Course on Wireless 05

7/25/2019 Course on Wireless 05

1/298

Wireless Networking TechnologiesWLAN, WiFi Mesh and WiMAX


2/298


3/298

Wireless Networks


4/298

Sridhar Iyer IIT Bombay 4

Wireless networks

Access co/uting3counication ser&ices, on the o&e

Wireless WANs Cellular Networks4 5'M, 56#', CDMA

'atellite Networks4 7ridiu

Wireless LANs WiFi Networks4 *+-..

6ersonal Area Networks4 $luetooth

Wireless MANs WiMaX Networks4 *+-.2

Mesh Networks4 Multi8ho/ WiFi

Adhoc Networks4 useful when infrastructure not a&aila!le


5/298


Liitations of the o!ile en&ironent

Liitations of the WirelessNetwork liited counication !andwidth fre%uent disconnections

heterogeneit" of fragented networks

Liitations 7/osed !" Mo!ilit" route !reakages

lack of o!ilit" awareness !" s"ste3a//lications

Liitations of the Mo!ile De&ice short !atter" lifetie

liited ca/acities


6/298

Mo!ile counication

Wireless &s- o!ile 9:a/les

stationar" co/uter la/to/ in a hotel (/orta!le) wireless LAN in historic !uildings 6ersonal Digital Assistant (6DA)

7ntegration of wireless into e:isting fi:ed networks4 Local area networks4 7999 *+-.., 9T'7 (;769#LAN)

Wide area networks4 Cellular


7/298


Wireless &3s Wired networks

#egulations of fre%uencies Liited a&aila!ilit", coordination is re%uired

useful fre%uencies are alost all occu/ied

$andwidth and dela"s Low transission rates

= few >!its3s to soe M!it3s-

;igher dela"s

= se&eral hundred illiseconds

;igher loss rates

= susce/ti!le to interference, e-g-, engines, lightning Alwa"s shared ediu

Lower securit", si/ler acti&e attacking

radio interface accessi!le for e&er"one

secure access echaniss i/ortant


8/298


!/s

@2 >!/s

@? M!/s

M!/s

@8.. M!/s

.8 M!/s *+-..

Wireless Technolog" Landsca/e

$luetooth

*+-..!

*+-..Ba,!

Tur!o -..a

7ndoor

.+

Long rangeoutdoor

@> +>

Long distanceco-

+ @+>

wave p-to-p links

-.. /8to8/ link

5


9/298


#eference odel

A//lication

Trans/ort

Network

Data Link

6h"sical

Mediu

Data Link

6h"sical

A//lication

Trans/ort

Network

Data Link

6h"sical

Data Link

6h"sical

Network Network

#adio


10/298


9ffect of o!ilit" on /rotocol stack

A//lication new a//lications and ada/tations

ser&ice location, ultiedia

Trans/ort congestion and flow control

%ualit" of ser&ice

Network addressing and routing

de&ice location, hand8o&er

Link edia access and securit"

6h"sical transission errors and interference


11/298


6ers/ecti&es

Network designers4 Concerned with cost8effecti&edesign Need to ensure that network resources are efficientl" utiliEed

and fairl" allocated to different users-

Network users4 Concerned with a//lication ser&ices Need guarantees that each essage sent will !e deli&ered

without error within a certain aount of tie-

Network /ro&iders4 Concerned with s"steadinistration Need echaniss for securit", anageent, fault8tolerance

and accounting-


12/298

#F $asics


13/298


Factors affecting wireless s"ste design

Fre%uenc" allocations What range to o/erate Ma" need licenses-

Multi/le access echanis ;ow do users share the ediu without interfering

Antennas and /ro/agation What distances 6ossi!le channel errors introduced-

'ignals encoding

;ow to i/ro&e the data rate 9rror correction

;ow to ensure that !andwidth is not wasted


14/298


Fre%uencies for counication

0LF G 0er" Low Fre%uenc" H;F G Hltra ;igh Fre%uenc" LF G Low Fre%uenc" ';F G 'u/er ;igh Fre%uenc" MF G Mediu Fre%uenc" 9;F G 9:tra ;igh Fre%uenc" ;F G ;igh Fre%uenc" H0 G Hltra&iolet Light

0;F G 0er" ;igh Fre%uenc"

Fre%uenc" and wa&e length4 G c3f wa&e length , s/eed of light c


15/298


Wireless fre%uenc" allocation

#adio fre%uencies range fro >;E to ?++5;I (7TH)

Microwa&e fre%uenc" range . 5;E to ?+ 5;E

Directional !eas /ossi!le

'uita!le for /oint8to8/oint transission Hsed for satellite counications

#adio fre%uenc" range


16/298


Fre%uencies for o!ile counication

0;F83H;F8ranges for o!ile radio si/le, sall antenna for cars

deterinistic /ro/agation characteristics, relia!le connections

';F and higher for directed radio links, satellitecounication

sall antenna, focusing

large !andwidth a&aila!le

Wireless LANs use fre%uencies in H;F to ';F s/ectru soe s"stes /lanned u/ to 9;F

liitations due to a!sor/tion !" water and o:"gen olecules(resonance fre%uencies)

= weather de/endent fading, signal loss caused !" hea&"rainfall etc-


17/298


Fre%uenc" regulations

Fre%uencies fro >;E to


18/298


Wireless transission

Wireless counication s"stes consist of4 Transitters

Antennas4 radiates electroagnetic energ" into air

#ecei&ers 7n soe cases, transitters and recei&ers are

on sae de&ice, called transcei&ers-

Transmitter Receiver

ntennantenna


19/298


Transitters

m!"i#ier

$sci""ator

%i&er 'i"ter m!"i#ier

ntenna

Transmitter

S(!!ose yo( )ant to *enerate a si*na" that is sent at 900 %+, andthe ori*ina" so(rce *enerates a si*na" at 300 %+,-

.m!"i#ier / stren*thens the initia" si*na"

.$sci""ator / creates a carrier )ave o# 600 %+,

.%i&er / combines si*na" )ith osci""ator and !rod(ces 900 %+,a"so does mod("ation etc.'i"ter / se"ects correct #re(ency.m!"i#ier / Stren*thens the si*na" be#ore sendin* it

So(rce


20/298

Antennas


21/298


Antennas

An antenna is an electrical conductor or s"ste of

conductors to send3recei&e #F signals Transission 8 radiates electroagnetic energ" into s/ace

#ece/tion 8 collects electroagnetic energ" fro s/ace

7n two8wa" counication, the sae antenna can !e

used for transission and rece/tion

$mnidirectiona" ntenna

"o)er #re(ency

irectiona" ntenna

hi*her #re(ency


22/298


#adiation and rece/tion of electroagnetic wa&es,

cou/ling of wires to s/ace for radio transission 7sotro/ic radiator4 e%ual radiation in all directions

