Dịch vụ VPLS và BGP MPLS VPN

CONG NGHE VIEN THONG<br /> <br /> <br /> <br /> <br /> DICHVU<br /> V P L S VA BGP<br /> MPLS VPN<br /> <br /> Tran Quoc Khanh<br /> <br /> He thdng mang truyen tii mdi dua tren cdng nghe chuyen mach IP lop 3. Nd cho phep mot mach io<br /> Ethernet, IP vi MPLS dip img nhu cau ket ndi mang hoac dudng ham duge tao tren mang dudng true IP<br /> ndi bo eie doanh nghiep, thay the cie kieu ket ndi vi du Ueu ed the dugc chuyin mach don giin vi<br /> truyen thong bang thdng han hep, chi phi gia thanh nhanh chdng qua dudng him mi khdng cin phin<br /> eao. Vdi IP/MPLS, dich vu mang heng ao (VPN) la tich eie gdi tin rieng hoac tinh toin dinh tuyin din<br /> giai phip ket ndi mang linh hoat, chi phi thap, hd eie nut mang khic. MPLS ciing hd trg chit lugng<br /> trg da dieh vu. Bii viet phin tich 2 loai dich vu dich vu, ky thuat luu lupng vi tinh sin sing cita<br /> VPN tren nen MPLS: Mang heng ao giao thirc cong mang ATM vol kha nang ma rdng, tinh da diem eiia<br /> dudng bien Chuyen mach nhan da 0ao thiic BGP mang IP.<br /> MPLS VPN - VPN Idp 3 vi Dieh vu LAN heng io VPLS Ciu trite ciia mang MPLS gom cac bd dinh tuyin<br /> - VPN Idp 2, so sanh eie uu nhugc diem tren quan bien (router PE) giao tiip vdi thiit bi tai mang khach<br /> diem nhi eung cap dieh vu vi khach hang. hang (CE) vi cae bd dinh rayin trang tam (Router<br /> P) chuyen tiip eic gdi tin MPLS trong mang. PE cd<br /> 1. CONG NGHE MPLS VA DICH VU VPN 2 giao dien: giao dien giao tiip vdi mang MPLS vi<br /> MPLS giao dien 0ao tiip vdi mang IP. PE su dung bing<br /> chuyen tiip nhan lua chpn dudng dan ehuyin mach<br /> Mang trayin til ddng vai trd vd cimg quan trgng<br /> trong md hinh mang eiia mdi nha cung cip dich vu - nhan (LSP) din cie router P vi dinh rayin cie gdi<br /> ISP. Vdi nhu ciu gla tang nhanh bing thdng dudng tin IP tren ca sd thdng tin thiit bi CE. Viec phin phdi<br /> true, mang trayin til dugc thiit ki theo hudng day vi trao doi nhan su dung giao thirc phan phdi nhan<br /> phan phire tap nhu dinh rayin ve lop bien, phin (LDP). Cie giao thitc dinh rayin trong mang IP dugc<br /> mang loi chi xit ly don giin nhu chuyen mach de bo sung ky thuat luu lugng trong mang MPLS nhu<br /> ting khi ning dip img cua mang 161. Cdng nghe RSVP-TE, OSPF-TE, ISIS-TE.<br /> MPLS dugc thiit ki cho md hinh niy vol uu diem Mot trong eie dich vu dugc phit triin tren nin<br /> hon so vdi dinh rayen gdi tin thuin tiiy - ehuyin mang MPLS li dich vu VPN. Tren khia carih nha<br /> tiep nhan thay vi dpe gdi tm IP vi lira chgn dudng cung cap dich vu, dich vu VPN - mang rieng io<br /> dinh tiiyen trade khi ehuyin tiep goi tin. MPLS la eung cap dich vu kit ndi nhiiu mang khich hang<br /> kit hgp ciia kiiu chuyin mach ATM Idp 2 tien mang qua mang chia si chung. Dich vu VPN su dung kit<br /> <br /> <br /> <br /> TAP CHI CNTT&TT KY 1 (12.2009) 37<br />  CONG NGHE V I E N THONG<br /> <br /> Service Provider<br /> MPLS Backbone<br /> PE CE Tren n i n MPLS, dich vu VPN dugc phit triin<br /> thanh 2 kiiu: VPN Idp 3 v i VPN lop 2. Diim khac<br /> biet chinh eua 2 dich vu nay l i VPN lap 3 thuc hien<br /> cdng viee dinh rayin phite tap cho mang cita khich<br /> hing, cdn trong VPN Idp 2, khich hang phii tir ciu<br /> hinh, quan ly dinh tuyin giiia eic site trong mang<br /> cita minh. BGP MPLS VPN v i VPLS li 2 cdng nghe<br /> dai dien cho VPN lop 3 v i Idp 2 tren n i n MPLS.