Mobile Computing Unit2 P2

8/12/2019 Mobile Computing Unit2 P2

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Mobile communication systems: Cellular system

infrastructure, Registration, Handoff parameter and

underlying support Roaming support, Multicasting,Security and privacy, Firewall and system security.

Eiting wireless system: !M"S, #S$%&, 'SM, #M($

)***.

Unit-3

1

(1KMEF5-Mobile Computing)Mob. Comm. Systems


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1. Registration2. Handoff Parameters and Underlying Support

3. Roaming Support

4. Multicasting

5. Security and Privacy

. !ire"alls and System Security

2

(1KMEF5-Mobile Computing)Unit-III


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#ac$ %S &%ase Station' consists of(Major Components)

1' BTS&%ase (ransceiver System' and

2' BSC&%ase Station )ontroller'

3' AUC&*ut$entication )enter'

4' EIR&e+uipment ,dentity register'

5' HLR&Home -ocation register'' VLR&isitor -ocation Register'

'

Cellular System Infrastructure



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Blck !ia"ram f the Cellular System Infrastructure



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1) VLRcontains information a/out all visiting MSs int$at particular area of MS)

2) VLR$as pointers to t$e H-R0s of visiting MS

3) VLR$elps in /illing and access permission to t$e

visiting MS

4) AUCprovides aut$entication and encryption

parameters

5) EIRcontains identity of e+uipments t$at prevents

service to unaut$oried MSs




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6) VLR HLRprovides support to mo/ility ena/leuse of same Mo/. over a "ide range

7) HLRis located at MSC"$ere MS is initially

registered for /illing *ccess ,nformation

8) VLRcontains information of all MSs visiting t$at

perticular MS) and points to t$e H-R of t$e visiting

MSs for ec$anging related information MS


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#ac$ MS &Mo/ile Station' must /e registered at oneof t$e MS)s &Mo/. Station )ontroller'

($is is done /y ec$anging beacon sina!s.

#e"istratin



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Beaconin"

%ase Station periodically /roadcasts 6%eacon signals7

to determine and test near/y MSs &Mo/ile Stations'

Eac+ MS listens for eacon Signals and if it +ears from

new S, it adds it to t+e active -Beacn $ernel %a&le

9

Beacn Si"nal


* p$one

outside t$esu/scription

area


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'pplicatins f Beacn Si"nals


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1' 8ireless system needs to 9no" "$et$er MS is currently

located in its $ome area or some ot$er area &routing of

incoming calls'

2' ($is is done /y periodically ec$anging signals /et"een %S

and MS 9no"n as %eacons

3' %S #e$io%ica!!&/roadcasts /eacon signal &1 signal persecond' to determine and test t$e MSs around

4' #ac$ MS listens to t$e /eacon: if it $as not $eard it previously

t$en it adds it to t$e ac'i(e beacon e$ne! 'ab!e

5'

($is information is used /y t$e MS to locate t$e nearest %S' ,nformation carried /y /eacon signal; cellular net"or9

identifier: timestamp: gate"ay address ,< of t$e paging area:

etc.

11

egistration(1KMEF5-Mobile Computing)Unit-III


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HANDOFF,s a Change of radio resourcesfrom one cell to an ad>acent one.

* free c$annel must /e availa/le in a ne" cell "$enever $andoff

occurs for *n%is$*#'e%service.

Handoff depends on cell si/e, boundary lengt+, signal strengt+, fading,reflection, etc.

Handoff can be initiated by MS or BS and

could be due to

1. Radio lin!. Net"or #anage#ent

$. Ser%ice issues


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Radio lin0$type +andoff is due to mobility of t+e MS and

depends on t+e relative values of t+e radio lin0 parameters

,t depends on;

1. ?um/er of MSs in t$e cell

2. ?um/er of MSs t$at $ave left t$e cell3. ?um/er of calls generated in t$e cell

4. ?um/er of calls transferred from t$e neig$/oring cells

5. ?um/er and duration of calls terminated in t$e cell

.

?um/er of calls t$at "ere $andoff to neig$/oring cells@. )ell d"ell time

HANDOFF &ara#eters


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?et"or9 management may cause $andoff A if t$ere is

drastic im/alance of traffic in ad>acent cells and optimal

/alance of resources is re+uired

HANDOFF &ara#eters

Service related +andoff is due to t+e degradation of 1oS23uality of service4 and Handoff could be invo0ed w+en suc+

situation is detected.

