Bao Cao Mpls - Nhóm 2 - d10vta1

8/12/2019 Bao Cao Mpls - Nhm 2 - d10vta1

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HC VIN CNG NGHBU CHNH VIN THNG

C STHNH PHHCH MNH

KHOA VIN THNG II

-------------------------

Bo co ti:

TM HIU VMPLS TRAFFIC ENGINEERING

Gio vin hng dn : ThS Nguyn Xun Khnh

Lp : D10CQVT01-N

Nhm sinh vin thc hin :

L Quang Tm Nguyn Tin Hng

Nguyn Vn Ninh ng Hoi Khang Nguyn Thnh Hoi Ng Nguyn Huy Cng Hunh Tin Ngha Nguyn Trng Sang Nguyn c Huy


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L thuyt vMPLS Trafic Engineering Trang 1

CHNG I TNG QUAN VMPLS TE ...................................................................................................................... 3

CHNG II PHN PHI THNG TIN TRONG KTHUT LU LNG ........................................................ 82.1.1. Cu trc ca LSA ................................................................................................................................................................... 9

2.1.2. M t sub-TLV .................................................................................................................................................................... 10

2.2. Mrng giao thc IS-IS cho TE ........................................................................................................................................... 10

2.2.1. Cc mrng IS Reachability TLV (TLV 22) .......................................................................................................................... 11

2.2.2. Mrng IP Reachebility TLV (TLV 135) .............................................................................................................................. 11

2.2.3. Mrng Router ID TLV trong k thut lu lng (TLV 134) ............................................................................................... 12

2.3. Thtc lan truyn thng tin trong IGP ................................................................................................................................ 12

CHNG III C CHTHIT LP V TNH TON NG I TRONG MPLS TE...................................... 15

3.1. ............................................................................................................................................................. 15

3.2. C cthit lp ................................................................................................................................................... 15

3.2.1. o th -TE ............................................................................................................................................................. 15

CHNG IVCHUYN TIP LU LNG VO MPLS TE TUNNEL ................................................................ 28

4.1. Sac ru (nh tuy ).......................................................................................................................................... 28

4.2. Policy-based ru (nh tuyn theo chnh sch) ............................................................................................................. 28

4.3. Aurue Auce (nh tuyn tng bng cch thng bo) ....................................................................................... 28

4.4. Forwarding adjacency (Ln cn chuyn tip). ...................................................................................................................... 28

4.5. Drec mapp f AM raffic E uels (Gp rc tip lu lng ca AtoM trn cc TE Tunnel):....................... 29

4.6. Class-based tunnel selection (la chn cc Class-based Tunnel) ......................................................................................... 29

CHNG V TI NH TUYN NHANH .................................................................................................................. 30

5.1. Fast ReRoute nh tuyn nhanh.................................................................................................................................. 30

5.2. FRR- Bo vlin kt (Link Protection) ................................................................................................................................. 30

5.3. FRRBo V Node (Node Protection) ................................................................................................................................ 34

BI M PHNG TRN GNS3 ....................................................................................................................................... 36

Cc n du lm c : ............................................................................................................................................................. 36


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To tunnel; xem xt trng thi cc bn RIB, FIB, LIB, LFIB khi thay i cc thuc tnh: banwidth, attribute-flag; Load-balancing; FRR

Link Protect .......................................................................................................................................................................................... 36


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Chng I TNG QUAN VMPLS TE1.1. Gii thiu vMPLS TE:

Kthut lu lng hay l kthut iu khin lu lng qua mng c trin khai 1 thi gian nhngn chyu chhot ng trn mng ATM hoc Frame Relay. Vai tr ca TE l iu khin lu lng t1 edgerouter ny n 1 edge router khc trong mng theo cch ti u nht. Trong cc mng ny, cc mch o c

thit lp a lu lng t1 edge router ny n 1 edge router trn chuyn mch ATM hoc Frame Relay.Ngy nay, r rng rng IP ang l giao thc mng c sdng phbin. Mc d trc y mng IP hot ngda trn nn tng Frame Relay hoc ATM nhng cng ngy cng c nhiu mng hot ng trn mng thun IPhay IP chy trn 1 mng dng MPLS. Do gii php TE cn thit cho mng IP. Mc d TE vn c thchachy trn 1 mng thun IP c nhng l c thtrn 1 mng IP/MPLS vi gii php TE.

nh tuyn trong mng IP c iu chnh bi nhu cu c c lu lng truy cp trn mng lnnht c th. l l do ti sao nh tuyn IP c da trn nguyn tc nh tuyn chi ph c bn thp nht. Ttccc nh tuyn vi giao thc IP c chi ph lin quan n cc lin kt trong mng. Stch ly ca cc chi phtt ccc lin kt ca mt ng i c sdng tnh ton ng i chi ph nhnht chuyn tip lu

lng truy cp thng qua mng. Chi ph l mt metric duy nht c gn cho mt lin kt (V d: OpenShortest Path First [OSPF] v Intermediate System-to-Intermediate System [IS-IS]), mt metric tng hp. (Vd: giao thc Gateway Routing Protocol [IGRP] v Enhanced Interior Gateway Routing Protocol [EIGRP]),hoc n gin l chshop (V d: Routing Information Protocol [RIP] v RIPv2).

M hnh chuyn tip IP da trn chi ph thp nht ny chuyn tip data vo cc tuyn. Hn na, ccgi IP c chuyn tip trn mi hop (router) da trn a chIP ch v c lp vi cc gi tin IP cchuyn tip trn router trc khi hoc sau khi ra khi hop ny.Ngoi ra, cc m hnh chuyn tip IP khng xemxt bng thng hin c sn ca lin kt, trong c thkhc nhau ng kso vi chi ph c gn cho cc linkt. do , mt router c thtip tc chuyn tip lu lng IP vo mt lin kt, mc d lin kt bmt gi

dliu do thiu bng thng chuyn tip tt ccc lung dliu m bng nh tuyn chra.

Kt quca vic skin ny trong chuyn tip cc gi tin IP l mt slin kt c thl nghn trongmng, trong khi cc lin kt khc c th khng c sdng ng mc. Tt nhin, ta c thch n tllulng truy cp trn cc lin kt ca mng v lp khoch nng cp hthng thch ng vi lu lng. Thmbng thng cho cc lin kt l khng dthc hin, n cn lp khoch v cn c thi gian. Bi v lu lng

gia cc node c ththay i hon ton bt ngv khng phi l lun lun cnh, TE c thmang li c giiphp bng cch iu khin lu lng hoc mt phn ca n i tcc lin kt qu ti.


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M hnh mng chuyn tip IP

Nu tt ccc lin kt trong mng mu ny c cng chi ph, con ng chi ph thp nht trouter R1n router R5 l con ng R1-R2-R5. R rng, tt clu lng truy cp tR1 n R5 ssdng ng dnR1-R2-R5 v ng R1-R3-R4-R5 skhng c lu lng truy cp. Trong c mng thc s, mi thkhng phir rng. nhiu lung lu lng c thtn ti v lung trn cc lin kt c thkhc nhau rt nhiu. Ta c thphn phi ti trng ng u hn bng tnh ton vi chi ph ca cc lin kt cho ring giao thc nh tuyn.iu c thphn phi lu lng ng u hn, nhng ta khng thc thphn phi lu lng,hon ho, biv trong cc mng thc s, lin kt hu nh khng bao gisdng cng mt bng thng. Trong mng Hnh 1.1,

ta c thm bo rng hai ng nh nhau bng cch m bo rngtng cc chi ph ca cc lin kt trongng dn R1-R2-R5 v ng dn R1-R3-R4-R5 u bnh ng. kt qusl cn bng ti lu lng gia R1v R5 trn hai con ng. iu ny stt hn cho cc lu lng truy cp gia R1 v R5, nhng chc chn sclu lng truy cp vo mng trn R2 hoc R4 v nh vy. y l cng l mt vn , bi v c hai tuyn tR2

n R4, mt ch hai tuyn, hoc l ba. Ta c thc cng mt vn gia cc router R3 v R5hoc bt knhng router khc. Ni cch khc, vn ti cc lin kt bnh ng vi lu lng truy cp l mt vn kh

khn bi nu ta chcn cgng iu chnh chi ph ca mi lin kt trong mng.

tng thm sphc tp ca vn , tc ca bt klin kt c thc nng cp, cho php bngthng ln hn trn cc lin kt nht nh. Vo thi im , ta cn phi thit lp li tu v thay i chi phca cc lin kt mt cch thcng trn ton mng. iu ny r rng l khng khthi tmt quan im hot

ng.V th, MPLS TE l mt gii php cho vn ny trong cc cch sau:

MPLS TE cung cp hiu qutruyn ca lu lng truy cp trn ton mng, trnh nghn mng v sdng hp l lin kt.