<br /> Hinh 1. Mo hinh mang MPLS<br /> <br /> <br /> - PE 2. D I C H V U BGP MPLS V P N<br /> <br /> BGP MPLS VPN cho phep cae site cita khach hing<br /> kit ndi qua mang true IP nhu sit dung mang rieng.<br /> BGP MPLS VPN dugc dinh nghia trong chuan IETF<br /> RFC 2547bis. BGP MPLS VPN sit dung MPLS chuyen<br /> tiip gdi tin qua mang trac v i BGP phin phdi dinh<br /> rayin qua mang true. Mdi BGP MPLS VPN l i mdt<br /> mang IP rieng vol eie dia chi IP cau hinh theo mang<br /> Hinh 2. Mo hinh mang VPN khich h i n g tai eie CE v i PE.<br /> Prjvoto Rout«s P« ering botween<br /> Customer A CE and PE Mdi router PE quin ly mot Co eg thdng tin ehuyin<br /> S«rvlco Provider<br /> MPLS Backbono<br /> tiep rieng ciia timg VPN, gpi l i bing Chuyen tiip<br /> PE<br /> PE<br /> '- « dinh rayen io - VRF. Bing VRF chira eic thdng tin<br /> paJ<br /> CEV'*'^"^<br /> dinh tuyin nhan tir thiit hi CE. Router PE sit dung<br /> E3 k '<br /> \ CE BGP lim bio hieu va cie giao thire dinh tuyin d i<br /> l^apE phan phdi hudng di gdi tin d i n cie thiit bi CE. Thiet<br /> Private Rout«s bl CE tro thinh ngang h i n g vdi router PE. Router<br /> Custo tnor B E^CE<br /> PE luu trii cie bing VRF ciing vdi bing dinh rayin<br /> Intemet cua n h i cung cap dich vu.<br /> Hinh 3. Mo hinh BGP MPLS VPN<br /> Vai trd chuyen tiip MPLS l i quan trong bdi router<br /> ndi io d i dim bio tinh rieng ra dir Ueu khich hang<br /> P trong mang ldi khdng can biit vi thdng tin dinh<br /> khi trayin qua mang dimg chung.<br /> tuyin rieng dau khich hing. Router PE sit dung 2<br /> Trong ha tang mang trayin til MPLS, eie site cua mio dau MPLS d i giao tiip tiidng tin dinh rayin.<br /> khich hang A cd thi kit ndi bao mat qua mang n h i Router PE vao tiiem mio diu Next-Hop BGP v i mio<br /> cung cip dich vu ma khdng bi can thiep bdi mang dau Next-Hop IGP (Interior Gateway Protocol) vao<br /> cita khach h i n g B. Luu lupng mang A chay qua eic<br /> gdi tin. Tai router PE ra, gdi tin dugc loai bo phan<br /> dudng ham kit ndi rieng dugc tao ra trong mang<br /> mio diu MPLS v i p h i n phdi tiip theo gdi tin IP d i n<br /> MPLS kit noi eie site cua A. Cie kit ndi nay nhin<br /> Router CE.<br /> tii phia khach hing gidng nhu dich vu kenh rieng,<br /> U'u nhu'dc diem ciia BGP MPLS VPN<br /> hoac qua mdt dudng io bio mat tien ciing mdt kit<br /> BGP MPLS VPN ed mdt sd uu diem khi lua chgn<br /> ndi vat ly.<br /> <br /> <br /> <br /> 38 TAP CHI CNTT&TT KY 1 ( 1 2 . 