Factors t+at define Handoff: 5


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HANDOFF &ara#etersFactors t+at decide the timeof t+e Handoff: 5

&. Signal strengt+

). Signal p+ase

6. Combination of above two

%. it error rate 2ER47. 8istance

?eed for Handoff is determined /y;

1' Signal strengt$

2' ),R &carrier to interference ratio'


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'ypes of Handoff1. Hard $andoff &Break before make'

2. Soft Handoff &Make before break'


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So,' +an%o,,&Make before break'1. ,n )


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oa#ing Support

&4 (o move from a cell controlled by one MSC area to a cell

connected to anot+er MSC

)4 eacon signals and t+e use of H9R$9R allow t+e MS to roam

anyw+ere provided t+e same service provider using t+at particular

fre3uency band, is t+ere in t+at region


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oa#ing Support?um/er of cells are controlled /y a MS): and depending on t$e

destination: t$e signals go t$roug$ t$e infrastructure /et"een t$e MSs

and eisting $ome or commercial telecommunication systems.

MS)s are connected to t$e /ac9/one net"or9 via different gate"ays.

&Ref !igure'

the #eal pr&lem:is routing of t+e pac0ets to appropriate end

points of t+e bac0bone networ0.


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oa#ing Support


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oa#ing Support

&4 !ssume MSC& to be t+e +ome of t+e MS for registration, billing, aut+entication,

etc.

)4 ;+en +andoff is from position -a to -b, t+e routing can be done by MSC& itself

64 ;+en +andoff is from position -b to -c , t+en bi$directional pointers are set up

to lin0 t+e H9R of MSC& to 9R of MSC)

%4 ;+en +andoff occurs at -d or -e, routing of information using H9R$9R may

not be ade3uate 2-d is in a different paging area4

74 Concept of ac0bone networ0


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Information Transmission Path when MS Hands Off from b to c


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Illustration of MSC Connections to Bacbone !etwor "

#outin$%#eroutin$

i


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Bacbone Net"or1' Routing done according to t$e topology and connectivity

of t$e /ac9/one net"or9

2' ($e dotted lines s$o" t$e possi/le pat$s for a call

$eaded for different MS locations

3' Bne option is to find a router along t$e original pat$:

from "$ere a ne" pat$ needs to start to reac$ t$e MS)

along t$e s$ortest pat$

U i III


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Home &$ents 'H&() *orei$n &$ents '*&( and Mobile IP

&4 (wo important software modules are associated wit+

routers, hme a"ent2H!4 and frei"n a"ent2F!4

)4 MS is registered wit+ a router, mostly a router closest to t+e

+ome MSC can be used to maintain its H!

64 ! router ot+er t+an closest one could also serve as an H!

%4


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Home MSC and Home &$ent 'H&( for the Pre+ious !etwor

U it III


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Call ,stablishment usin$ H&-*&

($ere are 13 s'e#sto esta/lis$ a call

using H*A!*

U it III


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&4 ;+enever a MS moves to a new networ0, it still retains its

initial H!)4 (+e MS detects t+e F! of t+e new networ0, by sensing t+e

periodic beacon signals w+ic+ F! transmits

64 MS can also itself send a"ent slicitatin messa"esto

w+ic+ F! responds%4 ;+en F! detects a new MS, it allocates a C'2care of

address4 to t+e MS, using dynamic +ost configuration

protocol 28HC"4

74


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>4 H! confirms its binding t+roug+ a reply to t+e MS

?4 ! message sent from an arbitrary source to t+e MS at t+e+ome address is received by t+e H!

@4 inding is c+ec0ed, t+e Co! of t+e MS is encapsulated in

t+e pac0et and forwarded to t+e networ0

&*4 #f Co! of t+e F! is used, t+en pac0et reac+es F!, itdecapsulates pac0et and passes to MS at t+e lin0 layer

&&4 #n an internet environment, it is called (&ile I)

&)4 !fter binding time, if MS still wants to +ave pac0ets

forwarded t+roug+ H!, it needs to renew its registration

&64 ;+en MS returns to its +ome networ0, it intimates its H!

Call ,stablishment usin$ H&-*& 'Conti..(

U it III


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Registration "rocess

etween F!, MS,

and H! ;+en t+e

MS Moves to a

"aging area

clic9 45

end

Unit III


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ecap*ssignment of ,P *ddressC

I !ddress is designed to "ork "ith #tationar$ %osts&

%ecause part of t$e ,P address defines net"or9 to "$ic$ t$e Host

is attac$ed

Real ,ssue of ,P *ddress D.