MPLS TE xt n (tnh) bng thng cu hnh cc lin kt. MPLS TE c cc thuc tnh lin kt vo ng truyn (v d, tr, jitter). MPLS TE iu chnh tng thay i bng thng vcc thuc tnh lin kt. Ngun nh tuyn c bn cho php xy dng traffic-engineered tri ngc vi nh tuyn IP.


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MPLS TE cho php mt s TE tngun ti ch ca router l mt mt ng i chuyn mch nhn(LSP) c thtnh ton cc tuyn ng hiu qunht qua mng vpha ch LSP qua router.Cc router bin cthlm iu nu n c cu trc lin kt ca mng. Hn na router bin, cn bit bng thng cn li trn ttccc lin kt ca mng. Cui cng, ta cn phi kch hot MPLS trn cc router ta c ththit lp LSP tu n cui. Thc tl chuyn mch nhn l sdng v cho php chuyn tip IP cho cc ngun da trn nhtuyn thay v chda trn nh tuyn a chIP ch. l bi v MPLS khng chuyn tip trong mt phng dliu, bng cch kt hp mt nhn n trong cc c sthng tin chuyn tip nhn (LFIB) v trao i n vi mt

nhn i.V vy, router bin cp nhn nh tuyn chuyn mch (LSR) ca LSP c thxc nh nh tuyn cagi c nhn, sau khi tt cLSRs ng cc nhn sdng m LSP. Hnh 1.2 cho thy mtv dvm ngun

da trn khnng ca MPLS TE nh tuyn.

MPLS TE head v end router

minh ha cho khi nim ny, router R6 v R7 c thm vo pha trc ca router R1. Gisrouter R6 v R7 mun gi lu lng truy cp n R5. Nu mng ny chang chy chuyn tip IP th lu lngi theo con ng chR1-R2-R5 v IP c thc hin mt cch c lp trn mi hop trong mng. V vy, routerR1 khng c thng tin R6 v R7, v n chuyn tip lu lng theo quyt nh chuyn tip ca ring mnh datrn bng nh tuyn IP. R6 v R7 c thc chnh sch khc nhau, mc d. R6 c thmun gi lu lng dctheo con ng R6-R1-R2-R5, trong khi R7 c thmun chuyn tip lu lng dc theo con ng R7-R1-R3-R4-R5, l khng tht c trong c mng IP n gin. Nu mng ang chy MPLS, ta c ththit lp haing ny nhhai LSPs khc nhau nhn hiu khc nhau c sdng. Ti router R1, nhn n khc nhau

gi trchra cho d cc gi thuc vLSP vi R6 nh cc u cui hoc cc LSP vi R7. R1 sau chuyn tipcc gi tin trn mt trong hai LSPs, nhng n khng chuyn tip gi theo ring ca mnh nh trng hp vi

chuyn tip IP n gin.

Ta c thtrin khai MPLS TE trong bt kmng c LSRs. Tuy nhin, bi v bng thng v cc thuctnh khc ca lin kt c bit n LSR ca LSPs, nh tuyn giao thc c sdng gia MPLS TE thit bu cui phi l mt trng thi lin kt vi giao thc nh tuyn. Vi giao thc nh tuyn c trng thi linkt, mi router xy dng mt trng thi ca cc lin kt ring ca mnh,m sau qung b cho tt ccc routerkhc trong cng khu vc. iu ny c ngha rng tt ccc bnh tuyn trong khu vc c tt ccc thng tin


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cu trc lin kt ca khu vc . Cui u LSR do c thtm ra cch t cc MPLS LSP lu lng. iuny cho php nh tuyn da trn ngun. LSP ny c gi l mt MPLS TE Tunnel. N khng ging nh mtTunnel GRE, tuy nhin. Mt Tunnel TE l theo mt hng, v mtLSP l theo mt hng, v n c cu hnhTunnel TE chtrn vo u cui LSR v khng da trn cui ui LSR ca LSP. Hn na, mt Tunnel TE phi

c bo hiu, trong khi mt Tunnel GRE khng c c.

Nu TE c kch hot trong mng, ta c thsdng n theo hai cch khc nhau. u tin, ta c thto

MPLS Tunnel TE gia mi cp LSRs cnh trong mng ca ta. Nh vy, ta c thiu khin tt ccc lulng trong mng, trnh tc nghn trong n, v cung cp cho tt ccc lu lng cc c im (bng thng, tr, jitter,v.v) cn thit. Mt v dl MPLS VPN, ni ta c thto ra mt Tunnel TE ttt ccc router PE tt ccc router PE khc. Thhai, ta c thkch hot MPLS TE khp mi ni trong mng nhng khng cTunnel TE cho n khi hl cn thit. Ta c thto ra cc Tunnel TE theo yu cu. Mt v din hnh cavic ny l khi ta to ra cc Tunnel TE iu tit lu lng trn mt im nng hoc qu ti im trong mng.Quan trng la lm thno iu khin lu lng vi cc LSPs TE thng qua mng l lm thno lp bn

lu lng vo chng.

1.2. Tng quan hot ng ca MPLS TE1.2.1. Cc chc nng chnh ca MPLS TE:

Hn chlin kt (gi hn lu lng trn mi lin kt c thhtrv scc TE Tunnel c thsdng lin kt).

Phn phi thng tin TE (do TE-kch hot giao thc nh tuyn MPLS) Sdng thut ton tnh ton ng dn (PCALC) tnh ton ng i tt nht tngun ti ch

trn cc LSR.

Giao thc bo hiu RSVP c sdng bo hiu cc TE Tunnel trn mng. Thc hin chuyn tip lu lng vo cc TE Tunnel

MPLS TE Buiding Blocks


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Ci tn u tin c sdng ti Cisco cho MPLS TE l Routing with Resource Reservation, cn cgi l RRR hoc R3. L do chnh c MPLS TE l nh tuyn hoc iu khin lu lng theo cc ti nguynhoc rng buc. Cc ngun ti nguyn l bng thng ca lin kt v mt sthuc tnh ca cc lin kt m ccnh iu hnh chnh. nhng thuc tnh ny c cu hnh trn cc lin kt v qung b bi cc giao thc nh

tuyn link state IGP (OSPF hay IS-IS.)

Thay v to ra mt giao thc mi truyn thng tin ny v qung b n n tt ccc LSRs, OSPF v

IS-IS c mrng phi c thm thng tin ny. Khi ta cu hnh mt Tunnel TE trn mtLSR, n trthnh mt u cui LSR ca Tunnel TE hoc TE LSP. Sau ta chnh im n LSR Tunnel TE v cc rngbuc n phi tun theo.

mt ngha c la chn bi ngi qun l. V d, lin kt l mt lin kt pos vi mt tc ln hn 48 OC,

hoc lin kt l lin lc a, hoc mt lin kt m c mt schm trnhhn 100 ms.

Mt lin kt c thc nhiu ngun ti nguyn lin kt vi n, vi ti a l 32. cc ngun ti nguynang qung b trn khp cc khu vc bt ckhi no hthay i trong gi trhoc nh k. qung b nhng thayi ny IGP tng thch ngc. iu ny c ngha rng khng phi tt ccc bnh tuyn phi htr

nhngthay i trc khi ta c thchy MPLS TE. Bnh tuyn khng hiu nhng thay i IGP i vi TE chbqua chng.

