Chuong 6 - Cac mang khong day và di dong

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  • Cc mng khng dy v di ng 1

    Chng 6Cc mng khng dy v di ng

    Computer Networking: A Top Down Approach Featuring the Internet, 3rd edition. Jim Kurose, Keith RossAddison-Wesley, July 2004.

    All material copyright 1992006J.F Kurose and K.W. Ross, All Rights Reserved

    Slide ny c bin dch sang ting Vit theo s cho php ca cc tc gi

  • Cc mng khng dy v di ng 2

    Chng 6: Ni dung trnh by

    6.1 Gii thiu Wireless

    6.2 Cc kt ni, c tnh

    CDMA

    6.3 IEEE 802.11 wireless LANs (wi-fi)

    6.4 Truy cp Cellular Internet kin trc

    cc chun (v d: GSM)

    Tnh di ng

    6.5 Cc nguyn l: nh a ch v routing n cc ngi dng di ng

    6.6 Mobile IP

    6.7 Qun l s di ng trong cc mng cellular

    6.8 Tnh di ng v cc giao thc lp cao hn

  • 6.1 Gii thiu Wireless

    Cc mng khng dy v di ng 3

  • Cc mng khng dy v di ng 4

    Gii thiu

    Background:

    s lng thu bao in thoi di ng (khng dy) ln hn c dy

    mng: my tnh xch tay, palm, PDA, in thoi Internet s truy cp Internet bt k thi im no

    2 thch thc quan trng (khc nhau) truyn thng trn cc kt ni khng dy (wireless)

    qun l ngi dng di ng, l ngi s thay i v tr kt ni vi mng

  • 6.2 Cc kt ni, c tnh

    Cc mng khng dy v di ng 5

  • Cc mng khng dy v di ng 6

    Cc thnh phn ca 1 mng di ng

    h tng mng

    wireless hosts

    laptop, PDA, IP phone

    chy cc ng dng

    c th c nh hoc di ng wireless khng c

    ngha lun phi di ng

  • Cc mng khng dy v di ng 7

    Cc thnh phn ca 1 mng di ng

    trm c s

    c trng bi kt ni vo mng c dy (wired)

    relay - p ng vic chuyn cc gi gia mng c dy v host khng dy trong vng

    v d: cc access point 802.11

    h tng mng

  • Cc mng khng dy v di ng 8

    Cc thnh phn ca 1 mng di ng

    kt ni wireless

    c trng bi dng kt ni khng dy n trm c s

    cng dng nh kt ni backbone

    giao thc a truy cp

    cc tc truyn dliu, khong cch truyn khc nhau

    h tng mng

  • Cc mng khng dy v di ng 9

    Cc c tnh ca cc chun kt ni khng dy

    384 Kbps

    56 Kbps

    54 Mbps

    5-11 Mbps

    1 Mbps802.15

    802.11b

    802.11{a,g}

    IS-95 CDMA, GSM

    UMTS/WCDMA, CDMA2000

    .11 p-to-p link

    2G

    3G

    trongnh

    10 30m

    bn ngoi

    50 200m

    vngtrung bnh

    200m 4Km

    vng khongcch xa

    5Km 20Km

  • Cc mng khng dy v di ng 10

    Cc thnh phn ca 1 mng di ng

    kiu c s h tng mng

    trm c s kt ni khng dy vi mng c dy

    handoff: linh hot thay i trm c s cung cp kt ni n mng c dy

    h tng mng

  • Cc mng khng dy v di ng 11

    Cc thnh phn ca 1 mng di ng

    ch ad-hoc

    khng c cc trm cs

    cc nt ch c th lin lc vi nhau trong vng kt ni

    cc nt t t chc vo trong 1 mng: route gia chng

  • Cc mng khng dy v di ng 12

    cc c tnh ca kt ni khng dy

    Khc bit vi c ni dy .

    cng tn hiu gim: tn hiu radio gim khi lan truyn trn ng (mt mt trn ng truyn)

    nhiu bi cc ngun khc: tn s mng khng dy chun ha (vd: 2.4GHz) c nhiu thit bdng, cc thit b gy nhiu ln nhau

    lan truyn nhiu hng

    . lm cho truyn thng qua kt ni khng dy thm nhiu kh khn (thm ch c trong trng hp im-im)