1' Stationary Host

2' Mo/ile Host

;+enHo

stmovesfrom

onenetw

or0to

anot+er,(

+e#"!dd

ressstructuren

eedsto

bemodifie

dA

)refi* r +/,-i Suffi* r st-i part


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ecap

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, , , , , , , , ,192,1,25',1 192,1,25',2 192,1,25',25'

192,1,25',11 e

/&! 01

n/w n$mber 123.145.367.

n/w mas% 255,255,255,0

&roadcast 123.145.367.366

- o. machines 25'

, , , , , , , , ,

10,0,0,5 e

10,0,0,1 10,0,0,2 10,0,0,15

'+ 0nBw number 10.0.0.11

nBw mas0 )77.)77.)77.)6%

roadcast &*.*.*.6)

of mac+ines )*

10,25',25',5 e1

10,25',25', e1'+ 03n/2 num&er 10.4.4.4

n/2 mask ...

Bracast 10.4.4.

f machines


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ecap

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;+enHostm

ovesfrom

onenetw

or0to

anot+er,(+e#"!dd

ressstruc

tureneed

sto

bemodifiedA

!our Solutions;

1.

-et t$e MH c$ange its address: as it goes to ne" net"or9&


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ecapMobile Internet roto!ol (Mobile I)"

Here Mobile Host has two IP addresses,One is called #ome $%%ress&

Another is called C&re ' $%%ress(COA)

HereMobile Address is always perm&nent, AndC'$changes as Mobile host moves from one networ toanother networ!

(o ma9e t$e 6c$ange of address7 transparent to rest of t$e internet: "e

re+uire *gents.

)alled as Ho-e Aen'&H*'

and .o$ein Aen'&!*'

(1KMEF5 M bil C i ) Unit III


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10.1.3.

(&ile st

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ecap#$(Home Agent), F$("oreign Agent) & Mobile IConce#t$

10.1.3.1

10.1.3.

Internet

me +et2rk

+/2-I!: 10.1.3.0

14.13.15.6

+/2-I!: 14.0.0.0

me 'ress: 10.1.3.

C7' 8Care 7f 'ress9: 14.13.15.6

osition of

Ho-e Aen'.o$ein Aen'

rei"n +et2rk


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(1KMEF5 M bil C ti ) Unit-III


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ecapMore #ophistication can be done ''&

MH itself can act as .Ain other "ordsMH an% .A can be sa-e/

2 ma>or t$ings are re+uired for t$at D.

1.

MH must /e a/le to receive )B* &)are of *ddress' /y itself:"$ic$ is done t$roug$


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ecapC-lcate Care f 'ress:

8$en MH acts as !*: ($e )B* is called as )A)B*

*dvantage


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ecap)ommunication of Remote Host&RH' Mo/ile Host&MH';

(o communicate "it$ RH: MH goes t$roug$ 3 p$ases

1' *gent discovery

2' Registration

3'


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ecap


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ecap?o" /ac9 to DDDD. s!i%e03

Mo/ile ?et"or9 -ayer

Mo/ile (ransport -ayer

/earn

abou

t this


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(1KMEF5-Mobile Computing) Unit-III


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(1KMEF5-Mobile Computing)Unit III

Messa$e *orwardin$ usin$ H&-*& Pair



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(1KMEF5-Mobile Computing)Unit III

#outin$ in Bacbone #outers

Ho .A ,in%s HA o, '+e MS1. Bne approac$ is to $ave a glo/al ta/le at eac$ router of eac$ MS) so

t$at t$e route from !* to H* for t$at MS can /e determined

2.


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(1KMEF5 Mobile Computing)Unit III

Illustr&tion o &ging $re&s ($s) &n% *&!+bone ,outerInter!onne!t



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Illustr&tion o &ging $re&s ($s) &n% *&!+bone ,outerInter!onne!t


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&t is tunneling/

($e process of creating indirect lin9s and $aving virtual /idirectional

pat$s /et"een H* and !* is 9no"n as tunneling and is very useful in

supporting indirection in suc$ a mo/ile environment.

$)


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Ho-e2o

$)

5$ob!e

-

8e $ave follo"ing information

mo/ile $ost $ome address ; 13G.45..@=1

mo/ile $ost careAofAaddress ; 14.5..I=

remote $ost address ; [email protected]=24

$ome agent address ; 13G.45.1G.2G=1foreign agent address ; [email protected].=

S$o" contents of t$e ,P datagram $eader sent from t$e remote

$ost to t$e $ome agent.

refer I)-in-I) encapsulatin

Documents

Mobile Computing Unit2 P2