(three diensional) 8 onl" a theoretical referenceantenna

#eal antennas alwa"s ha&e directi&e effects(&erticall" and3or horiEontall")

#adiation /attern4 easureent of radiation aroundan antenna

Antennas4 isotro/ic radiator

E"

:

E

" : idealisotro/icradiator


23/298


24/298


Antennas4 directed and sectoriEed

side &iew (:"8/lane)

:

"

side &iew ("E8/lane)

E

"

to/ &iew (:E8/lane)

:

E

to/ &iew, < sector

:

E

to/ &iew, 2 sector

:

E

Often used for icrowa&e connections or !ase stations

for o!ile /hones (e-g-, radio co&erage of a &alle")

directedantenna

sectoriEedantenna


25/298


Antenna odels

In OmniMode:

Nodes recei&e signals with gain Go

In DirectionalMode:

Ca/a!le of !eaforing in s/ecified direction Directional 5ain Gd (Gd > Go)


26/298


Directional counication

#ecei&ed 6ower (Transit /ower)

J(T: 5ain) J (#: 5ain)

Directional gain is higher

Directional antennas useful for47ncrease Krange, kee/ing transit /ower constant#educe transit /ower, kee/ing range co/ara!lewith oni ode


27/298


Co/arison of oni and directional

7ssues Oni Directional

'/atial #euse Low ;igh

Connecti&it" Low ;igh

7nterference Oni Directional

Cost Co/le:it" Low ;igh


28/298


Antennas4 di&ersit"

5rou/ing of or ore antennas

ulti8eleent antenna arra"s

Antenna di&ersit" switched di&ersit", selection di&ersit"

= recei&er chooses antenna with largest out/ut

di&ersit" co!ining= co!ine out/ut /ower to /roduce gain

= co/hasing needed to a&oid cancellation

3?33?

ground /lane

33

3


29/298

'ignal 6ro/agation and Modulation


30/298


'ignals

/h"sical re/resentation of data

function of tie and location signal /araeters4 /araeters re/resenting the &alue of

data classification

continuous tie3discrete tie continuous &alues3discrete &alues

analog signal G continuous tie and continuous &alues

digital signal G discrete tie and discrete &alues

signal /araeters of /eriodic signals4

/eriod T, fre%uenc" fG.3T, a/litude A, /hase shift sine wa&e as s/ecial /eriodic signal for a carrier4

s(t) G Atsin( ft t t)


31/298


32/298


Attenuation4 6ro/agation #ange


33/298


Attenuation

'trength of signal falls off with distance o&ertransission ediu

Attenuation factors for unguided edia4

#ecei&ed signal ust ha&e sufficient strength so thatcircuitr" in the recei&er can inter/ret the signal

'ignal ust aintain a le&el sufficientl" higher thannoise to !e recei&ed without error

Attenuation is greater at higher fre%uencies, causingdistortion

A//roach4 a/lifiers that strengthen higherfre%uencies


34/298


35/298


'ignal can take an" different /aths !etween sender and recei&er due toreflection, scattering, diffraction

Tie dis/ersion4 signal is dis/ersed o&er tie interference with Kneigh!or s"!ols, 7nter '"!ol 7nterference (7'7)

The signal reaches a recei&er directl" and /hase shifted distorted signal de/ending on the /hases of the different /arts

Multi/ath /ro/agation

signal at sender

signal at recei&er

LO' /ulsesulti/ath/ulses


36/298


9ffects of o!ilit"

Channel characteristics change o&er tie and location signal /aths change

different dela" &ariations of different signal /arts

different /hases of signal /arts

%uick changes in the /ower recei&ed

(short ter fading)

Additional changes in

distance to sender o!stacles further awa"

slow changes in the a&erage /owerrecei&ed (long ter fading)

short ter fading

long terfading

t

/ower


37/298


6ro/agation odes

arth

arth

arth

a ro(nd ave ro!a*ation

b Sy ave ro!a*ation

c :ine/o#/Si*ht ro!a*ation

Transmission

ntenna

Receivin*

ntenna

Si*na"

Si*na"

Ionos!here

Si*na"


38/298


39/298


Modulation and deodulation

s"nchroniEationdecision

digitaldataanalog

deodulation

radiocarrier

analog!ase!andsignal

.+..+.++. radio receiver

digitalodulation

digitaldata analog

odulation

radiocarrier

analog

!ase!andsignal

.+..+.++. radio transmitter


40/298


Digital odulation Modulation of digital signals known as 'hift >e"ing A/litude 'hift >e"ing (A'>)4

&er" si/le

low !andwidth re%uireents

&er" susce/ti!le to interference

Fre%uenc" 'hift >e"ing (F'>)4 needs larger !andwidth

6hase 'hift >e"ing (6'>)4 ore co/le:

ro!ust against interference

Man" ad&anced &ariants

. + .

t

. + .

t

. + .

t


41/298

Multi/le:ing Mechaniss


42/298


Multi/le:ing in ? diensions s/ace (si)

tie (t)

fre%uenc" (f)

code (c)

5oal4 ulti/le use

of a shared ediu

7/ortant4 guard s/aces neededP

s

s

(acknowledgeent) aftertransitting each frae kee/sco/" of last frae-

#ecei&er sends AC> if recei&ed

frae is error free- 'ender retransits frae if

AC>not recei&ed !efore tiere:/ires-

'i/le to i/leent !ut a"waste !andwidth-

9fficient 0ersion4 'liding Window


70/298

$andwidth and Dela"

$andwidth


71/298


$andwidth

Aount of data that can !e transitted /er unit tie e:/ressed in c"cles /er second, or ;ertE (;E) for analog

de&ices

e:/ressed in !its /er second (!/s) for digital de&ices

>$ G U.+ !"tes M!/s G .+U2 !/s

Link &3s 9nd8to89nd

$andwidth &3s !it width


72/298


$andwidth &3s !it width

Latenc" (dela")


73/298


Latenc" (dela")

Tie it takes to send essage fro /oint A to /oint $

Latenc" G 6ro/agation Transit 1ueue

6ro/agation G Distance 3'/eedOfLight

Transit G 'iEe 3 $andwidth

1ueueing not rele&ant for direct links

$andwidth not rele&ant if 'iEe G . !it

'oftware o&erhead can doinate when Distance is sall

#TT4 round8tri/ tie


74/298

Dela" X $andwidth /roduct


75/298


Dela" X $andwidth /roduct

.++s #TT and ?@M!/s $andwidth G @2+ >$ of data


76/298

TC6376 $asics


77/298

'witched networks


78/298


'witched networks


79/298


TC6376 la"ers

6h"sical La"er4 Transitting !its o&er a channel-

Deals with electrical and /rocedural interface to the

transission ediu-

Data Link La"er4 Transfor the raw /h"sical la"er into a Vlink for the

higher la"er- Deals with fraing, error detection, correction and

ulti/le access-


80/298


TC6376 la"ers (contd-)