  • Cc mng khng dy v di ng 13

    cc c tnh ca kt ni khng dynhiu ngi gi v nhiu ngi nhn khng dy to ra

    thm cc vn (hn c trng hp a truy cp):

    AB

    C

    vn tim n u cui B, A nghe thy nhau

    B, C nghe thy nhau

    A, C khng nghe thy nhau

    ngha l A, C khng bit v s can thip ca B

    A B C

    cng tn hiu ca A

    space

    cng tn hiu ca C

    gim mc tn hiu: B, A nghe thy nhau

    B, C nghe thy nhau

    A, C khng nghe thy nhau d giao thoa ti B

  • Cc mng khng dy v di ng 14

    Code Division Multiple Access (CDMA)

    dng trong mt s chun knh pht khng dy (cellular, v tinh)

    m duy nht gn cho mi user, ngha l phn hoch tp m

    tt c user chia s cng tn s, nhng mi user c tin trnh (m) ring m ha d liu

    tn hiu m ha = (tn hiu gc) X (tin trnh ring)

    gii m: tch trong ca tn hiu m ha v tin trnh ring

    cho php nhiu user cng tn ti v truyn ng thi vi nhiu ti thiu (nu cc m l trc giao)

  • Cc mng khng dy v di ng 15

    CDMA m ha/gii m

    slot 1 slot 0

    d1 = -1

    1 1 1 1

    1- 1- 1- 1-

    Zi,m= di.cm

    d0 = 1

    1 1 1 1

    1- 1- 1- 1-

    1 1 1 1

    1- 1- 1- 1-

    1 1 11

    1-1- 1- 1-

    slot 0channeloutput

    slot 1channeloutput

    channel output Zi,m

    bn gi

    code

    databits

    slot 1 slot 0

    d1 = -1

    d0 = 1

    1 1 1 1

    1- 1- 1- 1-

    1 1 1 1

    1- 1- 1- 1-

    1 1 1 1

    1- 1- 1- 1-

    1 1 11

    1-1- 1- 1-

    slot 0channeloutput

    slot 1channeloutputbn nhn

    code

    receivedinput

    Di = SZi,m.cmm=1

    M

    M

  • Cc mng khng dy v di ng 16

    CDMA: nhiu do 2 bn gi

  • 6.3 Cc LAN khng dy - IEEE 802.11 (wi-fi)

    Cc mng khng dy v di ng 17

  • Cc mng khng dy v di ng 18

    IEEE 802.11 Wireless LAN

    802.11b ph sng radio khng c

    licence, vng t 2.4-5 GHz

    tc ln n 11 Mbps

    ph lan truyn trc tip trong lp physical

    tt c cc host dng cng m

    ph bin rng ri, dng cc trm c s

    802.11a vng t 5-6 GHz

    tc ln n 54 Mbps

    802.11g vng t 2.4-5 GHz

    tc ln n 54 Mbps

    tt c u dng CSMA/CA cho c cha truy cp

    tt c u c trm cs v cc phin bn mng ad-hoc

  • Cc mng khng dy v di ng 19

    Kin trc 802.11 LAN

    host khng dy truyn thng vi trm c s

    trm c s = access point (AP)

    Basic Service Set (BSS)(gi l cell) cha:

    cc host khng dy

    access point (AP

    ch ad hoc: ch c cc host

    BSS 1

    BSS 2

    Internet

    hub, switchhoc router

    AP

    AP

  • Cc mng khng dy v di ng 20

    802.11: cc knh, s lin kt

    802.11b: ph t 2.4GHz-2.485GHz c chia thnh 11 knh vi tn s khc nhau

    qun tr AP chn tn s cho AP

    nhiu c th: knh c th ging vi AP bn cnh!