1.2.2. Phn phi thng tin trong MPLS TE:Cc router LSR trong min chuyn mch MPLS c trin khai kthut lu lng cn bit c thng tin

topo mng cng nh thuc tnh ca tt ccc lin kt trong mng xy dng mt c sdliu cho vic tnhton ra nhng tuyn LSP khthi. c c nhng thng tin ny th trong mng phi sdng cc giao thcnh tuyn link-state (nh IS-IS hay OSPF). Nhng giao thc nh tuyn link-state ny c khnng gi thngtin ca tt ccc lin kt ca mt router n cc router khc trong mt vng, nh vy mi router trong vng c

thtnh ton c nhng tuyn i khthi . Giao thc nh tuyn vector khng thc sdng y bi v nchgi thng tin vtuyn ng m n cho l tt nht, m bqua nhng tuyn khthi khc.

Cc giao thc nh tuyn dng Link-State (OSPF v IS-IS) c mrng cho MPLS-TE khng chqungb cc thng tin vlin kt thng thng m n cn mang thm thng tin rng buc ca cc lin kt trongmin MPLS nh l:

Traffic Engineering Metric: l mt tham smetric sdng cho MPLS TE, do ngi qun trt v mcnh TE metric bng vi IGP metric.

Maximum Bandwidth: Bng thng ti a c dng cho lin kt trn mt hng truyn. Tham snythng dng cu hnh bng thng cho lin kt

Maximum Reservable Bandwidth: Bng thng c thdnh ring ti a trn lin kt, thng gi trmcnh nn l gi trMaximum Bandwidth, n vl byte/s Unreserved Bandwidth: Phn bng thng khdng cn li cha c sdng trn lin kt. Administrative Group: Cn c gi l lp ti nguyn (mu) cha 4 octets ca bit mask c chnh

bi ngi qun trmng, mi bit c thit lp tng ng vi mt mu (lp ti nguyn) gn chointerface. Bit nhnht dnh cho group 0, ln nht dnh cho group 31


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Chng II PHN PHI THNG TIN TRONG K THUT LU LNG

Cc router LSR trong min chuyn mch MPLS c trin khai kthut lu lng cn bit c thng tintopo mng cng nh thuc tnh ca tt ccc lin kt trong mng xy dng mt c sdliu cho vic tnh

ton ra nhng tuyn LSP khthi. c c nhng thng tin ny th trong mng phi sdng cc giao thcnh tuyn link-state (nh IS-IS hay OSPF). Nhng giao thc nh tuyn link-state ny c khnng gi thngtin ca tt ccc lin kt ca mt router n cc router khc trong mt vng, nh vy mi router trong vng cthtnh ton c nhng tuyn i khthi. Giao thc nh tuyn vector khng thc sdng y bi v nchgi thng tin vtuyn ng m n cho l tt nht, m bqua nhng tuyn khthi khc.

Cc giao thc nh tuyn dng Link-State (OSPF v IS-IS) c mrng cho MPLS-TE khng chqungb cc thng tin vlin kt thng thng m n cn mang thm thng tin rng buc ca cc lin kt trongmin MPLS nh l:

Traffic Engineering Metric: l mt tham smetric sdng cho MPLS TE, do ngiqun trt v mcnh TE metric bng vi IGP metric.

Maximum Bandwidth: Bng thng ti a c dng cho lin kt trn mt hngtruyn. Tham snythng dng cu hnh bng thng cho lin kt.

Maximum Reservable Bandwidth: Bng thng c thdnh ring ti a trn lin kt,thng gi trmcnh nn l gi trMaximum Bandwidth, n vl byte/s

Unreserved Bandwidth: Phn bng thng khdng cn li cha c sdngtrn linkt. Administrative Group: Cnc gi l lp ti nguyn (mu) cha 4 octets ca bit maskc chnh

bi ngi qun trmng, mi bit c thit lp tng ng vi mt mu (lp ti nguyn) gn chointerface. Bit nhnht dnh cho group 0, ln nht dnh cho group 31.

2.1.Phn mrng ca OSPF cho TE

OSPF mrng cho TE mang thm thng tin thuc tnh ca lin kt c cu hnh trn mt router. Ccthng tin c cung cp bi cc phn mrng c thc sdng xy dng mt c sdliu trngthi lin kt mrng ging nh c sdliu trng thi lin kt

thng thng, skhc bit l c sdliu trng thi lin kt c mrng (cn c gi l c sdliu kthut lu lng) c thm cc thuc tnh lin kt. Ngi ta c thsdng c sdliu kthut lulng :

Gim st cc thuc tnh lin kt. nh tuyn ngun da vo cc rng buc.Phn mrng ny gm 3 dng bn tin Opaque LSA l loi 9, loi 10 v loi 11, chng khc nhau phmvi lan truyn:

Loi 9: khng lan truyn ra ngoi subnet ca n (link-local) Loi 10: qung b trong vng ca n ( trong cc router bin ) Loi 11: qung b gia cc OSPF domain vi nhau


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2.1.1. Cu trc ca LSALSA Header

Cu trc chung ca mt Opaque LSA:

LSA ID ca 1 opaque LSA c nh ngha gm c 8 bit m tkiu ddiu (Opaque type) v 24 bit mtdliu cth(Opaque ID). Trong kthut lu lng LSA c opaque type l 1. Cn li 24 bit ltrng i tng, l mt gi trty dng duy tr nhiu LSA TE. Gi trln nht ca LSAs TE la16777216.

Trong trng Option c thm mt bit mi l O-bit, bit ny chra mt router c khnng truyn vnhn cc Opaque LSA hay khng.

* O DC EA N/P MC E *

Trng Option

TLV Header

Gm Router Address TLV v Link TLV

Router Address TLV: Chra mt a chIP n nh ca router qung b m lun cthkt ni nu cbt k mt kt ni no ti n v thng dng mt a chloopback. Trong cc giao thc khc, RouterAddress c xem nh mt Router ID.

Link TLV: Link TLV m tmt lin kt n, c xc nh bi mt tp cc sub-TLV,cc sub-TLV nymi thc smang thng tin thuc tnh ca lin kt. Chc mt link TLV c mang trong mt LSA.


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2.1.2. M tsub-TLV

STT Tn Sub-TLV di (Octet)

1 Link Type 1

2 Link ID 4

3 Local Interface IP Address 4

4 Remote Interface IP Address 4

5 Traffic Engineering Metric 4

6 Maximum Bandwidth 4

7 Maximum Reservable Bandwidth 4

8 Unreserved Bandwidth 32

9 Administrative Group 4

Link Type: Chra lin kt ny l lin kt im-im hay lin kt im-a im Link ID: Xc nh u cui ca lin kt (router ID): vi lin kt im-im th lrouter ID ca

neighbor, vi lin kt a im th l a chinterface ca router c chnh.

Local Interface IP Address: a chinterface tng ng ca lin kt ti router. Remote Interface IP Address: a chIP ca interface neighbor tng ng trn lin kt Unreserved Bandwidth: Phn bng thng khdng cn li cha c sdng ti micp trong 8 cp

u tin

-Gi trng ca bng thng c thit lp theo 8 cp u tin tcao ti thp theo thtt0-7, TE-LSP c u tin cao hn c thchim gibng thng ca u tin thp hn nhng ngc li th

khng.-Gi trca n nhhn hoc bng gi trca Maximum Reservable Bandwidth , ban u c thit lp

bng gi trca Maximum Reservable Bandwidth.

2.2. Mrng giao thc IS-IS cho TEIS-IS c cc trng Type-lengh-value mi nh km trong cc thng ip PDU link-state ca n.Phn m

rng cho php IS-IS mang cc thng tin thuc tnh lin kt ca MPLS-TE.

C ba loi TLV mi:

1. u tin l mrng IS Reachability TLV hoc TLV type 22 .N l c xy dng tTLV type 2 (ISReachability TLV), m tnhng IS-IS neighbor ca n.

