
: 35, Issue: 6, May 2005, pp 539
-
576.

[35]M.
Musolesi
, S.
Hailes
, and C.
Mascolo
, “An ad hoc mobility model founded on social network theory”,
in proceedings of 7
th

ACM
international symposium on Modeling, analysis and simulation of wireless and mobile systems (
MSWiM

'04)
, Venice, Italy, 4
-

6
October, 2004, pp. 20
-
24.


[36] The Network Simulator (NS
-
2).
www.isi.edu/nsnam/
ns
/

[37] T. Small and Z. J. Haas, “The Shared Wireless
Infostation

Model


A New Ad Hoc Networking Paradigm (or Where There is a
Whale, there is a Way),”
in proceedings Of 4th ACM

International
symposium

on

Mobile Ad Hoc Networking and Computing

(
MobiHoc

2003)
, Annapolis, MD,USA, 1

3 June, 2003, pp. 233
-
244.

[38] David J. Goodman, Joan
Borras
,
Narayan

B.
Mandayam

and Roy D. Yates, “INFOSTATIONS: A New System Model for Data and
Messaging Services,”
IEEE Vehicular Technology Conference 1997( VTC’97)
,
Vol
: 2, May 1997, pp. 969

973.

[39] S. Jain, R. C. Shah,
W.Bbrunette
, G.
Borriello

and S. Roy, “Exploiting Mobility for Energy Efficient Data Collection in Wireless
Sensor Networks,”
ACM/
Kluwer

Mobile Networks and Applications (MONET)
,
Vol
: 11, no. 3, June 2006, pp. 327

339.

[40] W. Zhao, M.
Ammar
, and E.
Zegura
, “A Message Ferrying Approach for Data Delivery in Sparse Mobile Ad Hoc Networks,”
in
proceedings of 5th ACM Int’l.
Symp
. Mobile Ad

Hoc Networking and Computing 2004 (
MobiHoc

‘04)
, ACM Press, Tokyo, Japan,
24
-
26 May 2004, pp. 187

198.

[41] Marco Conti and Mohan Kumar, “Opportunities in opportunistic computing”
IEEE Computer Journals & Magazines
,
Vol
: 43, Issue: 1,
JANUARY 2010, pp. 42
-
50.

[42] A.
Chaintreau
, P.
Hui
, J.
Crowcroft
, C.
Diot
, R.
Gass
, and J. Scott, “Impact of human mobility on the design of opportunistic
forwarding algorithms”
in proceedings of 25th IEEE International Conference

on Computer Communications (INFOCOM 2006)
,
Barcelona, Spain, 23
-
29 April, 2006, pp. 1
-
13.

[43] L.
Pelusi
, A.
Passarella
, and M. Conti, "Encoding for Efficient Data Distribution in Multi
-
hop Ad hoc Networks"
in Handbook of
Wireless Ad hoc and Sensor Networks A.
Boukerche
, Editor, Wiley and Sons Publisher, 2007
.

[44] J. Yang, Y. Chen, M.
Ammar
, and C. Lee, "Ferry replacement protocols in sparse MANET message ferrying systems",
in proceedings
of IEEE Wireless Communications and Networking Conference
, New Orleans, USA, 13
-
17 March 2005, pp. 2038
-

2044.

[45] S.
Merugu
, M.
Ammar
, and E.
Zegura
, “Routing in space and time in networks with predictable mobility”,
Technical Report GIT
-
CC
04
-
7
, Georgia Institute of Technology, 2004.

References (contd.)

[46] M. Conti, J.
Crowcroft
, S. Giordano, P.
Hui
, H. A. Nguyen and A.
Passarella
, “Routing
Issues in Opportunistic Networks”,

MiNEMA

State
-
of
-
the
-
Art Book
, H. Miranda, L.
Rodrigues
, B.
Garbinato

Editors, Springer, 2009.

[47] I.
Woungang
, M. K. Denko, "Credit
-
based Cooperation Enforcement Schemes Tailored
to Opportunistic Networks", Chapter 3 in: M. Denko (Eds.), Mobile Opportunistic
Networks: Architectures, Protocols and Applications,
Auerbach

Publications,
Taylor &
Francis Group, Boca Raton, Florida, ISBN: 978
-
142
-
008
-
812
-
0, ISBN 10: 142
-
008
-
812
-
2
, 292 pages, 2011.

[48]
LeBrun
, Chen
-
Nee
Chuah
, D.
Ghosal
, and M. Zhang, “Knowledge based opportunistic
forwarding in vehicular wireless ad hoc networks”,
in

proceedings of
61st IEEE
Vehicular Technology Conference (VTC 2005
-
Spring)
, 30 May
-
1 June 2005, pp. 2289

2293 Vol. 4.

[49] J.
Leguay
, T. Friedman, and V. Conan, “Evaluating mobility pattern space routing for
DTNs”,
in proceedings of 25th IEEE International Conference on Computer
Communications (INFOCOM 2006),
Barcelona, Spain, 23
-

29 April, 2006, pp. 1

10.

[50]
Chien
-
Shiu

Lin, Wei
-
Shyh

Chang, Ling
-
Jyh

Chen, and Cheng
-
Fu Chou, “Performance
study of routing schemes in delay tolerant networks”,
in proceedings of the 22nd
International Conference on

Advanced Information Networking and Applications


Workshops (AINAW ’08)
, Washington, DC, USA, 25
-
28 March 2008, pp. 1702

1707,


Thanks for your
attention!