    host: phi lin kt vi 1 AP qut cc knh, lng nghe cc frame bo hiu

    cha tn ca AP (SSID) v cc a ch MAC

    chn AP lin kt

    c th phi thc hin vic chng thc (xem chng 8)

    thng s chy DHCP ly a ch IP trong subnet

  • Cc mng khng dy v di ng 21

    IEEE 802.11: a truy cp

    trnh tranh chp: cc nt truyn cng thi im

    802.11: CSMA cm nhn trc khi truyn khng xung t vi qu trnh ang truyn ca nt khc

    802.11: khng pht hin tranh chp! kh khn cm nhn tranh chp khi truyn v cc tn hiu

    nhn b yu

    khng th cm nhn tt c cc tranh chp trong mi trng hp: cc u cui che khut, tn hiu yu

    mc tiu: trnh cc tranh chp: CSMA/C(ollision)A(voidance)

    AB

    CA B C

    cng tn hiu ca A

    space

    cng tn hiu ca C

  • Cc mng khng dy v di ng 22

    Giao thc IEEE 802.11 MAC: CSMA/CA

    Bn gi 802.11

    1 Nu cm nhn knh rnh th truyn ton bframe (khng pht hin tranh chp)

    2 Nu knh bn th:

    khi to thi gian ch i ngu nhin

    b nh th gim xung trong khi knh rnh

    truyn khi b nh th kt thc

    nu khng c ACK, tng thi gian ch i ngu nhin, lp li bc 2

    Bn nhn 802.11

    - Nu frame nhn tt (OK)tr li tn hiu ACK

    Bn gi Bn nhn

    DIFS

    data

    SIFS

    ACK

  • Cc mng khng dy v di ng 23

    Trnh cc tranh chp (tt)

    tng: cho php bn gi c ng k trc knh hn l truy cp ngu nhin cc frame d liu: trnh tranh chp ca vi cc frame di

    u tin bn gi gi cc gi request-to-send (RTS) nh n trm c s dng CSMA

    cc RTS c th vn xung t vi cc ci khc (nhng t)

    trm c s broadcasts tn hiu clear-to-send (CTS) tr li cho RTS

    RTS c tt c cc nt lng nghe

    bn gi truyn frame d liu

    cc trm khc tr hon vic truyn

    Trnh tranh chp trit dng cc gi ng k trc nh!

  • Cc mng khng dy v di ng 24

    Trnh tranh chp: trao i RTS-CTS

    APA B

    time

    DATA (A)

    tranh chp ng k trc

    tr hon

  • Cc mng khng dy v di ng 25

    framecontrol

    durationaddress

    1address

    2address

    4address

    3payload CRC

    2 2 6 6 6 2 6 0 - 2312 4

    seqcontrol

    802.11 frame: nh a ch

    a ch 2: a ch MAC ca host hoc AP truyn frame ny

    a ch 1: a chMAC ca host hoc AP nhn frame ny

    a ch 3: a ch MAC ca router m AP gn vo

    a ch 4: ch dng trong ch ad-hoc

  • Cc mng khng dy v di ng 26

    Internetrouter

    AP

    H1 R1

    AP MAC addr H1 MAC addr R1 MAC addr

    address 1 address 2 address 3

    802.11 frame

    R1 MAC addr AP MAC addr

    dest. address source address

    802.3 frame

    802.11 frame: nh a ch

  • Cc mng khng dy v di ng 27

    framecontrol

    durationaddress

    1address

    2address

    4address

    3payload CRC

    2 2 6 6 6 2 6 0 - 2312 4

    seqcontrol

    TypeFromAP

    SubtypeToAP

    More frag

    WEPMoredata

    Powermgt

    Retry RsvdProtocolversion

    2 2 4 1 1 1 1 1 11 1

    802.11 frame: nh a chkhong thi gian truyn ng k (RTS/CTS)

    s tin trnh frame(dnh cho ARQ tin cy)

    kiu frame(RTS, CTS, ACK, d liu)