2. TLV mi thhai l mrng IP Reachability TLV (TLV type 135). N l sktha tTLV type 128 v130.

3. TLV 134 - Router ID TLV trong kthut lu lng.


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2.2.1. Cc mrng IS Reachability TLV (TLV 22)i vi IS Reachability TLV thng thng dnh 4 octet cho 3 metric {metric mc nh, delay, monetary

cost, reliability}. Metric mc nh thng c sdng nhng chc 1 octet, trong mt bit ch

metric ny l metric ni vng hay ngoi vng, mt bit dnh ring v 6 bit cn li cha gi trMetric thcs(0-63) v thcn phi mrng gi trmetric ny.

Nh vy mt TLV thng thng cn 11 octet (4 octet metric v 11 octet System ID) nhn din mtnode lng ging th, v mt IS Reachability TLV nh vy c thcha dliu m tca 23 lng ging.TLV 22 ny nu khng sdng cc sub-TLV m tthm vlin kt th n vn c thcha thng tin v23 lng ging. V di 3 octet ca metric mc nh phn bit y l thng tin tin nh tuyn ni vngso vi 4 octet metric ca TLV 135 l metric ca thng tin nh tuyn lin vng.

Bng m tSub TLV

STT Tn Sub di (octet)0-2 Unassigned -

3 Administrative group 4

4-5 Unassigned -

6 IPv4 interface address 4

7 Unassigned -

8 IPv4 neighbor address 4

9 Maximum Link Bandwidth 410 Reservable Link Bandwidth 4

11 Unreserved Bandwidth 32

12-17 Unassigned -

18 TE metric 3

19-254 Unassigned -

255 Reserved -

Vc bn, dliu sub-TLV ca IS-IS m tthuc tnh lin kt ging vi dliu sub-TLV ca OSPF.

2.2.2. Mrng IP Reachebility TLV (TLV 135)Mrng IP reachability l TLV 135. N gii quyt hai vn cn tn ti ca IP Reachability TLV l:

- Mt l, IP Reachability TLV c 4 metric, nhng chc metric mc nh c sdng thng xuyn


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nhng n bgii hn trong khong gi tr0-63.

- Hai l vn ti phn phi tuyn. Nu cc router phn phi li IP prefixes theo chai hng giamc 1 v 2 m khng cn bt k c chbxung, router skhng thxc nh vng lp ca nhtuyn thng tin. Khi mt router hc c mt prefix thng qua nh tuyn mc 2 v qung b prefix xung mc 1, router mc 1 cng c thgi ngc trli to nn vng lp. gii quyt vn ny TLV 135 cung cp 32 bit (4 octet) cho trng default metric, v thm 1 bit up/down cho bitrng mt Prefix c phn phi trong hphn cp.

Up/down bit

Mt mrng mi trong Reachability TLV l up/down bit, c thit lp l 0 khi mt prefix ln u tinc a vo IS-IS. Nu mt prefix c qung b tcp cao hn n mc thp hn th bit up/downc thit lp l 1, chra rng cc prefix c thi xung hphn cp.Tin tc bit up/down l 1 chcthqung b xung mc thp hn.

Nu mt prefix c qung b tvng ny sang vng khc cng cp, bit up/down cng c thit lpl 1 (tnh trng ny pht sinh khi mt router ng vai tr nh nhiu bnh tuyn o gia cng cp

nhng trong cc vng khc nhau.)Mrng IP reachability TLV vi cc sub-TLVs

Mt bit cho thy shin din ca Sub-TLV. Khi bit ny l 0 tc khng c Sub-TLV, nu bit ny l 1octet u tin sau tin tc hiu l chiu di ca sub-TLV lin kt vi tin tIPv4 ny

2.2.3. Mrng Router ID TLV trong k thut lu lng (TLV 134)Router ID TLV trong k thut lu lng l TLV 134.

TLV Router ID cha 4 octet ID ca router ngun trong LSP. iu ny htrtrong nh tuyn ddnghn:

-i vi kthut lu lng, n m bo rng n a ch lun lun c tham chiu n, khng phthuc vo trng thi ca giao din ca nt.

-Nu OSPF cng ang hot ng trong phm vi, kthut lu lng c thtnh ton nh xgia cutrc OSPF v IS-IS.

Nu mt router khng trin khai kthut lu lng, n c ththm hoc bqua TLV Router ID. Numt router thc hin kthut lu lng, n phi sdng TLV ny cho TE-LSP ca n.

Nu mt router n qung b prefix thng qua Border Gateway Protocol (BGP) th TE Routed ID nn lBGP router ID.

2.3. Thtc lan truyn thng tin trong IGPGiao thc nh tuyn ni vng (IGP) slan truyn thng tin vTE trong cc trng hp sau:

1) Thay i trng thi lin kt.2)Thay i cu hnh kt ni.3)Lan truyn theo chu k: c sdng vi chu klan truyn mc nh l 3 pht. v khi lin kt c sthay

i nhvbng thng dnh ring th n skhng lan truyn ngay sthay i ny ra ton mng.


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4)Sthay i ca bng thng dnh ring: Khi c sthay i th router skhng lan truyn ngay thng tinthay i ny ngay nu nh sthay i vbng thng cha vt ngng thit lp. C 2 ngngthay i l:

Ngng ln khi bng thng dnh ring tng ln mc nh l 15, 30, 45, 60, 75, 80, 85, 90,95, 97, 98, 99 v 100

Ngng xung l khi bng thng dnh ring gim: 100, 99, 98, 97, 96, 95, 80, 75, 60, 45, 30,15.

Khi thit lp tht bi mt ng hm: Headend-LSR cgng thit lp mt tuyn LSP m n tnhton bng bn tin RSVP. Tuy nhin vic thit lp c ththt bi nu c mt ng TE-LSP khc chimbng thng ca lin kt m tuyn TE ban u i qua v thkhng bng thng cn thit cho n, m sthay i bng thng ny khng c thng bo do cha vt ngng. v vy khi vic thit lp tht birouter trung gian slan truyn thng tin mi. Headend-LSR scp nht dliu v tnh ton mtng i khc.

2.4. nh tuyn v chi ph ca TE-LSP2.4.1. Thuc tnh lin kt trong MPLS TE

Mi lin kt trong mng MLS c trin khai kthut lu lng c nhng c tnh c lan truyn ra ccrouter, cc router ny khi tnh ton mt tuyn LSP xem xt liu c thsdng c mt lin kt no cho TE-LSP hay khng. Cc lin kt c nhng cu hnh c tnh nh sau:

Bng thng dnh ring ln nht (Maximum reservable bandwidth): l bng thngdnh ring ln nhttrong phn dng chung, phn m cc ng TE thng thng c thsdng.

Cthuc tnh (Affinity flag): chra lp ti nguyn, khnnghay chnh sch qun trca lin kt. Cthuc tnh Affinity gm 32 bit, mi bit c thc thit lp theo mc ch ca ngi qun tr. V dbt ny c thchlin kt ny c trnhhn 100ms, cn bit khc chlin kt c tc cao,

TE metric: hay cn gi l trng squn tr(Administrative Weight).MPLS TE sdng TE metricca lin kt nh tuyn TE-LSP v mc nh TE metric bng IGP metric. C ththay i TEmetric khc vi IGP metric c chnh sch chn ng tt hn. V d: IGP metric dng phnnh nhng tuyn ng i c bng thng ln ph hp vi lu lng dliu, cn TE metric phn nhnhng tuyn ng c trthp ph vi vi lu lng voice.

Nhm lin kt chia snguy c: chnh nhng lin kt c dng chung ng truynvt l (v dcpquang). Nu ng truyn ny bt th snhng lit kt ny bnh hng cng thi im. SRLGc sdng cho trng hp dphng FRR

Bng thng sub-pool dnh ring ln nht: l bng thng dnh ring cho nhng dch vphn bit(DiffServ-aware). N l mt phanh mnh ca bng thng dng chung.