Network La"er4Addressing and routing of /ackets-

Deals with su!netting, route deterination-

Trans/ort La"er4 end8to8end connection characteristics-

Deals with retransissions, se%uencing and

congestion control-

TC6376 la"ers (contd )


81/298


TC6376 la"ers (contd-)

A//lication La"er4 VVa//lication /rotocols-

Deals with /ro&iding ser&ices to users and a//licationde&elo/ers-

6rotocols are the !uilding !locks of a network

architecture-

Lower la"er ser&ices


82/298


Lower la"er ser&ices

Hnacknowledged connectionless ser&ice

No acknowledgeents, no connection 9rror reco&er" u/ to higher la"ers

For low error8rate links or &oice traffic

Acknowledged connectionless ser&ice Acknowledgeents i/ro&e relia!ilit" For unrelia!le channels- e-g-4 wireless s"stes

Acknowledged connection8oriented ser&ice 9%ui&alent of relia!le !it8strea in8order deli&er"

Connection esta!lishent and release

7nter8router traffic


83/298

T"/ical TC6 !eha&iour


84/298


!

"

#

$

%

%!

%"

% ! & " ' # ( $

Time (round trips)

CongestionW

indowsize

(segments)

Slow start

Congestion

avoidance

Slow start

threshold

T"/ical TC6 !eha&iour

'low start /hase


85/298


'low start /hase

=initialiEe4=Cwnd G .

=for (each AC>)

=Cwnd=until

=loss detection O#

=Cwnd R ssthresh

;ost A

onese)ment

#TT

;ost $

time

twose)ments

*o+rse)ments

Congestion a&oidance /hase


86/298


Congestion a&oidance /hase

3J Cwnd R threshold J3=Hntil (loss detection) B e&er" w AC>s4 Cwnd

=ssthresh G Cwnd3=Cwnd G .=/erfor slow start

1

;ost A ;ost $

time

#TT

*o+rse)ments

*ivese)ments

TC64 Fast retransit and Fast reco&er"


87/298


!

"

#

$

%

Time (round trips)

Windowsize(segments)

advertised window

,*ter *ast recover

TC64 Fast retransit and Fast reco&er"


88/298

*+-.. (WiFi) O&er&iew

Wireless LANs


89/298


Wireless LANs

7nfrared (7rDA) or radio links (Wa&elan) Ad&antages

&er" fle:i!le within the rece/tion area

Ad8hoc networks /ossi!le

(alost) no wiring difficulties

Disad&antages low !andwidth co/ared to wired networks

an" /ro/rietar" solutions

7nfrastructure &3s ad8hoc networks (*+-..)


90/298

Difference !etween wired and wireless


91/298


7f !oth A and C sense the channel to !e idle at the sae

tie, the" send at the sae tie- Collision can !e detected at senderin 9thernet- ;alf8du/le: radios in wireless cannot detect collision at

sender-

, . /

,

.

/

0t1ernet 2,3 4ireless 2,3

Carrier 'ense Multi/le Access (C'MA)


92/298


Carrier 'ense Multi/le Access (C'MA)

Listen !efore "ou s/eak Check whether the ediu is acti&e !efore sending a

/acket (i-e carrier sensing)

7f ediu idle, then transit

7f collision ha//ens, then detect and resol&e

7f ediu is found !us", transission follows4 .8 /ersistent

68 /ersistent

Non8/ersistent


93/298

$inar" 9:/onential $ackoff


94/298


$inar" 9:/onential $ackoff

.-On detecting .stcollision for /acket : station A chooses a nu!er r !etween + and .-

wait for r J slot tie and transit-

'lot tie is taken as J /ro/agation dela"

k- On detecting kthcollision for /acket :

choose r !etween +,.,--,(k.)

When &alue of k !ecoes high (.+), gi&e u/-

#andoiEation increase with larger window, !ut dela"increases-

;idden Terinal 6ro!le


95/298


A and C cannot hear each other-

A sends to $, C cannot recei&e A-

C wants to send to $, C senses a Kfree ediu(C' fails)

Collision occurs at $-

A cannot recei&e the collision (CD fails)-

A is Khidden for C-

., /

Effectofinterferencerange


96/298

Effect of interference range

Transmission #rom 1 2 )i"" #ai"

'olution for ;idden Terinals


97/298


'olution for ;idden Terinals

A first sends a Request-to-Send R!S" to $

On recei&ing #T', $ res/onds #lear-to-Send #!S"

;idden node C o&erhears CT' and kee/s %uiet Transfer duration is included in !oth #T' and CT'

9:/osed node o&erhears a #T'!ut not the CT' Ds transission cannot interfere at $

, . /R56

/56 /56

D,5,

DR56

Co/onents of 7999 *+ ..


98/298


Co/onents of 7999 *+-..architecture

The !asic ser&ice set ($'') is the !asic !uilding!lock of an 7999 *+-.. LAN

The o&als can !e thought of as the co&erage areawithin which e!er stations can directl"

counicate The 7nde/endent $'' (7$'') is the si/lest LAN- 7t

a" consist of as few as two stations

ad-1oc network BSS2BSS1

*+-.. 8 ad8hoc network (DCF)


99/298


( )

Direct counicationwithin a liited range 'tation ('TA)4

terinal with accessechaniss to thewireless ediu

$asic 'er&ice 'et ($'')4grou/ of stations using the

sae radio fre%uenc"

$%&'(( )*+

$''

$%&'(( )*+

$''.

'TA.

'TA?

'TA@

'TA

'TA other stations store ediu reser&ations distri!uted &ia #T' and CT'

t

'7F'

D7F'

data

AC>

defer access

otherstations

recei&er

sender data

D7F'

contention

#T'

CT''7F' '7F'

NA0 (#T')NA0 (CT')

*+-.. 8 6CF 7


106/298


67F'

stationsZNA0

wirelessstations

/oint

coordinator

D.

H.'7F'

NA0

'7F'D

H'7F'

'7F'

'u/erFraet+

ediu !us"

t.