2 0 0 9 )<br />  CONG NGHE V I E N THONG<br /> <br /> <br /> cho dich vu VPN: bang duih rayin, thuc hien nhiiu ehuc ning nen<br /> - Tinh kit noi WAN - Cdng nghe niy su diing cho router PE phii ed eau hinh cao, thim chi dit hon<br /> kit ndi nhiiu dia diim each biet vi vat ly, duge trien Router ldi.<br /> khai nhu dieh vu thay thi hoac kit hgp vdi dich vu - Mang phire tap - Sd lugng dinh rayin ddng<br /> VPN trayin thdng. nhiiu lim gia ting tii, lam giim kha ning xit ly cita<br /> - Tinh dgng vi mim deo - Nhiing thay ddi ttong PE. Neu sd lugng khich hang ci nhin tang thi mang<br /> sa do kit ndi cd the thuc hien tren VPN mi khdng can md rdng, bo sung eic router PE.<br /> can cau hinh thu cdng tren thiet hi mang phia khich - Tinh on dinh vi toan ven mang - BGP MPLS VPN<br /> hang. ed thi lim inh hudng din tinh on duih vi toan ven<br /> - Tinh tirong thich - BGP MPLS VPN cd tiie duge cita mang. Niu thiit hi CE tai mdt khich hing boat<br /> triin khai tren cie dich vu tray nhap trayin thdng ddng khdng on dinh vi tic dpng din router PE, thi<br /> nhu Frame relay, dudng rieng, ATM. Ben canh dd, cae kenh dieh vu VPN eua khich hing khac cd thi<br /> cie dieh vu hien tai di ding ning cap len mang hi anh hudng.<br /> VPN mi khdng phii thay doi vi mat ciu tnic. - Quin ly mang phite tap - Cau hinh vi quan ly<br /> - Tich hgp di dang - VPN cd thi dugc tich hgp di dieh vu phire tap, mdi khich hing ed mdt hd sa<br /> ding cie dich vu IP khic nhu tray nhap Intemet, rieng tren router PE. Can phii quin ly bing dinh<br /> web, IPSec VPN. tuyin rieng tren PE ddi vol moi khich hing. Quin<br /> ly cau hinh CE la router ciing phire tap hon so vol<br /> - Tinh mg rdng vi dp tin cay - BGP MPLS VPN ma<br /> thiit bi Switch.<br /> rdng di ding, kha nang ma rdng tdi da chi gidi han<br /> bdi BGP vi dat dp tin cay eao dua tren BGP. - Them ciu hinh phia khich hing - Khich hing<br /> phii cau binh, quin ly them viec dinh rayin den<br /> Tuy nhien, BGP MPLS VPN ed mot sd gidi ban:<br /> PE thay vl dinh tuyin din eie router trong mang<br /> - Chi mang IP - Chimg chi diiu khiin luu lugng<br /> eiiahg.<br /> IP, khdng diiu khien luu lupng tren mang khic nhu<br /> SNA hay IPX neu ehiing khdng duge ddng gdi tiong Trong khi mot vii cac han chi tren cd thi giii<br /> gdi tin IP. Mac dii phan Idn khach hing dang chuyen quyit nhu ning cap phin cimg, phin mim cita<br /> qua ca sd ha tang IP duy nhit, ray nhien van eon router PE de bo sung eic tinh ning va ning lire xu<br /> rihiiu img dung chay tren cie mang khic. ly khic, thi mdt so han chi khic khdng di ding xu<br /> ly. Khdng thi triin khai dich vu vol khach hang cd<br /> - Chia se dinh tuyin - BGP MPLS VPN yeu ciu<br /> nhiiu giao thire trong mdi tradng LAM neu mang cita<br /> khich hang chia se thdng tin vi mien dinh rayin<br /> hg khdng phai mang toin IP. Viee chia si thdng tin<br /> tiong mang cita hg vol router PE. Diiu niy khdng<br /> dinh rayen rieng trong mang khich hang vdi router<br /> dugc nhiiu khich hing chap nhan vi tiit Id boat<br /> PE eua nhi cung cap dich vu khdng dugc nhiiu<br /> ddng ciing nhu cau tnic trong mang cita hp.