2.4.2. Thuc tnh ca trung kMPLS TEo Bao gm:

a chch ca TE-LSP: l MPLS TE router ID ca tailend-LSR, im ch ca LSPnh tuyn ti. Bng thng mong mun: l bng thng yu cu ca TE-LSP Affinity bit: thuc tnh ny iu khin TE-LSP sdng cc lin kt, cho php p tcc chnh sch

chn ng bng vic bao gm hay loi trmt slin kt no . Thuc tnh Affinity c dng chuibit nh sau: Affinity (32bits), Mask (32 bits). Mask chnh cc bit no trong lp ti nguyn cn c


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kim tra. Lin kt c php sdng nu chui Affinity bit ca TE-LSP trng vi Affinity Flag ca linkt sau khi cng thc hin php AND vi Mask. Gi trmc nh ca Mask l 0x0000FFFF.

u tin thit lp v cm gi(Setup and hold Priority): lc chu tin cho mt sng hm lm victrc nhng ng hm khc. Mi ng hm c mt u tin, cc ng hm t quan trng hn by ra khi ng i v ti nguyn ca n nhng li cho ng hm quan trng hn. V d: Khi cmt TE-LSP khc n cnh tranh bng thng trn lin kt vi TE-LSP ban u th Setup Priority ca

TE-LSP mi c so snh vi Hold Priority ca TE-LSP c, nu c u tin cao hn (chsnhhn)th TE-LSP mi sc u tin thit lp v TE-LSP c phi nhng li ti nguyn.

Ti ti u ha (Reoptimization): c trng ca mng l bin ng theo thi gian, v dc thm cc tinguyn mi kch hot, nhng lin kt bscc phc hi, cc ti nguyn dnh ring trc thu hiv vy khi cc ti nguyn thay i trng thi th cc LSP thit lp trc khng cn l ti u nht nann lun duy tr trng thi ti u nht ca LSP th cn thc hin ti u ti ha li. C ththc hintheo ba c chsau:

1) Ti ti u theo chu k: chu kti ti u c ththay i t0 n 168 gi, mc nh l 1 gi. Chukbng 0 tc l khng sdng chc nng ny.

2) Ti ti u theo skin: khi mt lin kt c khc phc scv quay trli trng thi up.3) Ti ti u thcng: ti ti u li ngay khi c yu cu .Ty chn thit lp ng (Path setup

option): ta c ththit lp mt tuyn TE-LSP theohai cch l: tuyn tng minh v tuyn ng.


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Chng III C CHTHIT LP V TNH TON NG I TRONGMPLS TE

3.1. Tnh ton ng iPCALC l mt thut ton SPF m MPLS TE sdng. SPF l thut ton m OSPF v IS-IS dng tnh

ton tuyn ng ngn nht n im ch. SPF iu khin trn mi router v n dng database ly tOSPF

hoc IS-IS lc ra bng nh tuyn. Bi v OSPF v IS-IS c mrng vkhnng phn phi ti nguynnn PCAL c thtnh ton ng truyn khng chda vo ng i ngn nht m cn da vo ti nguyn can. Lc thut ton SPF trthnh thut ton CSPF. Vc bn, khi SPF c xy dng th nhng lin kt nokhng c bng thng hoc khng p ng c yu cu vti nguyn sbloi b. Kt quthu c cathut ton CSPF khng phi l mt bng nh tuyn m l mt tuyn ng. Tuyn ng ny l mt tuyntng minh gm mt dy cc a chIP, mi a chIP i din cho mt cng giao tip trn mt router. Tuyntng minh ny c dng thit lp TE LSP. PCALC xy dng duy nht mt tuyn ng, khng bao gic2 hoc nhiu hn. V vy, iu quan trng l phi chn c mt tuyn ng tt nht trong trng hp cctuyn ng u c thp ng c yu cu. Nu nhiu tuyn ng c cng chi ph (cost) v thomn iu

kin rng buc th schn tuyn ng c bng thng ti thiu ln nht. Nu cc tuyn ng u tt v cbng thng ti thiu ln nht u bng nhau, tuyn ng no c t shop nht sc chn. Nu 2 trng hptrn u thoth Cisco IOS schn ngu nhin mt tuyn ng.

3.2. C chthit lp ng iSau khi tm ng dn bng thut ton CSPF v v chng ta sdng kthut MPLS chuyn tip gi nnvic tip theo cn lm l xy dng LSP cng vi dnh sn ti nguyn mng trn ng dn .C hai giao thc

thc hin cng vic ny: giao thc RSVP mrng v giao thc CR-LDP.

3.2.1. Giao thc RSVP-TE3.2.1.1.Giao thc RSVP mrng:Vi giao thc RSVP, LSP c xy dng trn ng dn m giao thc nh tuyn Ip truyn thng xch

nh. Khi mt Router trong mng nhn c bn tin PATH, router skt hp thng tin trong bng nh tuyn,c xy dng bng cc giao thc nh tuyn nh OSPF, IS-IS v a chch trn gi dliu IP xc nh

bnh tuyn tip theo nhn bn tin ny.

Cn giao thc RSVP mrng vn sdng hai bn tin PATH v RESV xy dng LSP vi mc chtlng dch vtheo yu cu nhng ng i ca bn tin PATH v RESV l ng nh tuyn tng minh (

explicit route). Di y chng ta xem xt cu trc ca hai bn tin PATH v RESV.

a.Bn tin PATH: Vi giao thc RSVP mrng, bn tin PATH c thm mt thnh phn mi: ERO (

explicit route object). Sau y, chng ta tm hiu vba thnh phn chnh ca bn tin PATH:

Thnh phn yu cu nhn( Label request object) Thnh phn nh tuyn xc nh( Explicit route object) Thnh phn nh tuyn mnh tin ( Record route object)


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Thnh phn yu cu nhn ( LQO) :Igress LSR yu cu n nh nhn cho LSP cn xl, ngoi ra thnh phn cn mang gi trm nhn dng

giao thc lp mng L3PID ( Layer 3 protocol identifier) xc nh giao thc lp mng sdng. Nh ta

bit, c 3 loi nhn c sdng:

Nu giao thc lp 2 khng c cu trc xc nh th nhn c dng l nhn chn thm (shim label) nmgia tiu lp 2 v lp 3.

Nu giao thc lp 2 l ATM th gi trnhn cha trong vng thng tin VCI v VPI Nu giao thc lp 2 l Frame Relay th nhn c cha trong vng DLCI.

Khi nhn c bn tin PATH, cc LSR sgili trong khi trng thi ng dn ( Path State Block)

dnh cho LSP ny. Nu xch nh c loi nhn th stin hnh qu trnh n nh nhn.

Cc li c thxy ra:LSR nhn c bn tin PATH nhng khng n nh c nhn th n sgi bn tin PATH Error bovi igress LSR bit xy ra li nh tuyn hoc li ca n nh gi trnhn.

Nu LSR nhn c khng htrL3PID th sgi PATH Err cho igress LSR. Li ny xy ra sktthc qu trnh khi to LSP.

Nu nhn c bn tin ny m khng nhn ra c thnh phn yu cu nhn (Label request object) thcng gi PATH Err v kt thc khi to LSP.

Thnh phn nh tuyn xc nh ( ERO):

Thng tin trong thnh phn ny l ng i ca bn tin PATH trong mng. Cc LSR cn cvo thnhphn ny chuyn bn tin n ch nhn tip theo trong mng. ERO chsdng unicast v chkhi tt ccc

bnh tuyn trn ton tuyn u htrRSVP v ERO.

Cu trc ca ERO gm mt chui cc thnh phn ph( subobject). Mi thnh phn ny xc nh mt nhm ccnt mng hay chl mt nt mng trn ng nh tuyn hoc chra mt thao tc trn tuyn. Mi thnh phn

phnh thc gi l abstract node v nu chc duy nht mt nt mng th gi l Simple Abstract Node.Cc thnh phn phtrong mt ERO c thl nhng chsAS ( Autonomous System), trong mi AS c thcnhiu nt mng nhng chng hon ton trong sut i vi igress LSR. Di y l nh dng ca mt thnh

phn phtrong ERO:

Bit LLoi

(Type)

di

(Length)

Ni dung thnh phn ph

( Subobject content) Bit L =1: l mt ghp lng ( loose hop)

L =0: l mt ghp cht (strict hop) trn ng nh tuyn xc nh ( explicit route).