*+-.. 8 6CF 77


107/298


tstationsZNA0

wirelessstations

/ointcoordinator

D for M!/s (Differential 1uadrature 6'>)

/rea!le and header of a frae is alwa"s transitted with . M!/s,rest of transission . or M!/s

chi//ing se%uence4 ., 8., ., ., 8., ., ., ., 8., 8., 8. ($arkercode)

a:- radiated /ower . W (H'A), .++ W (9H), in- .W 7nfrared

*@+8@+ n, diffuse light, t"/- .+ range

carrier detection, energ" detection, s"nchroniEation

'/read8s/ectru counications


137/298


'ource4 7ntersil

D''' $arker Code odulation


138/298


'ource4 7ntersil


139/298

*+-.. 8 MAC la"er


140/298


Traffic ser&ices

As"nchronous Data 'er&ice (andator") DCF Tie8$ounded 'er&ice (o/tional) 8 6CF

Access ethods

DCF C'MA3CA (andator")= collision a&oidance &ia randoiEed !ack8off echanis

= AC> /acket for acknowledgeents (not for !roadcasts)

DCF w3 #T'3CT' (o/tional)

= a&oids hidden3e:/osed terinal /ro!le, /ro&ides

relia!ilit" 6CF (o/tional)

= access /oint /olls terinals according to a list

contention window( d i d ! k ff

*+-.. 8 C'MA3CA


141/298


t

ediu !us"

D7F'D7F'

ne:t frae

(randoiEed !ack8offechanis)

station which has data to send starts sensing the ediu (Carrier'ense !ased on CCA, Clear Channel Assessent)

if the ediu is free for the duration of an 7nter8Frae '/ace(7F'), the station can start sending (7F' de/ends on ser&ice t"/e)

if the ediu is !us", the station has to wait for a free 7F' /lus an

additional rando !ack8off tie (ulti/le of slot8tie) if another station occu/ies the ediu during the !ack8off tie ofthe station, the !ack8off tier sto/s (fairness)

slot tie

direct access ifediu is free D7F'

*+-.. DCF !asic access


142/298


7f ediu is free for D7F' tie, station sends data

recei&ers acknowledge at once (after waiting for '7F') if the /acketwas recei&ed correctl" (C#C) autoatic retransission of data /ackets in case of transission

errors

t

'7F'

D7F'

data

AC>

waiting tie

otherstations

recei&er

senderdata

D7F'

contention

*+-.. #T'3CT'


143/298


7f ediu is free for D7F', station can send #T' with reser&ation/araeter (reser&ation deterines aount of tie the data /acket needs

the ediu) acknowledgeent &ia CT' after '7F' !" recei&er (if read" to recei&e) sender can now send data at once, acknowledgeent &ia AC> other stations store ediu reser&ations distri!uted &ia #T' and CT'

t

'7F'

D7F'

data

AC>

defer access

otherstations

recei&er

sender data

D7F'

contention

#T'

CT''7F' '7F'

NA0 (#T')NA0 (CT')

*+-.. 8 Carrier 'ensing


144/298


In I000 $!;%% carrier sensin is per*ormed

at the air interface (physical carrier sensing), and at the MAC la"er (.irtual carrier sensing)

91sical carrier sensin

detects /resence of other users !" anal"Eing all detected/ackets

Detects acti&it" in the channel &ia relati&e signal strengthfro other sources

Birt+al carrier sensinis done !" sending M6DH durationinforation in the header of #T'3CT' and data fraes

Channel is !us" if eit1erechaniss indicate it to !e

Duration field indicates the aount of tie (in icroseconds)re%uired to co/lete frae transission

'tations in the $'' use the inforation in the duration field toadSust their network allocation &ector (NA0)

*+-.. 8 Collision A&oidance


145/298


7f ediu is not free during D7F' tie--

5o intoCollision A&oidance4Once channel !ecoesidle, wait for D7F' tie /lus a randol" chosen!ackoff tie !efore atte/ting to transit

For DCF the !ackoff is chosen as follows4

When first transitting a /acket, choose a !ackoff inter&al inthe range [+,cw\ cwis contention window, noinall"


146/298


data

wait

$. G @

$ G .@

$. G @

$ G +

data

wait

.% and .! are


147/298


t

!us"

!oe

station.

station

station ., , @-@ or .. M!it3s

short s"nch- 'FD signal ser&ice ;9C /a"load

6LC6 /rea!le

(. M!it3s, D$6'>)

6LC6 header

( M!it3s, D16'>)

@2 .2 * * .2 &aria!le !its

length

.2

2 s , @-@ or .. M!it3s

'hort 6LC6 66DH forat (o/tional)

Channel selection (non8o&erla//ing)9uro/e (9T'7)


177/298


?++

[M;E\

?. ?*


178/298


Hser through/ut (.@++ !"te /ackets)4 @-< (2),.* (?), ? (


179/298


rate ser&ice /a"load

&aria!le !its

2 M!it3s

6LC6 /rea!le signal data

s"!ols. . &aria!le

reser&ed length tail/arit" tail /ad

2.22...? &aria!le

2, , ., .*, ?,


180/298


( )

?* data ? /ilot


181/298


@.@+ [M;E\@.*+ @


182/298


9nhance the current *+-.. MAC to e:/and su//ortfor a//lications with 1ualit" of 'er&ice re%uireents,and in the ca/a!ilities and efficienc" of the /rotocol-

9DCF Contention Window !ased /rioritiEation

= #eal8tie

= $est effort

0irtual collision resol&ed in fa&or of higher /riorit"

Extending DCF: EDCF

EDCF improves upon DCF by


183/298


EDCF improves upon DCF byprioritising trafc

Each trafc class can have adierent contention window

Dierent trafc classes touse dierent interramespaces, called rbitration

!nterrame "pace #!F"$

EDCF contention windowparameters

%o!& #priority$: '()*

F+& wo priority: )-(*.-)

%o!& wo priority:)-(*.-)

ccessto

channe

l

FTP fows + unprioritisedVoIP: larger contentionwindow

Prioritised VoIP calls : smallercontention window

7999 *+-.. 'uar"


184/298


7nfrastructure and ad hoc odes using DCF

Carrier 'ense Multi/le Access $inar" e:/onential !ackoff for collision a&oidance and

congestion control Acknowledgeents for relia!ilit"

6ower sa&e ode for energ" conser&ation Tie8!ound ser&ice using 6CF 'ignaling /ackets for a&oiding 9:/osed3;idden terinal

/ro!les, and for reser&ation

Mediu is reser&ed for the duration of the transission #T'8CT'in DCF

6ollsin 6CF


185/298


Mo!ile 76

Traditional #outing

A routing protocolsets u/ a routing tablein routers


186/298


#outing /rotocol is t"/icall" !ased on Distance80ector orLink8'tate algoriths

#outing and Mo!ilit"

Finding a /ath fro a source to a destination


187/298


Finding a /ath fro a source to a destination

7ssues Fre%uent route changes

= aount of data transferred !etween route changes a"

!e uch saller than traditional networks #oute changes a" !e related to host o&eent

Low !andwidth links

5oal of routing /rotocols decrease routing8related o&erhead find short routes

find Ksta!le routes (des/ite o!ilit")

Mo!ile 76 (#FC


188/298


!ased on 76 address network /refi: deterines the su!net

change of /h"sical su!net i/lies= change of 76 address (confor to new su!net), or

= s/ecial routing ta!le entries to forward /ackets to new su!net

Changing of 76 address DN' u/dates take to long tie

TC6 connections !reak securit" /ro!les

Changing entries in routing ta!les does not scale with the nu!er of o!ile hosts and fre%uent

changes in the location

securit" /ro!les

'olution re%uireents retain sae 76 address, use sae la"er /rotocols

authentication of registration essages,

Mo!ile 764 $asic 7dea


189/298


Ro+ter

%

Ro+ter

&

Ro+ter

!