  • Cc mng khng dy v di ng 28

    hub hocswitch

    AP 2

    AP 1

    H1 BBS 2

    BBS 1

    802.11: tnh di ng trong cng subnet

    router H1 duy tr trong cng

    IP subnet: a ch IP cng lm ging vy

    switch: AP no lin kt vi H1? t hc (Ch. 5): switch

    s nhn thy frame tH1 v nh port no dng chm n H1

  • Cc mng khng dy v di ng 29

    Mbn knhbao trm

    S

    SS

    P

    P

    P

    P

    M

    S

    thit b master

    thit b slaver

    thit b nh v (khng hot ng)P

    802.15: mng vng c nhn

    ng knh < 10 m

    thay th cho cc loi cp (mouse, keyboard, headphones)

    ad hoc: khng thit b cnh

    master/slaver: cc slaver yu cu quyn gi

    (n master)

    master chp nhn cc yu cu

    802.15: pht trin tBluetooth di tn s radio t 2.4-2.5

    GHz

    tc ln n 721 kbps

  • 6.4 Truy cp Cellular Internet

    Cc mng khng dy v di ng 30

  • Cc mng khng dy v di ng 31

    Mobile Switching

    Center

    mng in thoi cng cng &Internet

    Mobile Switching

    Center

    Cc thnh phn ca kin trc mng cellular

    kt ni cc cell trong mt vng rng ln qun l cc cuc gi iu khin

    MSC

    bao trm mt vng trm c s ging vi 802.11 AP nhng user gn vo mng thng qua trm c s air-interface: giao thc lp physical v link gia thit b di ng & trm c s

    cell

    mng ni dy

  • Cc mng khng dy v di ng 32

    cc mng Cellular: hop u tin

    2 k thut chia s ph sng radio t di ng n trm c s

    FDMA/TDMA kt hp: chia ph thnh cc knh tn s, mi knh c chia thnh cc time slot

    CDMA: code division multiple access

    cc di tn s

    cc slot thi gian

  • Cc mng khng dy v di ng 33

    cc chun Cellular: tng quan

    cc h thng 2G: cc knh ting

    IS-136 TDMA: FDMA/TDMA kt hp (Bc M)

    GSM (global system for mobile communications): FDMA/TDMA kt hp rt ph bin

    IS-95 CDMA: code division multiple access

    GSM

  • Cc mng khng dy v di ng 34

    cc chun Cellular: tng quan

    cc h thng 2.5 G: cc knh ting & d liu vi nhng ngi khng th ch i dch v 3G: 2G m

    rng

    general packet radio service (GPRS) pht trin t GSM

    d liu c gi trn nhiu knh

    enhanced data rates for global evolution (EDGE) cng pht trin t GSM, dng iu ch tng cng

    ngy nay, tc c nng ln n 384K

    CDMA-2000 (giai on 1) ngy nay, tc c nng ln n 144K

    pht trin t IS-95

  • Cc mng khng dy v di ng 35

    cc chun Cellular: tng quan

    cc h thng 3G: knh ting / d liu

    Universal Mobile Telecommunications Service (UMTS)

    th h GSM k tip, nhng dng CDMA

    CDMA-2000

    .. cn nhiu ti th v hn v mng di ng

  • 6.5 Cc nguyn l: nh a ch v routing n cc ngi

    dng di ng

    Cc mng khng dy v di ng 36

  • Cc mng khng dy v di ng 37

    Di ng l g?

    s phn b theo tnh cht ca mng di ng:

    khng di ng tnh di ng cao

    user khng dy di ng, dng cng AP

    user di ng, truyn thng qua nhiu AP trong khi vn ginguyn cc kt ni (dng in thoi cell)

    user di ng, kt ni/hy kt ni tmng dng DHCP.

  • Cc mng khng dy v di ng 38

    Di ng l g?

    mng gia nh: gia nh bn vng ca cc thit bdi ng(vd: 128.119.40.186/24)

    a ch c nh: a chtrong mng gia nh, c th lun lun dng chm n mng di ngvd: 128.119.40.186

    home agent: thc th s hon tt cc chc nng di ng

    WAN

    correspondent

  • Cc mng khng dy v di ng 39

    Di ng l g?

    Care-of-address: a chtrong visited network.(vd: 79.129.13.2)

    WAN

    visited network: l mng trong thit b di ng ang thng tr (vd: 79.129.13/24)

    a ch c nh: gi nguyn, khng i (vd: 128.119.40.186)

    foreign agent: l thc th trong visited network thc hin nhng chc nng di ngcorrespondent: c

    nhu cu truyn thng vi mng di ng

  • Cc mng khng dy v di ng 40

    Lm th no lin lc vi thit b di ng khc?

    tm trong tt c danh b in thoi?

    gi cho cha m ca bn y?

    ch i bn y s cho bn bit l ang u?