C 4 loi thnh phn ph(subobject) c nh ngha: Ipv4: cc nt mng trong abstract node c a chIP thuc phin bn 4. Mi a chc 32 bit. Ipv6: a chca mi nt mng thuc phin bn 6, 128 bit. Autonomous System Number: nhng nt mng nm trong abstract node cng nm trong mt AS.


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Thnh phn nh tuyn mnh tin ( RRO):

Vi thnh phn ny trong bn tin PATH, LSR sbit c tt ccc LSR nm trn ng i ca bn tinPATH ( cng chnh l LSP) tigress LSR n egress LSR. Khi igress LSR xy dng mt LSP, u tin, n sgi i bn tin PATH c cha thnh phn Label object v cthnh phn RRO. Thng tin cha trong RRO lc

ny chc a chIP ca igress LSR.

Khi mt LSR trung gian nhn c bn tin ny, LSR ssao li thnh phn RRO trong khi trng thi ngdn ( Path state block) v thm a chIP ca n vo trong thnh phn RRO. Ring egress LSR khi nhn cbn tin PATH shi p li bng bn tin RESV. Bn tin ny ssao li thnh phn RRO ca bn tin PATH. Nhvy, sau qu trnh trao i bn tin PATH v RESV, mi LSR sbit c ton bLSR thuc LSP ny. iu

ny rt hu ch cho cng vic qun trmng.

b. Bn tin RESV:

Bn tin ny dc egress LSR gi i trli bn tin PATH. Bn tin RESV mang thng tin vgi trnhnc n nh cng nh ti nguyn mng c dnh cho LSP ny. Trong phn ny, chng ta chxem xt thnh

phn chnh nhn ( Label object).

Thnh phn Label Object trong bn tin RESV

Khi nhn c mt bn tin RESV, LSR skim tra xem bn tin ny tng ng vi bn tin PATH no vLSR gi c phi l nt mng ktip thuc LSP hay khng. Khi tt cu hp lth LSR sn nh gi trnhntrong bn tin RESV cho vng nhn u ra (outgoing label). ng thi LSR cng gi i bn tin RESV vi gi tr

nhn sdng cho LSP ny ti LSR ngc dng.

Nh vy khi igress LSR nhn c bn tin RESV, lung lu lng xc nh c LSP dnh cho n. Qu

trnh n nh nhn cho LSP c thc hin di hnh thc downstream on demand.

c. Qu trnh xy dng LSP:


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nh tuyn IP truyn thng xc nh ng i ca dliu tigress LSR ( LSR 1) n egress LSR ( LSR

4) squa mt nt mng trung gian l Router A. Trong khi , nh tuyn c rng buc xc nh hng nhtuyn xc nh ( explicit route) cho dliu tLSR 1 n LSR 4 qua cc nt mng trung gian l LSR 2 v LSR

3. Sau y l qu trnh xy dng LSP trn tuyn nh tuyn ny.

Qu trnh gi bn tin PATH:

Ti LSR 1: LSR 1 gi i bn tin PATH v ba thnh phn chnh trong bn tin PATH:

Explicit route: m tng i ca bn tin PATH trong mng xy dng LSP v dnh sn tinguyn mng trn LSP ny.

Label request: a ra yu cu vgi trnhn dnh cho LSP. Record route: thnh phn ny trong bn tin gip igress LSR c c thng tin chnh xc vLSP nh

a chca cc LSR thuc LSP. Thnh phn ny rt thit thc trong vic khc phc hin tng lpvng.

Ti LSR 2:

Khi nhn c bn tin PATH, LSR 2 lu thnh phn Label request v Explicit route trong khitrng thi ng dn ( Path state block). ng thi a chIP ca LSR gi LSR 1, session, tpeccng c lu li sdng cho vic nh tuyn bn tin RESV tng ng vi LSR 1.

Cn cvo thnh phn Explicit route, LSR 2 chuyn bn tin PATH n LSR 3. Trong trng hp khng thn nh nhn cho LSP, LSR 2 sgi bn tin PATH Err bo li n

LSR 1

Ti LSR 3: Qu trnh tng tnh LSR 2.

Ti LSR 4: Nhn c bn tin PATH, LSR 4 it c n chnh l egress LSR v tin hnh gi bn tin

RESV vLSR 1.


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Qu trnh gi bn tin RESV:

Ti LSR 4:

LSR 4 n nh gi trnhn bng 0 cho LSP, a gi trnhn ny vo thnh phn Label ca bn tinRESV. L do LSR 4 sdng gi trnhn bng 0 l khi nhn gi dliu c nhn bng 0, LSR 4 sbit c n l egress LSR ca LSP, gnhn v nh tuyn gi bng cc giao thc nh tuyn IP

truyn thng. LSR 4 sdng thng tin Sender_Tpec ( Traffic Specification ) to ra thnh phn Receiver_Tpec (

Request Specification). ng i ca bn tin RESV c xc nh da vo thng tin lu li trongkhi trng thi ng ( Path state block).

Ti LSR 3:

Nhn c bn tin RESV, LSR 3 c thng tin trong thnh phn Label, lu gi trnhn bng 0 vvng nhn u ra ( Label out ) trong bng LIB. Vi nhng gi dliu n LSR 4 trn LSP ny,LSR 3 sgn vo gi gi trnhn bng 0.

LSR 3 sn nh mt nhn thch hp cho LSP ny. y, nhn ny bng 20, gn gi trny vobn tin RESV v gi n LSR 2.

Ti LSR 2: Qu trnh tng tnh LSR 3, v nhn c gn bng 10.

Ti LSR 1:

Khi nhn c bn tin RESV, qu trnh xy dng LSP kt thc. Vi nhng lung lu lng thchhp, LSR 1 sgn nhn bng 10 cho cc gi dliu chuyn ti LSR 2.

ng i ca gi dliu tigress LSR n egress LSR

Di y l qu trnh di chuyn trn LSP ca cc gi dliu sau khi kt thc qu trnh n nh nhn.


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LSR 1 l igress LSR, nhn cc gi dliu IP. Da vo thng tin trn tiu IP, LSR 1 nh dng li gidliu ph hp vi kthut lp lin kt dliu, gn nhn bng 10 v chuyn n LSR 2 trn int 2.

Nhn c dliu trn int 1 c nhn bng 10, LSR 2 da vo LIB xc nh c gi trnhn u ra.Trn hnh cho thy LSR 2 gi dliu c nhn bng 20 trn int 2 n LSR 3.

Qu trnh xl dliu ti LSR 3 hon ton tng tnh ti LSR 2. Dliu c gi n LSR 4 trn int2 vi gi trbng 0.

Nhn c dliu, vi gi trnhn bng 0, LSR 4 bit rng n l egress LSR. LSR 4 gnhn trn gidliu v nh tuyn bng cc thc nh tuyn IP truyn thng.3.2.1.2.Giao thc ginh trc ti nguyn RSVP-TE:Nhu cu sdng RSVP bt u t vic sdng mng IP vn chuyn cc lu lng thi gian thc nh

VoIP, Video Conference vn yu cu cht chvrng buc thi gian thc. m bo yu cu, cc ng dngsc t trc ti nguyn, tc ti nguyn khi ny sc dnh ring cho ng dng. RSVP nh ngha cch

t trc ti nguyn ny.