<br /> ngudi chap nhin. Hp mudn cd mot kit noi dich vu<br /> - Router CE - De chia se thdng tin dinh rayin, trong sudt tir phia nha cung cip dich vu di tu quan<br /> thiit bi CE tai khich hing phii li mot router chir ly, diiu khien vi bio mit ttong mang npi bg.<br /> khdng duge la thiit bi don giin nhu Switch. Diiu<br /> Ddi vdi mot sd nhi cung cap dich vu cd mang<br /> niy raong img khich hing phii tdn tiiem ehl phi<br /> dudng true IP Idn va da triin khai router ldi, BGP<br /> tiang bi thiit bi cho mdi diim kit ndi.<br /> MPLS VPN la lua chpn tdt phat tilin khi hp di dang<br /> - Phu thudc eic router PE - Do yeu cau luu trii<br /> them, bdt va thay doi dich vu, sit dung khim pha<br /> <br /> <br /> <br /> TAP CHI CNTT&TT KY 1 (12.2009) 39<br />  CONG NGHE V I E N THONG<br /> <br /> <br /> No CE-PE routing Nguyen tic boat ddng co bin ciia dich vu VPLS<br /> sit dung giao tiiirc phan phdi nhan (LDP) di tiiinh<br /> lap mot mang diy dii eac dudng din chuyen mach<br /> nhan (LSP) - dudng ham giua tit ci cie nut PE. Cie<br /> dudng him dd dugc gin cie VPLS-ID nhin dang cie<br /> kit ndi io (VC LSP) gitra cie nut PE cho mang VPN.<br /> Cac VC LSP tao mdt ciu ndi logic cie PE ciu hinh<br /> VPLS cho khach hang.<br /> Hinh 4. Dich vu VPLS Tinh ning co bin ciia VPLS li khi nang tu hgc<br /> XIC UHt., 1 I.uB><br /> dia chi MAC giti tii phia mang khich hing eiia cac<br /> VIU lUCUb,, -^„ ^lU F.D<br /> ^nlllOT<br /> m Ett LK.) hnl IM Dtr R-n-<br /> router PE. Cie PE tiep nhin vi hpc dia chi MAC qua<br /> cac gdi tin unicast hoac multicast girl qua mang. Cie<br /> dia chi MAC sau khi tu hgc se dugc gin vdi mdt LSP<br /> la ea so eho viec chuyin tiip gdi tin trayin giiia cac<br /> nut PE.<br /> Viee quin ly sd lugng Idn dia chi MAC trong VPLS<br /> cd the thiie hien theo 2 giai phip. Cich thir nhat,<br /> phia khach hang sit dung cac thiit bi CPE la router,<br /> Hinh 5, Cache hoc dja chi MAC goi tin Broadcast khi dd cie PE nhin eic site phia khach hang nhu<br /> mot dia chi MAC duy nhit. Cich thir 2, khi cie CPE<br /> dinh tuyin tu ddng eua BGP, Tuy nhien vdi phin Idn<br /> li thiit hi Switch, eic PE phii ed khi ning gidi ban<br /> nhi eung cip dich vu Metro, gidi ban chinh eita BGP<br /> sd dia chi MAC cd thi hpc tit mdi kit ndi din.<br /> MPLS VPN li chi phi vi dp phire tap trong viec quan<br /> ly vi tich hgp vdi he thdng diiu hinh (OSS). Cac u'u nhu'dc diem ciia VPLS<br /> <br /> VPLS cd uu diem quan ttpng trong viec lua chgn<br /> 3. DICH v y VPLS dich vu Ethemet VPN<br /> Giai phap lop 2 MPLS mdi nhat cung cap dich vu - Kit ndi dd thi - Ky thuat niy li y radng cho kit<br /> da diem li dieh vu LAN rieng io - VPLS (Virraal ndi nhiiu diim trong mot khu vuc dd thi vi cd thi<br /> Private LAN Service). Vdi VPLS, nhiiu mang khach trien khai thay thi hoac md rpng dich vu kit ndi<br /> hing cd the giao tiip nhu kiiu kit ndi qua phan LAN-LAN trayin tiling.