6 M3

8omeaent

Mo!ile 764 $asic 7dea


190/298


Ro+ter

%

Ro+ter

&

Ro+ter

!

6 M3

8ome aent

7orein aent

move

9ackets are t+nneled

+sin I9 in I9

Mo!ile 764 Terinolog"

Mo!ile Node (MN)


191/298


node that o&es across networks without changing its 76 address

;oe Agent (;A)

host in the hoe network of the MN, t"/icall" a router

registers the location of the MN, tunnels 76 /acketsto the COA

Foreign Agent (FA)

host in the current foreign network of the MN, t"/icall" a router forwards tunneled /ackets to the MN, t"/icall" the default router for

MN

Care8of Address (COA)

address of the current tunnel end8/ointfor the MN (at FA or MN)

actual location of the MN fro an 76 /oint of &iew Corres/ondent Node (CN)

host with which MN is Kcorres/onding (TC6 connection)

Data transfer to the o!ile s"ste

8,

M3!


192/298


7nternet

sender

7,

M3

1ome network

*orein

network

recei&er

%

!

&

.- 'ender sends to the 76 address of MN,

;A interce/ts /acket (/ro:" A#6)- ;A tunnels /acket to COA, here FA,

!" enca/sulation


193/298


7nternet

recei&er

7,

M3

1ome network

*orein

network

sender

%

.- 'ender sends to the 76 address

of the recei&er as usual, FA works as default router

'ource4 'chiller

/3


194/298

Mo!ile 764 Other 7ssues

#e&erse Tunneling


195/298


firewalls /erit onl" Kto/ological correctK addresses a /acket fro the MN enca/sulated !" the FA is now

to/ological correct

O/tiiEations Triangular #outing

= ;A infors sender the current location of MN

Change of FA= new FA infors old FA to a&oid /acket loss, old FA now

forwards reaining /ackets to new FA


196/298


Mesh and Adhoc Networks

Multi8;o/ Wireless


197/298


Ma" need to tra&erse ulti/le links to reach destination

Mo!ilit" causes route changes

Mo!ile Ad ;oc Networks (MAN9T)

;ost o&eent fre%uent


198/298


;ost o&eent fre%uent

To/olog" change fre%uent

No cellular infrastructure- Multi8ho/ wireless links- Data ust !e routed &ia interediate nodes-

B

B

MAC in Ad hoc networks

7999 *+ .. DCF i t l


199/298


7999 *+-.. DCF is ost /o/ular 9as" a&aila!ilit"

*+-.. DCF4 Hses #T'8CT' to a&oid hidden terinal /ro!le

Hses AC> to achie&e relia!ilit"

*+-.. was designed for single8ho/ wireless Does not do well for ulti8ho/ ad hoc scenarios

#educed through/ut 9:/osed terinal /ro!le

9:/osed Terinal 6ro!le


200/298


A starts sending to $-

C senses carrier, finds ediu in use and has towait for A8R$ to end-

D is outside the range of A, therefore waiting is notnecessar"-

A and C are Ke:/osed terinals

, .

/D

Distance8&ector Link8state #outing

$oth assue router knows


201/298


$oth assue router knows

address of each neigh!or cost of reaching each neigh!or

$oth allow a router to deterine glo!al routinginforation !" talking to its neigh!ors

Distance &ector8 router knows cost to each destination

Link state8 router knows entire network to/olog" and

co/utes shortest /ath


202/298

Link 'tate #outing4 9:a/le


203/298


MAN9T #outing 6rotocols

6roacti&e /rotocolsT diti l di t i! t d h t t th t l


204/298


Traditional distri!uted shortest8/ath /rotocols

Maintain routes !etween e&er" host /air at all ties

$ased on /eriodic u/dates ;igh routing o&erhead

9:a/le4 D'D0 (destination se%uenced distance &ector)

#eacti&e /rotocols Deterine route if and when needed

'ource initiates route disco&er"

9:a/le4 D'# (d"naic source routing)

;"!rid /rotocols Ada/ti&e Co!ination of /roacti&e and reacti&e

9:a/le 4 I#6 (Eone routing /rotocol)

D"naic 'ource #outing (D'#)

#oute Disco&er" 6hase4


205/298


"

7nitiated !" source node ' that wants to send /acket todestination node D

#oute #e%uest (##91)floods through the network

9ach node appends own identiierwhen forwarding ##91

#oute #e/l" 6hase4

D on recei&ing the first ##91, sends a #oute #e/l" (##96) ##96 is sent on a route o!tained !" re&ersingthe route

a//ended to recei&ed ##91

##96 includes the routefro ' to D on which ##91 wasrecei&ed !" node D

Data Forwarding 6hase4 ' sends data to D !" source routingthrough interediate nodes


206/298


207/298

#oute disco&er" in D'#


208/298


.

,

6 0

7

8

E

D

/

G

I

J

=3ode 8 receives packet RR0@ *rom two nei1


209/298


.

,

6 0

7

8

E

D

/

G

I

J

L

=3ode D does not *orwardRR0@


210/298


.

,

6 0

7

8

E

D

/

G

I

J

L

M

3

2

RR09 607EDN

Represents RR09 control messae


211/298


212/298

D'D0

9ach node ad&ertises a onotonicall"


213/298


9ach node ad&ertises a onotonicall"increasing e&en se%uence nu!er for itself

When a node decides that a route is !roken, itincreents the se%uence nu!er of the route

and ad&ertises it with infinite etric Destination ad&ertises new se%uence nu!er


214/298

6rotocol Trade8offs

6roacti&e /rotocols Alwa"s aintain routes

Littl d l f t d t i ti


215/298


Little or no dela" for route deterination

Consue !andwidth to kee/ routes u/8to8date

Maintain routes which a" ne&er !e used

#eacti&e /rotocols Lower o&erhead since routes are deterined on deand

'ignificant dela" in route deterination 9/lo" flooding (glo!al search)

Control traffic a" !e !urst"

Which a//roach achie&es a !etter trade8off de/ends on the traffic ando!ilit" /atterns


216/298


TC6 o&er wireless

7/act of transission errors


217/298


Wireless channel a" ha&e !urst" rando errors

$urst errors a" cause tieout #ando errors a" cause fast retransit

TC6 cannot distinguish !etween /acket lossesdue to congestion and transission errors