Nu yu cu ng k ti nguyn n bn gi v vic ng k QoS c thit lp ti mi router trnng i th trnh ng dng c thgi gi n bn nhn. Bphn loi v biu phi ti mi router gip cc

gi c chuyn i theo ng QoS c yu cu. Vic ng k ti nguyn chhp l khi tt ccc router trnng i cung cp RSVP. Nu c mt router cung cp vic ng k ti nguyn th dch vkhng thm bocho cng i. Mt router trn ng i khng cung cp RSVP ( tc chcung cp dch vtheo kiu Best-effort) slm tc nghn lung. Do , bn nhn khi u vic ng k ti nguyn c thyu cu mt thng ipxc nhn cho bit yu cu c c thit lp trong mng. Bn nhn c yu cu xc nhn trong bn tin RESVv nhn c bn tin RESVconf nu nh vic ng k c thit lp thnh cng. Vic ng k ti nguynRSVP c duy tr rt ngn ti cc router v cc host nn vic ng k sbhy bnu RSVP khng gi li

thng ip xc nhn dc theo con ng ng k ti nguyn tn ti.

Mrng RSVP-TE:RSVP-TE mrng khi nim lung lu lng cho con ng chuyn mch nhn. Do cc router c

chc nng RSVP sgn lu lng thnh cc lung da vo nhn MPLS.

Sa i mt slut cc thng ip chng v t trc ti nguyn c thtruyn gia cc router

u vo v u ra ( m theo RSVP l gia ngun v ch cui cng).


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Thm trng cho php bn tin tm ng t trc v nh xtrvcc gi trnhn.

Cho php router u vo chnh ra mt tuyn xc nh cho lung.

Thm mt sty chn tng thm tnh linh hot. Router c thdng RSVP-TE chphn phi nhnthm ch khi khng c nhu cu vdphng ti nguyn.

Cc bn tin RSVP v mrng cho RSVP-TE:

nh dng tiu ca RSVP

Phin bn ( Version): 4bit, hin ti l phin bn 1 C( Flags): 4 bit Loi bn tin ( Message type): 8 bit

1. PATH2. RESV3. PATH Err4. RESV Err5. PATH Tear6. RESV Tear7. RESV Conf

Kim tra li ( Checksum): 16 bit, bn nhn kim tra xem bn tin nhn c c li hay khng. Send TTL: 8 bit, c ngun gc tIP TTL. Nu IP TTL khng trng vi Send TTL th node trc khng

htrRSVP.

Dphng ( Reserved): 8 bit Chiu di ( Length): 16 bit, hin thchiu di ca ton bgi tin RSVP, tnh bng byte.

nh dng RSVP Objects

Chiu di ( length): 16 bit, chiu di ca phn RSVP Object


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Class Number: nh ngha mt Object class C-type: Gi trm c quy nh Class Number Object Data: Dliu c nh ngha bClass Number v C-type

Object NameLoi bn tinRSVP

M t

Adspec PATHMang dliu qung b: tr, bng thng,

thng siu khin tQoS

Detour PATHUsed in one-to-one backup to identify detour

LSPs

Error

PATH Err

RESV Err

RESV Conf

Xc nh mt li trong bn tin PATH Err vRESV Err hoc xc nhn trong bn tin RESVConf

Explicit Route PATH ng nh tuyn xc nh

Fast Reroute PATHc sdng to ng dphng cho LSP

chnh

Filter

RESV

RESV Tear

RESV Err

Xc nh ngun gc ca phin giao dch

Filter Spec RESVnh ngha mt nhm cc gi tin nhn cyu cu vQoS

Flow Spec RESV nh ngha yu cu vQoS

Hello Hello C thl mt yu cu hay hi p

HopPATH

RESV

Mang a chIP ca node gi bn tin (node c RSVP )v cng giao tip ng ra.

Integrity Tt ccc bn tinMang dliu xc thc ngun gc v mbo tnh ton vn ca bn tin RSVP

Label RESV Cha gi trnhn

Label Request PATH Yu cu ng k nhn

NullC Class Number l 0, khng c C-type, nidung sc bqua ni nhn.

Policy data

PATH

RESVPATH Err

RESV Err

Chnh sch vi dliu

Record RoutePATH

RESV

Danh sch cc a chIp m bn tin PATH iqua

RESV Conf RESV Hi p vxc nhn mt yu cu t ch


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RESV Conf

Scope

RESV

RESV Err

RESV Tear

Mang mt danh sch cc node gi vithng tin trong bn tin c chuyn tip

Sender PATHa chIP ca node gi v mt sthng tin

xc nhSession Tt ccc bn tin

Cha a chIP ch, giao thc IP v sport,xc nh mt phin lm vic cth

Session

AttributePATH

Cha cc thng s v u tin, c, ditn v tn phin.

Source Route PATHCha cc a ch trong phn nh tuyn xcnh ( ERO)

Style RESV Htrthng tin vvic t ch

TimePATH

RESVThi gian cho vic lm mi bn tin

Tspec PATH nh ngha tnh cht ca lung lu lng

3.2.2. Giao thc CR-LDP

CR-LDP l giao thc mrng ca LDP c thxy dng mt LSP trn tuyn nh tuyn xc nh

(explicit route) v dnh sn ti nguyn trn ton tuyn.

xy dng LSP trn tuyn xc nh, CR-LDP a vo mt thnh phn mi, c gi l ER (Explicit route).Cu trc cng nh cch thc xl thnh phn ny ti cc LSR hon ton tng tnh thnh phn Explicit

route ERO m ta cp trong phn RSVP mrng.

Qu trnh xy dng LSP, hay cn gi l qu trnh n nh nhn c thc hin di hnh thc xui dng theo

yu cu (downstream on demand) v sdng bn tin LDP Label Request. htrchc nng nh tuyn xcnh, bn tin ny c thm thnh phn ER.


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GisLSR 1 mun xy dng LSP tLSR1 n LSR4 v i qua LSR2, LSR3 :LSR1 ->LSR2 ->LSR3 ->LSR4v thc hin iu ny, LSR1 to ra thnh phn ER bao gm ba nt mng, cn c gi l abstract nodes :LSR2, LSR3, LSR4. Mi nt mng c c trng bng a chIPv4. Ch rng, mi a chIp nh thc thl a chca mt giao din no trn LSR (trong trng hp ny, a chIP gn lin vi mt giao din) hocl a chca ton bLSR. ng thi, LSR1 xy dng bn tin LDP Label Request v km theo thnh phn ERny. Sau khi c c bn tin hon chnh, LSR1 xc nhn LSR2 v nt mng u tin trong thnh phn ER nn

sgi bn tin ny n LSR2. Nhn c bn tin ny, LSR2 nhn bit c n l nt mng u tin cng nh lnt mng tip theo l LSR3 trong thnh phn ER. LSR2 shiu chnh li thng tin thnh phn ER bng cchxa i thng tin lin quan n n v gi bn tin Label Request n LSR3 trn kt ni gia LSR2 v LSR3. Vothi im ny trong thnh phn ER chcn hai nt mng l LSR3 v LSR4. Cch xl bn tin LDP LabelRequest ( cng nh siu chnh thnh phn ER) ti LSR3 hon ton tng tLSR2. Khi bn tin ny nLSR4, LSR4 nhn ra rng n l nt mng cui cng trong thnh phn ER. V th, LSR4 to ra bn tin LabelMapping v gi n LSR3. Bn tin ny bao gm thnh phn nhn v cc thnh phn khc. Khi nhn, LSR3 sdng gi trnhn trong bn tin n nh cho ng lin kt gia n v LSR4 dnh cho lu lng. Tip theo,LSR3 gi bn tin Label Mapping n LSR2 v cng tng t, bn tin ny c cha thng tin nhn. Ti LSR2,

cch thc xl bn tin ny cng ging ti LSR3. Cui cng, khi LSR1 nhn c bn tin ny th qu trnh xydng LSP kt thc.

ng thi vi thng tin nhn, giao thc CR-LDP sthng bo cho cc LSR bit c yu cu ti nguyngmng m lung lu lng cn c p ng. Thng tin ny c lu gitrong thnh phn thng slu lng

(Traffic Parameter). C 7 thng slu lng c nh ngha :

- Tc dliu nh PDR ( Peak data rate)- Kch thc chm cc i PBS (Peak burst size)- Tc dliu cc i CDR (Committes data rate)- Kch thc chm tha thun CBS (Committed burst size)- Kch thc chm vt ngng EBS (Excess burst size)- Tn s(Frequency)- Trng s(Weight)

Thng sPDR v PBS cho php xc nh tc ti a ca lung lu lng i trn LSP. Cn thng sCDR vCBS xc nh tc trung bnh ca lung lu lng. Cc LSR trn LSP ssdng nhng thng sny xc

nh ngun ti nguyn mng thch hp dnh cho LSP ca lung dliu.