<br /> doan mang LAN Ethemet rieng. VPLS nim tren - Chi phi bleu qui - VPLS cho phep nha cung cip<br /> trayin tii MPLS vi viy thiit bi 161 li tuong tu BGP dich vu dugc Igi tir chi phi thip eua thiit bi Etiiemet,<br /> MPLS. Diim khic nhau chinh li glac tiip giiia thiit don giin vi phd biin mi khdng phii thuc hien md<br /> bi CE vi PE. Trong VPLS, CE khdng can li mot router rdng, dam bio dp tin eiy, ky thuat luu lugng vi cam<br /> vi PE khdng ngang hang vdi thiit bi CE nen PE kit SLA.<br /> khdng ein quin ly rieng biet bing dinh rayin ciia - Don 0 i n hda tien router PE - Vdi VPLS, cie PE<br /> mil CE. VPLS don giin chi anh xa luu lugng lop 2 khdng phai quin ly nhiiu bing dinh tuyin rieng<br /> din cua khich hang vio mdt LSP thich hgp trong cita khach hang.<br /> MPLS. VPLS boat ddng theo md hinh bao phu trong - Da giao tiiire - Ngoii luu lugng IP, VPLS ed the<br /> khi BGP MPLS VPN li mo hinh ngang hing. hd tig cac luu lugng khic nhu SNA, IPX.<br /> <br /> <br /> 40 I TAP CHI CNTT&TT KY 1 f 12.2009')<br />  CONG NGHE V I E N THONG<br /> <br /> <br /> - Vimg dinh tuyin rieng - VPLS khdng yeu ciu HieruihicalVPLS<br /> khich hing chia se thdng tin dinh rayin mang npi<br /> bd vdi PE<br /> - Thiit bi CE don giin - Khi thdng tm dinh rayen<br /> khich hang khdng can chia se, eic CE cd the li<br /> thiit bi don gian nhu Ethemet switch, bridge hoac<br /> Hinh 6. Mo hinh phan cap VPLS dang Hub-and-Spoke.<br /> Hub.<br /> - Sir phan ranh gidi - VPLS eung cap mdt ranh<br /> gidi rd ring giiia mang rieng khich hing va mang<br /> nhi ciing cip dich vu.<br /> - Bao hieu ddng - VPLS su dung MPLS di xac dinh<br /> bio bleu dgng eie dudng din mdi, cho phep luu<br /> lugng nhanh chdng ehuyin qua dudng du phdng<br /> hpic dudng tinh toin trade.<br /> - Tray nhap dich vu BGP MPLS VPN - Chimg cd the<br /> dugc sit dung di mang luu lugng tir mang Metro qua Hinh 7. Tich hpp VPLS vol mang hien co<br /> mang dudng true trong tray cap BGP MPLS VPN.<br /> trao ddi thdng tin vdi cie vimg Spoke.<br /> - Di ding quan ly - VPLS li don gian va chi phi<br /> Tich hdp VPLS vdi mang hien co<br /> thap vi mat quan ly<br /> - Tich hgp Metro Ethernet - VPLS cd the tich hgp VPLS ed thi khdng chi su dung trong dich vu<br /> vol dieh vu Metro Ethemet khic nhu Intemet, Web, Metro Net mi cd the tich hgp vdi mang ldi IP VPN<br /> dich vu du phdng vi khdi phuc. chay tren eie cdng nghe ldi khic nhu mang SDH thi<br /> he mdi, DWDM, RPR.<br /> - Tich hgp quan ly - Chimg tich hgp di ding vdi<br /> dieh vu Idp 2 nhu Frame relay vi ATM vdi cie thinh Cac ISP cd thi tiip tuc phit triin eie dich vu<br /> phan cung cip ha ting khic trong raong lai. trayin thdng nhu kenh rieng. Frame relay trong khi<br /> gidi thieu dich vu mdi li img dung cita mang Metro<br /> Dieh vu Ethemet VPN tren VPLS ciing tdn tai mot<br /> nhu VPLS, vi vay trinh phii loai bd loi nhuan hien<br /> sd diim ban chi:<br /> cd.<br /> - Khim phi tu ddng (Auto discovery) - VPLS<br /> Cie ISP gidi thieu dich vu bing rpng mdi tren<br /> khdng hd trg khim phi tu ddng cita PE tren ca sd<br /> cdng nghe DSL, cip vi WLAN ddi vdi khach hing<br /> LDP. VPLS sit dung LDP de xic dinh cich thinh lap<br /> nhd hoac thi tradng SME. Tuy nhien, su canh tranh<br /> mach diem da diim Ethemet.