Hnnecessaril" reduces congestion window Through/ut suffers


218/298

78TC64 '/lit connection a//roach

6er8TC6 connection state


219/298

Sridhar Iyer IIT Bombay 219wireless

/h"sical

link

network

trans/ort

a//lication

/h"sical

link

network

trans/ort

a//lication

/h"sical

link

network

trans/ort

a//licationr:t

6er TC6 connection state

TC6 connection TC6 connection

'noo/ /rotocol

$uffers data /ackets at the !ase station $'


220/298


to allow link la"er retransission When du/acks recei&ed !" $' fro M;

retransit on wireless link, if /acket /resent in !uffer

dro/ du/ack

6re&ents fast retransit at TC6 sender F;

FH MHBS

'noo/ /rotocol

6er TC6 connection state


221/298


F; M;$'wireless

/h"sical

link

networktrans/ort

a//lication

/h"sical

link

networktrans/ort

a//lication

/h"sical

link

networktrans/ort

a//lication

r:t

6er TC68connection state

TC6 connection

7/act of handoffs


222/298


'/lit connection a//roach hard state at !ase station ust !e o&ed to new !ase station

'noo/ /rotocol soft state need not !e o&ed

while the new !ase station !uilds new state, /acket losses a"

not !e reco&ered locall"

Fre%uent handoffs a /ro!le for schees that rel" onsignificant aount of hard3soft state at !ase stations

hard state should not !e lost soft state needs to !e recreated to !enefit /erforance


223/298

M8TC6

When a newack is recei&ed with recei&ers


224/298


ad&ertised window G +, the sender enters/ersist ode

'ender does not send an" data in /ersist ode e:ce/t when /ersist tier goes off

When a /ositi&e window ad&ertiseent isrecei&ed, sender e:its /ersist ode

On e:iting /ersist ode, #TOand cwndaresae as !efore the /ersist ode

TC6 in MAN9T

'e&eral factors affect TC6 /erforance in MAN9T4


225/298


Wireless transission errors a" cause fast retransit, which results in

= retransission of lost /acket

= reduction in congestion window

reducing congestion window in res/onse to errors isunnecessar"

Multi8ho/ routes on shared wireless ediu

Longer connections are at a disad&antage co/ared toshorter connections, !ecause the" ha&e to contend forwireless access at each ho/

#oute failures due to o!ilit"

7/act of Multi8ho/ Wireless 6aths

TC6 through/ut degrades with increase in nu!er of ho/s


226/298


6acket transission can occur on at ost one ho/aong three consecuti&e ho/s 7ncreasing the nu!er of ho/s fro . to , < results in increased

dela", and decreased through/ut

7ncreasing nu!er of ho/s !e"ond < allows siultaneoustransissions on ore than one link, howe&er,degradation continues due to contention !etween TC6Data and Acks tra&eling in o//osite directions

When nu!er of ho/s is large enough (R2), through/utsta!iliEes

mobi"ity ca(ses

7/act of Node Mo!ilit"T> thro(*h!(t de*rades )ith increase in mobi"ity b(t not a")ays


227/298


"in breaa*eres("tin* in ro(te

#ai"(re

T> data and acs

en ro(te discarded

T> sender times o(t-

Starts sendin* !acets a*ain

Ro(te is

re!aired

?o

thro(*h!(t

?o thro(*h!(t

des!ite ro(te re!air

:ar*er ro(te re!air

de"ays are es!ecia""y

harm#("


228/298

WiFi4 Manageent and 'ecurit"

Fi&e ke" areas (FCA6')4 Fault anageent

Network anageent


229/298


Ca/acit" anageent

Accounting(access) anageent

6erforance anageent

'ecurit" anageent

FCA6' at all la"ers of a stack (network,iddleware, a//s)

'ecurit" is the ain area of concern

Wireless Network Manageent

7n addition to the wired network issues,


230/298


,wireless network anageent needs toaddress soe s/ecific issues4

#oaing- 6ersistence of Mo!ile Hnits-

Lack of 'NM6 Agents in Mo!ile Hnits-

Mo!ile Adhoc Networks-

Wireless securit"


231/298


Threats

Disclosure of sensiti&e3confidential data


232/298


Denial of ser&ice (Do') HnauthoriEed access to wireless8ena!led

resources

6otential weakening of e:isting securit"easures on connected wired networks ands"stes

0ulnera!ilities

Wired 9%ui&alent 6ri&ac" (W96) encr"/tionstandard is weak


233/298


#adio signals susce/ti!le to Saing andinterference

6rotocol &ulnera!ilities allow

Network sessions to !e taken o&er !" an intruder

7nSection of in&alid data into network traffic

Network reconnaissance

Default configurations create Ko/en network

9:a/le4 The radio

0ulnera!ilities 8 .


234/298


signal fro awireless network cans/ill o&er fro the!uilding whereaccess /oints arelocated toneigh!oring!uildings, /arkinglots and /u!lic roads-


235/298

0ulnera!ilities 8


236/298


9:a/le4 These/acket traces showhighl" confidentialdata that can !eca/tured fro a

wireless network

Wireless securit" technologies

!!"ications

.ST #or transaction sec(rity

.S@%I% and #or sec(re emai"

.Aava sec(rity sandbo&es

.atabase sec(rity>an (se


237/298


%idd"e)are

ire"ess

:in

.802-11 sec(rity

.:: "in sec(rity

.SS: and T:S

.eb sec(rity +TTS I>S +TT +eaders

.ro&y server sec(rity

T>@I.IS> and )ir"ess ?.%obi"e I

hi*her "eve"services to

com!ensate

#or "o)er "ayers

Tradeo##s in!er#ormance

and sec(rity

'ecurit" and a&aila!ilit" The securit" ' is /ro&ided at the following le&els4

Le&el +4 no securit" s/ecified


238/298


Le&el .4 AuthoriEation and authentication of /rinci/als

Le&el 4 Auditing and encr"/tion (6ri&ac")

Le&el


239/298


Conduct risk assessents to deterine re%uiredle&el of securit"

Liit access to wireless networks through theuse of wireless securit" easures (i-e- *+-..i or

W6A) Maintain logical se/aration !etween wireless

and wired networks 6erfor wireless scans to identif" wireless

networks and a//lications (on a regular !asis) 9nforce wireless network /olicies


240/298

*+-.2 internals

8022 &ogical &in'

7999 *+ fail"


241/298


802!

"edium

#ccess

802!