    Ti mun bit Alice ang u?

    Kho st trng hp 1 ngi bn thng xuyn thay i a ch, lm sao tm?

  • Cc mng khng dy v di ng 41

    Cc cch tip cn

    cho routing qun l: Thng bo a ch c nh ca thit b di ng bng cch trao i bng routing

    bng routing ny s ch cho bit thit b di ng ang u

    khng thay i g h thng u cui

    cho h thng u cui qun l: routing khng trc tip: truyn thng t

    correspondent n thit b di ng thng qua home agent, sau chuyn n thit b xa

    routing trc tip: correspondent ly a ch ngoi ca thit b di ng, gi trc tip n thit b di ng

  • Cc mng khng dy v di ng 42

    Cc cch tip cn

    cho routing qun l: Thng bo a ch c nh ca thit b di ng bng cch trao i bng routing

    bng routing ny s ch cho bit thit b di ng ang u

    khng thay i g h thng u cui

    cho h thng u cui qun l: routing gin tip: truyn thng t correspondent

    n thit b di ng thng qua home agent, sau chuyn n thit b xa

    routing trc tip: correspondent ly a ch ngoi ca thit b di ng, gi trc tip n thit b di ng

    khng linh hot vi hng triu

    thit b di ng

  • Cc mng khng dy v di ng 43

    ng nhp

    Kt qu cui cng:

    Foreign agent bit v thit b di ng

    Home agent bit v tr ca thit b di ng

    WAN

    home networkvisited network

    1

    thit b di ng tip xc vi foreign agent ng nhp vo visited network

    2

    foreign agent tip xc vi agent home: thit b di ng ny thng tr trong mng ca ti

  • Cc mng khng dy v di ng 44

    Tnh di ng thng qua Routing gin tip

    wide area network

    homenetwork

    visitednetwork

    3

    2

    41

    correspondent nh vcc gi dng a chhome ca thit b di ng

    home agent chn cc gi, chuyn tip n foreign agent

    foreign agent nhn cc gi, chuyn tip n thit b di ng

    thit b di ng phn hi trc tip cho correspondent

  • Cc mng khng dy v di ng 45

    Routing gin tip: ch thch

    Thit b di ng dng 2 a ch:

    a ch c nh: dng bi correspondent (v tr ca thit b trong sut i vi correspondent)

    care-of-address: dng bi home agent chuyn tip cc datagrams n thit b di ng

    chnh cc thit b di ng c th hon thnh cc chc nng ca foreign agent

    routing tam gic: correspondent-home-network-thit b di ng

    khng hiu qu khi

    correspondent, thit b

    di ng nm cng mng

  • Cc mng khng dy v di ng 46

    Routing gin tip: di chuyn gia cc mng

    gi s user di ng di chuyn n mng khc ng k vi foreign agent mi

    foreign agent mi ng k vi home agent

    home agent cp nht care-of-address cho thit bdi ng

    cc gi tip tc c chuyn tip n thit b di ng (nhng vi care-of-address mi)

    vic thay i mng l trong sut: cc kt ni vn c duy tr!

  • Cc mng khng dy v di ng 47

    Di ng thng qua Routing trc tip

    WAN

    homenetwork

    visitednetwork

    4

    2

    41correspondent yu cu, nhn foreign address ca thit bdi ng

    correspondent chuyn tip n foreign agent

    foreign agent nhn cc gi, chuyn tip n thit b di ng

    thit b di ng phn hi trc tip vi correspondent

    3

  • Cc mng khng dy v di ng 48

    Routing trc tip: cc ch thch

    khc phc vn routing tam gic

    khng trong sut i vi correspondent:correspondent phi ly care-of-address thome agent

    iu g xy ra nu thit b di ng thay i visited network?