<br /> vi chat lugng, gii thinh lim dich vu bang rdng<br /> - Khi nang md rdng - Khi ma rdng mang VPLS, trayin thdng chay tren ATM vi SDH khdng gia tang<br /> sd lugng cie LSP full mesh, eic LDP ngang cap vi them dugc. Sit dung Metto Ethemet vdi VPLS eho<br /> viec phin phdi cie gdi tin sao chep gia tang, din phep cie nhi cung cip dich vu kit hgp dich vu<br /> den viec quin ly phiic tap, tieu ton til nguyen mang<br /> bang rpng hieu qua hon, vuon gin tdi khich hing<br /> ciing nhu khi nang bi tin cdng flooding dia chi<br /> hon mi khdng tdn them chi phi.<br /> MAC. Vin de niy ed the giai quyit bdi sit dung md<br /> hinh VPLS phan cap theo kiiu Hud - and - Spoke. Mae dii dudng kenh rieng. Frame relay tiip tuc<br /> Trong dd, cie VPLS PE ddng vai tid nhu cae Hub, gdp phan dap img nhu cau chia se dii Ueu, it cie<br /> <br /> <br /> <br /> TAP CHI CNTT&TT KY 1 ( 1 2 . 2 0 0 9 ) 41<br />  CONG NGHE V I E N THONG<br /> <br /> <br /> BGP MPLS VPN Uneh hpp vdi mdi tradng mang<br /> dudng mic, kit ndi nhiiu khu vuc qua mang WAN.<br /> Khi ning ma rdng vi viec su dung BGP, MPLS li giii<br /> phip tot md rpng cie mang VPN tren mang dudng<br /> true IP/MPLS trayin tiidng. BGP MPLS VPN sit dung<br /> kit ndi cie site VPN cita mang Metro niy sang site<br /> VPN cua mang Metro khic.<br /> Md hinh kit hgp VPLS vi BGP MPLS VPN se tan<br /> dung cac uu diim ciia mil cdng nghe. VPLS duge<br /> triin khai tai cie mang Metro, giim thieu yeu eau<br /> Hinh 8. Mo hinh ket hpp djch vu VPLS va BGP MPLS VPN<br /> xit ly tren router Metro, trien khai don gian, chi phi<br /> quin ly thap. BGP MPLS VPN phit trien tren mang<br /> ISP hoic khach hing cd the bio ve ngudn von bo true IP kit ndi mang VPN giiia cie Metro, tang do tin<br /> sung eho cie dich vu don giin dd dam bio hieu qui cay kit ndi Uen mang dua tren BGP.<br /> vi tiit kiem chi phi ban so vdi Ethemet, IP, MPLS.<br /> Hinh 8 li vi du dich vu MPLS lap 3 tren mang true<br /> Trong tuong lai, cac ISP cd thi xiy dung nhiiu hon<br /> cd thi kit hpp vol dich vu MPLS lop 2 tren mang<br /> mang trayen tai hieu qua chi phi va md rpng dich<br /> Metro di cung cip dieh vu VPLS trong mang Metro<br /> vu hien ed din khich hing mdi ma khdng ein cie<br /> vi dieh vu IP VPN giiia cac mang Metro. Lpi ich cita<br /> ISP hay khach hang diu ra them chi phi so vdi dieh<br /> cac nha cung cap dich vu gia tang khi su dung kit<br /> vu trayin thdng.<br /> hgp hai md hinh niy mi khdng lim tang dp phire<br /> tap cua mang loi, tan dung duge nhiing uu diim<br /> 4 . KET H O P D I C H V U VPLS VA BGP tren mang Metro. Ve phia khich hing, hg ciing cd<br /> MPLS V P N them cie lira chgn dich vu phii hgp vdi md hinh<br /> Tren day da phan tich chi tiit nhiing diem manh kinh doanh ciia minh.<br /> eiia hai cdng nghe VPN. Mdi nha cung cap dich vu se<br /> lira chpn giai phap phii hgp vdi yeu ciu eiia khich<br /> Tai lieu t h a m l