$h%sical

8021 Bridging

802(

"edium

#ccess

802(

$h%sical

802)

"edium

#ccess

802)

$h%sical

802*

"edium

#ccess

802*

$h%sical

80211

"edium

#ccess

80211

$h%sical

80212

"edium

#ccess

80212

$h%sical

8021*

"edium

#ccess

8021*

$h%sical

+ata&in'

&a%er

$h%sical

&a%er

6ur/ose4

7999 *+-.2


242/298


to ena!le ra/id worldwide de/lo"ent of cost8effecti&e!road!and wireless access /roducts

*+-.24

consists of the $' ($ase 'tation) and ''s('u!scri!er 'tations)

All data traffic goes through the $', and the $' can control theallocation of !andwidth on the radio channel-

*+-.2 is a $andwidth on Deand s"ste-

'tandard s/ecifies4 The air interface, MAC (Mediu Access Control), 6;Y(6h"sical

la"er)

The s/ectru to !e used .+ 8 22 5;E licensed !and

7999 *+-.2


243/298


= Due to the short wa&elength

Line of sight is re%uired

Multi/ath is negligi!le

= Channels @ or * M;E wide are t"/ical= #aw data rates in e:cess of .+ M!/s

8.. 5;E

= 7999 'tandards Association 6roSect 6*+-.2a

= A//ro&ed as an 7999 standard on an , ++ 'rame %> 'rame %> 'rame

% b" b d

' based 802-16 %> rotoco"


247/298


Broadcast hase o)n"in hase%ovab"e bo(ndary

o)n"in

>arrier

C!"in

>arrier C!"in hase Random ccess hase

Broadcast Reserved

%ovab"e bo(ndary

Reserved >ontention

o)n"in

S(b#rame

:/% n/1

C:/% n/1

'rame n/1'rame n

Time re"evance o# +F and %> contro" in#ormation


248/298


C!"in

S(b#rame

Ro(nd tri! de"ay D TE!roc

Band)idth re(est s"ots

Downlink 'cheduling

#adio resources ha&e to !e scheduledaccording to the 1o'(1ualit" of 'er&ice)

t


249/298


/araeters Downlink scheduling4

the flows are si/l" ulti/le:ed

the standard scheduling algoriths can !e used= W##(Weighted #ound #o!in)= 0T(0irtual Tie)= WF1(Weighted Fair 1ueueing)= WFF1(Worst8case Fair weighted Fair 1ueueing)= D##(Deficit #ound #o!in)= DD##(Distri!uted Deficit #ound #o!in)


250/298

0T 0T 4 ais to eulate the TDM(Tie Di&ision Multi/le:ing) s"ste

connection . 4 reser&es @+] of the link !andwidth

connection , < 4 reser&es +] of the link !andwidth


251/298


>onnection 1

vera*e inter/arriva" G 2 (nits

>onnection 1


>onnection 2


>onnection 3vera*e inter/arriva" G 5 (nits

'irst/>ome/'irst/Served

service order

irt(a" times

irt(a" >"oc service order


252/298

$andwidth allocation and re%uest echaniss

The ethod !" which the ''('u!scri!er 'tation) canget the !andwidth re%uest essage to the $'($ase

't ti )


253/298


'tation) Hnicast

= When an '' is /olled indi&iduall", no e:/licit essage istransitted to /oll the ''-

= The '' is allocated, in the H68MA6(H/link Ma/), !andwidthsufficient for a !andwidth re%uest-

Multicast

= Certain C7D(Connection 7dentifier) are reser&ed for ulticastgrou/s and for !roadcast essages-

= An '' !elonging to the /olled grou/ a" re%uest !andwidthduring an" re%uest inter&al allocated to that C7D in the H68MA6

$roadcast

$andwidth allocation and re%uest echaniss

H5' 4 The $' /ro&ides fi:ed siEe !andwidth at /eriodic inter&als to H5'-

The '' is /rohi!ited fro sing an contention o//ort nities


254/298


The '' is /rohi!ited fro using an" contention o//ortunities- The $' shall not /ro&ide an" unicast re%uest o//ortunities-

rt6' The $' /ro&ides /eriodic unicast re%uest o//ortunities-

The '' is /rohi!ited fro using an" contention o//ortunities-

nrt6'

The $' /ro&ides tiel" unicast re%uest o//ortunities-

The '' is allowed to use contention re%uest o//ortunities-

$9 The '' is allowed to use contention re%uest o//ortunities-

$andwidth #e%uest85rant 6rotocol


255/298


$'

''.

''

.

-.

-

.- $' allocates !andwidth to ''sfor transitting !andwidthre%uest-

-. ''.transits !andwidthre%uests-

- ''transits !andwidth

re%uests-

?- $' allocates !andwidth to ''sfor transitting data !ased ontheir !andwidth re%uests-

$andwidth is also allocated forre%uesting ore !andwidth-@-. ''.transits data and

!andwidth re%uests-@- ''

transits data and

!andwidth re%uests-

?

@-.

@-

9:a/leTotal H/link $"tes G.++

'' and . $'

Fl H5' t6' t6' $9


256/298


''.Deands4

H5' G +

rt6' G .nrt6' G .@

$9 G


257/298



258/298


1o' and 0oice30ideo A//lications

$andwidth and a//lications

%DMA ! 655P#. %DMA !+++

7D57UMT.


259/298


.peed3 kbps

!5%DMA !,655P#.3 %DMA !+++

Transaction Processing

Messaging/Te8t Apps9oice/.M.

Location .er(ices

.till Image Transfers

Internet/9P" Access

Database Access

Document TransferLo& Quality 9ideo

Hig' Quality 9ideo

:,;


260/298


Band&idt'

#e1uirem

ents

Hig'

Lo&

Lo& Hig'Latency .ensiti(ity

Te8te=

mail

7=commerce7#P

9oice

TerminalMode

Internet/intranet

7=mail &it'Attac'ments

.treaming9ideo 9ideo

%onferencing

1ualit" of 'er&ice Network8le&el 1o'

Metrics include a&aila!le !3w, /acket loss rates, etc

9leents of a Network 1o' Architecture


261/298


9leents of a Network 1o' Architecture= 1o' s/ecification (traffic classes)

= #esource anageent and adission control

= 'er&ice &erification and traffic /olicing

= 6acket forwarding echaniss (filters, sha/ers, schedulers)

= 1o' routing A//lication8le&el 1o'

;ow well user e:/ectations are %ualitati&el" satisfied

Clear &oice, Sitter8free &ideo, etc

7/leented at a//lication8le&el4

= end8to8end /rotocols (#T63#TC6)

= a//lication8s/ecific encodings (F9C)

1o' !uilding !locks What kind of /reiu ser&ices

Service/SLA design

;ow uch resources


262/298


;ow uch resources admission control/provisioning

;ow to ensure network utiliEation, load !alancing QoS routing, traffic engineering

;ow to set aside resources in a distri!uted anner signaling, provisioning, policy

;ow to deli&er ser&ices when the traffic actuall" coes in traffic shaping, classification, scheduling

;ow to onitor %ualit", account and /rice these ser&ices network management, accounting, billing, pricing