  • Cc mng khng dy v di ng 49

    WAN

    1

    foreign net visited ngay lc phin lm vic bt uanchor

    foreignagent

    2

    4

    foreignagent mi

    35

    correspondentagent

    correspondent

    foreignnetwork mi

    Accommodating mobility with direct routing

    anchor foreign agent (FA): FA trong visited network u tin

    d liu lun lun u tin route ti anchor FA

    khi thit b di ng di chuyn: FA mi thu xp d liu chuyn tip t FA c (dy chuyn)

  • 6.6 Mobile IP

    6.7 Qun l s di ng trong cc mng cellular

    6.8 Tnh di ng v cc giao thc lp cao hn

    Cc mng khng dy v di ng 50

  • Cc mng khng dy v di ng 51

    Mobile IP

    RFC 3220

    c nhiu c tnh m chng ta va xem qua:

    home agents, foreign agents, ng k foreign-agent, care-of-addresses, ng gi (gi-bn trong-gi)

    3 thnh phn cn chun ha:

    routing gin tip cc datagrams

    pht hin agent

    ng k vi home agent

  • Cc mng khng dy v di ng 52

    Mobile IP: routing gin tip

    a ch c nh: 128.119.40.186

    Care-of address: 79.129.13.2

    ch: 128.119.40.186

    gi c gi bi correspondent

    ch: 79.129.13.2 ch: 128.119.40.186

    gi c gi bi home agent n foreign agent: mt gi trong gi

    dest: 128.119.40.186

    gi foreign-agent-n-thit b

  • Cc mng khng dy v di ng 53

    Mobile IP: pht hin agent

    thng bo agent: cc foreign/home agents thng bo dch v bng cch broadcasting cc thng ip ICMP (typefield = 9)

    RBHFMGV bits

    reserved

    type = 16

    type = 9 code = 0 = 9

    checksum

    router address

    standard ICMP fields

    mobility agent advertisement

    extension

    length sequence #

    registration lifetime

    0 or more care-of-addresses

    0 8 16 24

    R bit: yu cu ng k

    H,F bits: home / foreign agent

  • Cc mng khng dy v di ng 54

    Mobile IP: v d ng k

    visited network: 79.129.13/24

    home agent

    HA: 128.119.40.7 foreign agent

    COA: 79.129.13.2

    COA: 79.129.13.2 .

    ICMP agent adv. Mobile agent

    MA: 128.119.40.186

    registration req.

    COA: 79.129.13.2 HA: 128.119.40.7 MA: 128.119.40.186 Lifetime: 9999 identification:714 .

    registration req.

    COA: 79.129.13.2 HA: 128.119.40.7 MA: 128.119.40.186 Lifetime: 9999 identification: 714 encapsulation format .

    registration reply

    HA: 128.119.40.7 MA: 128.119.40.186 Lifetime: 4999 Identification: 714 encapsulation format .

    registration reply

    HA: 128.119.40.7 MA: 128.119.40.186 Lifetime: 4999 Identification: 714 .

    time

  • Cc mng khng dy v di ng 55

    Cc thnh phn ca kin trc mng cellular

    correspondent

    MSC

    MSC

    MSCMSC

    MSC

    mng in thoi ni dy cng cng

    cc mng cellular khc nhau, iu hnh bi cc nh cung cp khc nhau

  • Cc mng khng dy v di ng 56

    Qun l tnh di ng trong cc mng cellular

    home network: mng cc nh cung cp cellular m bn ng k

    home location register (HLR): c s d liu trong mng home cha s lng cell phone cnh, thng tin khc (cc dch v, ha n)

    visited network: mng trong thit b di ng thng tr

    visitor location register (VLR): c s d liu vi cc bn ghi cho mi user hin hnh

    c th l home network

  • Cc mng khng dy v di ng 57

    mng in thoi chuyn mch cng cng

    mobileuser

    homeMobile

    Switching Center

    HLRhome network

    visitednetwork

    correspondent

    Mobile Switching

    Center

    VLR

    GSM: routing gin tip n thit b di ng

    1 cuc gi c route n home network

    2

    home MSC tra cu HLR,ly s hiu roaming ca thit b di ng trong visited network

    3

    home MSC thit lp chiu th 2 ca cuc gi n MSC trong visited network

    4

    MSC trong visited network hon ttcuc gi thng qua trm c s n thit b di ng

  • Cc mng khng dy v di ng 58

    Mobile Switching

    Center

    VLR

    BSS cBSS mi

    routingc

    routingmi

    GSM: handoff vi MSC

    mc tiu Handoff: route cuc gi thng qua trm c s mi (khng gin on)

    l do handoff:

    tn hiu mnh hn n/t BSS mi (kt ni lin tc, t tiu hao nng lng)

    cn bng ti: gii phng knh trong BSS hin ti

    GSM khng ni ti sao thc hin handoff (chnh sch), chbit cch lm (c ch)

    handoff c khi to bi BSS c

  • Cc mng khng dy v di ng 59

    Mobile Switching

    Center

    VLR

    BSS c

    1

    3

    24

    5 6

    78

    GSM: handoff vi MSC

    BSS mi

    1. BSS c thng bo MSC handoff, cung cp danh sch cc BSS 1+ mi

    2. MSC thit lp ng (cp pht ti nguyn) n BSS mi

    3. BSS mi cp pht knh radio cho user di ng

    4. BSS mi thng bo cho MSC, BSS c: sn sng

    5. BSS c ni vi thit b di ng: thc hin handoff vi BSS mi

    6. thit b di ng, BSS mi thng bo kch hot knh mi

    7. thit b di ng thng bo vi BSS mi n MSC: handoff hon tt. MSC route li cuc gi

    8 MSC-c-BSS gii phng ti nguyn

  • Cc mng khng dy v di ng 60

    home network

    Home MSC

    PSTN

    correspondent

    MSC

    anchor MSC

    MSCMSC

    (a) trc khi handoff

    GSM: handoff gia cc MSC

    anchor MSC: MSC u tin trong sut cuc gi cuc gi duy tr route

    thng qua anchor MSC

    cc MSC mi thm vo cui dy chuyn MSC ging nh thit b di ng di chuyn vo MSC mi

    IS-41 cho php ty chn ti thiu ha thu ngn ng i gia cc dy chuyn MSC

  • Cc mng khng dy v di ng 61

    home network

    Home MSC

    PSTN

    correspondent

    MSC

    anchor MSC

    MSCMSC

    (b) sau khi handoff

    GSM: handoff between MSCs

    anchor MSC: MSC u tin trong sut cuc gi cuc gi duy tr route

    thng qua anchor MSC

    cc MSC mi thm vo cui dy chuyn MSC ging nh thit b di ng di chuyn vo MSC mi

    IS-41 cho php ty chn ti thiu ha thu ngn ng i gia cc dy chuyn MSC

  • Cc mng khng dy v di ng 62

    GSM vi Mobile IP

    GSM Ch thch Mobile IPHome system Mng cha cc s in thoi c nh ca user

    di ngHome network

    Gateway Mobile Switching Center, home MSC. HLR

    Home MSC: im tip xc ly c a ch route. HLR: c s d liu trong home MSC cha s t c nh, thng tin b sung, v tr hin ti ca user di ng

    Home agent

    Visited System Mng khc vi h thng home, trong user di ng ang thng tr

    Visited network

    Visited Mobile services Switching Center.Visitor Location Record (VLR)

    Visited Mobile: p ng cho vic thit lp cuc gi n/t thit b di ng trong cc cell kt ni vi MSC. VLR: dng ng k tm thi trong h thng visited, cha thng tin ng k ca mi user

    Foreign agent

    Mobile Station Roaming Number (MSRN), roaming number

    a ch c th route cho mi on cuc gi t gia home MSC v visited MSC,

    Care-of-address

  • Cc mng khng dy v di ng 63

    Khng dy, di ng: nh hng n cc giao thc lp cao hn

    nh hng s l ti thiu

    m hnh dch v hng hiu qu tt nht gi nguyn khng thay i

    TCP v UDP c th (v ang hin thc) chy trn mng khng dy, di ng

    nhng hiu qu:

    gi mt/tr v cc li bit (cc gi b hy, tr v truyn li) v handoff

    tr lm suy gim lu thng thi gian thc

    bng thng gii hn ca cc kt ni khng dy