1o' !ig /icture4 Control3Data /lanes

Control 6lane4 'ignaling Adission Control or

'LA (Contracting) 6ro&isioning3Traffic 9ngineering


263/298


7nternetwork or WANWorkstation

#outer

#outer

#outer

Workstation

Data 6lane4 Traffic conditioning (sha/ing, /olicing, arking etc) at the edge

Traffic Classification Claiing #eser&ed #esources (6er8ho/ $eha&ior8 6;$),

scheduling, !uffer anageent

'er&ices4 1ueuing3'cheduling

>"ass

Traffic

Classes

Traffic

Sources

HHHHHH


264/298


9:tra !its indicate the %ueue (class) for a /acket

;igh __ users get into high /riorit" %ueues, whichare in turn less /o/ulated GR lower dela" and

near8Eero likelihood of /acket dro/

>"ass >

>"ass B

>"ass HHHHHH

HHH

H

1o' and /ricing

1o' 6ricing Multi8class network re%uires differential /ricing

Oth i ll l t ! t i l


265/298


Otherwise all users select !est ser&ice class

'er&ice /ro&iders /ers/ecti&e Low cost (i/leentn, etering, accounting, !illing)

9ncourage efficient resource usage Co/etiti&eness and cost reco&er"

Hsers /ers/ecti&e Fairness and 'ta!ilit"

Trans/arenc" and 6redicta!ilit"

Controlla!ilit"

Multiedia a//lications

Audio


266/298


Audio '/eech (C9L6 t"/e codecs) Music (M6


267/298


%>@%e*aco

T> C

Iv4 Iv6

+-323 S

SI

RTS RS RT>

RT

+-261 %

:3@4 :5

Sonet T% thernet -34

Reservation %eas(rement

net)or9

"in9

!hysica"

!!"icationdaemon

9erne"

'ession 7nitiation 6rotocol ('76)

7n&ite users to sessions

Find the users current location


268/298


Find the user s current location atch with their ca/a!ilities and /references in order

to deli&er in&itation

Modif"3Terinate sessions

'ession Descri/tion 6rotocol ('D6) Hsed to s/ecif" client ca/a!ilities

9:a/le (client can su//ort M6958. &ideo codec,and M6< codecs)

'76 co/onents Hser Agent Client (HAC)

9nd s"stes 'end '76 re%uests

Hser Agent 'er&er (HA')


269/298


Hser Agent 'er&er (HA') Listens for call re%uests

6ro/ts user or e:ecutes /rogra to deterine res/onse

Hser Agent4 HAC /lus HA'

#egistrar #ecei&es registrations regarding current user locations

#edirect 'er&er

#edirects users to tr" other ser&er 6ro:" 'er&er

'76 architecture

6I9 Redirect6

Re+est

Response


270/298


%

!

&

"

'

#

$

?

%

%%

%!

6I9 /lient

6erver

6I9 9roK6I9 9roK

6I9 /lient

(Cser ,ent 6erver)

2ocation 6ervice

%&

%"

p

Media

'76 call flow e:a/le

CSR CSR BR$JF R$JF

I?IT407 th ti t


271/298


407 ro&y (thenticate

>K

I?IT

I?ITI?IT

180 Rin*in*100 Tryin*

100 Tryin*

180 Rin*in*180 Rin*in* 200 $K 200 $K

200 $K

>K>K

>K

B$T+ F RT

BFBF

BF

200 $K 200 $K 200 $K

;-


272/298


6art of larger set of standards (;-


273/298


;-


274/298


5atekee/er4 ost i/ortant co/onent which /ro&ides call control ser&ices

5atewa"4 an o/tional eleent which /ro&ides translation functions

!etween ;-


275/298


Adission control 6erission to co/lete call

Can a//l" !andwidth liits

Method to control LAN traffic

Call signaling3anageent3re/orting3logging

Manageent of 5atewa"

;-


276/298


- 5> resol&es $o! to 76 address through ;-


277/298


#T6 s/ecifies coon a//lication functions

Tailored through odifications and3or additions to theheaders

#T6 consists of a data and a control /art The data /art of #T6 is a thin /rotocol The control /art of #T6 is called #TC6

= %ualit"8of8ser&ice feed!ack fro recei&ers

= snchroniEation su//ort for edia streas

#T6 (contd)

#T6 ser&ices /a"load t"/e identification

se%uence nu!ering tiesta/ing


278/298


se%uence nu!ering, tiesta/ing

deli&er" onitoring, o/tional i:ing3translation-

HD6 for ulti/le:ing and checksu ser&ices #T6 does not /ro&ide

echaniss to ensure %ualit"8of8ser&ice, guaranteedeli&er" or /re&ent out8of8order deli&er" or loss


279/298


Trends

irelessAccess "et&ork

5ate&ay

5ate&ay

Telep'one

"et&ork

%ore "et&ork

Programmable. fts itc'

Programmable.ofts&itc'


280/298


Mobile Access#outer

Mobile Access#outer

IPBase .tations

IPBase .tations

User Profiles ?Aut'entication

-HL#0

)5 AirInterface

>ired Access

*+!,

IP Intranet

IP Intranet

.ofts&itc'.ofts&itc'

Application.er(er

Application.er(er

*+!,

AccessPoint

AccessPoint

AccessPoint

AccessPoint

Internet

O&erla" Networks 8 the glo!al goal

regional

integration of heterogeneous fi:ed ando!ile networks with &ar"ingtransission characteristics


281/298


g

etro/olitan area

ca/us8!ased

in8house

&erticalhando&er

horiEontalhando&er

Future o!ile and wireless networks

7/ro&ed radio technolog" and antennas sart antennas, !ea foring, ulti/le8in/ut ulti/le8out/ut

(M7MO)di i i lti l t i it ! fit f


282/298


= s/ace di&ision ulti/le: to increase ca/acit", !enefit froulti/ath

software defined radios ('D#)

= use of different air interfaces, download new odulation3coding

= re%uires a lot of /rocessing /ower d"naic s/ectru allocation

= s/ectru on deand results in higher o&erall ca/acit"

Core network con&ergence 768!ased, %ualit" of ser&ice, o!ile 76

Ad8hoc technologies s/ontaneous counication, /ower sa&ing, redundanc"

#eferences A-'- Tanen!au- Co/uter Networks- 6earson 9ducation, ++


283/298


",

*+-.. Wireless LAN, 7999 standards, www-ieee-org

0arious #FCs4 #FC ++, @+.,


284/298


Other Tutorials at4 www-it-iit!-ac-in3 sri

Contact Details4

'ridhar 7"er'chool of 7nforation Technolog"

77T $o!a", 6owai, Mu!ai ?++ +2

6hone4 .88@28+@9ail4 sriit-iit!-ac-in


285/298


9:tra 'lides4 A6 'etu/ 'ite 'ur&e"


286/298



287/298



288/298



289/298



290/298



291/298



292/298



293/298



294/298



295/298



296/298



297/298



298/298

Date post:	28-Feb-2018
Category:	Documents
Upload:	pratiharmukesh
View:	214 times
Download:	0 times

Course on Wireless 05

Documents