3.2.3. Giao thc phn phi nhn rng uc nh tuyn CR-LDP tng c bn l mrng giao thc LDP htrcc con ng chuyn mch nhn rng buc CR

LSP bng cch nh ngha c chv cc gi trTLV bsung v da vo cc giao thc c sn tm ra tuyn

theo rng buc tha mn yu cu.

nh tuyn rng buc c thit lp nh mt hot ng u cui n u cui, t CR-LSR ng vo n CR-LSR ng ra, LSR ng vo sthit lp tuyn rng buc cho tt ccc nt tc ng c thdtrti nguynbng cch dng giao thc phn phi nhn. Thut ng rng buc m chrng mt siu kin phi c tha


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mn cho cc lin kt ga cc nt nh yu cu bng thng ti thiu hoc yu tan ninh. Giao thc tm ra nhngcon ng nh vy ( nh OSPF c sa i ) brng buc qung co v tm con ng trong min nh

tuyn tha mn cc rng buc ny.

Vi LDP, con ng chuyn mch nhn c thit lp ging nh l con ng ca chuyn tip IP bnh thng,LDP chthc hin vic phn phi nhn m thi. Vi CR-LDP, route ng vo c php chn ra hn mt con

ng hon chnh thay v chchn ra chng k. Vn l CR-LDP khng gip router ng vo bit c conng no l con ng tt nht cho mt lung xc nh no . Mt trong nhng cc thc hin l thm mt smrng c bit cho cc giao thc nh tuyn hin ti nh OSPF hay IS-IS chng mang thm thng tin trng

thi mng nh mc sdng bng thng hin ti, bng thng cc i c sn, mc u tin tng i

Khi , cc c thc hin nh sau :

1. Router ng vo tp hp thng tin trng thi mng

2. Mt lung yu cu ti nguyn t trc

3. Router ng vo tnh ton con ng cho lung ny

4. Router ng vo yu cu mt LSP r rng cho lung v nh xnhn cho con ng. y l chc nng

ca CR-LDP

5. Nu thnh cng, lung ssdng con ng chuyn mch nhn ny.

chnh con ng chuyn mch nhn y , router ng vo phi a ra mt tuyn r rng

trong bn tin yu cu nhn. Mi hop dc theo LSP ny c thl nghim ngt hoc lng lo ( strict hayloose). Nu l hop nghim ngt, n phi c chn l hop ktip ngay sau . Hop khng nghim ngt

linh hot hn do n c thl hop ktrc tip hoc qua nhiu hop trung gian ri mi ti n. Hopnghim ngt cho php con ng tht s c thc thay i sau ny. Nhng nu ta mun gichnhxc con ng nh lc u th ta phi gi yu cu c nh tuyn (route pinning) km theo.

Khi LSR xui dng trvthng ip nh xnhn, n thc hin xong vic t trc ti nguyn v

ng hm LSP c thit lp.

Cc thng ip nh tuyn rng buc v TLV:

LDP dng TLV m ha cc thng tin c mang trong thng ip LDP. Nh trong hnh di y, LDPTLV c m ha : 14 bit dng chloi m, 2 bit U, F chra cch thc thc hin khi m LSR khng nhn ra

loi TLV ny, trong chiu di 2 byte, trng cha gi trc chiu di thay i.

U F Loi Chiu di

Gi tr

Khi nhn mt TLV khng bit, nu bit U=0, mt thng bo sc gi vni xut pht thng ip vton bthng ip bbmc. Nu U=1, TLV bbmc mt cch im lng v phn cn li ca thng ip cxl nh khng c mt TLV khng bit . Cn btF chc p dng khi bit U c thit lp v thng ip


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cha TLV khng bit ny c chuyn tip i. Nu F=0, TLV khng c chuyn tip, F=1 th TLV khngbit ny c chuyn tip. Mi thxut hin trong thng ip LDP c thc m ha nh mt TLV nhngkhng phi lc no cng vy do n tn km khng gian v nhiu khi khng cn thit, v dkhng cn m ha

TLV nu chiu di ca gi tr l cnh v loi gi trny c bit.

Yu cu nhn (0x0401) Chiu di bn tin

ID bn tinFEC TLV

LSPID TLV (CR-LDP, bt buc)

ER-TLV (CR-LDP, ty chn)

TLV thng sluuy lng (CR-LDP, ty chn)

TLV cnh tuyn (CR-LDP, ty chn)

TLV lp ti nguyn (CR-LDP, ty chn)

TLV quyn u tin (CR-LDP, ty chn)

nh xnhn (0x0400) Chiu di bn tin

ID bn tin

TLV lp chuyn tip tng ng

TLV nhn

ID ca bn tin yu cu nhn

TLV LSPID (CR-LDP, ty chn)

TLV lu lng (CR-LDP, ty chn)

Nu giao thc phn phi nhn c dng cho nh tuyn rng buc, tuyn rng buc sc m ha bngmt chui cc chng ng r rng (explicit route hop) v c cha trong thng ip CR-LDP. Mi ER hopc thxc nh mt nhm cc nt trong tuyn ng bt buc v cc gi trTLV m tcc tham slu lngnh tc nh, tc cnh. Mt tuyn rng buc nh thny syu cu to ra con ng gm cc nt xc

nh ny v ng nh thtn xut hin trong TLV.

nh tuyn r rng (0x0800) Chiu di bn tin

ER-Hop t1 n n

Kiu Hop ER (gi trthay i) Chiu diNi dung

Tham s lu lng (0x0810) Chi u di bn tin = 24

C Tn s Dtr Trng lng

Tc dliu nh (PDR)


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Kch thc chm cc i (PBS)

Tc dliu tha thun (CDR)

Kch thc chm tha thun (CBS)

Kch thc chm vt ngng ( EBS)

CR-LDP cn htrvic cng chti nguyn, cho php mt thng ip yu cu nhn mi chim ly 1 tinguyn ang c sdng b1 LSP no nu yu cu mi ny c mc u tin cao hn con ng ny. Miyu cu nh xnhn c thcha chai gi trmc u tin khi to (cho lc thit lp LSP) v mc u tinchim gi(khi con ng thit lp ri). Hin c 8 mc u tin, cao nht l 0, thp nht l 7 v mc u tin

khi to ca mt CR-LDP khng nn cao hn mc u tin chim gi.

TLV mc u tin Chiu di = 4

u tin khto u tin chim d Dtr


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Chng IVCHUYN TIP LU LNG VO MPLS TE TUNNELSau khi to ra mt TE Tunnel, vn tip theo l lm sao chc chn rng n sc chuyn tip vo

trong ng hm. C 6 cch chuyn tip lu lng vo trong cc TE Tunnel, bao gm:

Static routing (nh tuyn tnh). Policy-based routing (nh tuyn da trn nn cc chnh sch). Autoroute annuonce (nh tuyn tng da trn vic thng bo). Forwarding adjacency (Ln cn chuyn tip). Direct mapping of AToM traffic onto TE tunnels (Ghp trc tip lu lng ca AtoM trn cc TE

Tunnel)

Class-based tunnel selection (la chn cc Class-based Tunnel)4.1. Static routing (nh tuyn tnh)

y l phng php n gin v dthc hin nht chuyn tip lu lng vo cc TE Tunnel. N

c cu hnh thit lp mt TE_LSP tu n cui ca tuyn LSP . Ngi qun trschnh cthcctuyn LSP no c sdng chuyn tip lu lng TE. Do , Static routing c u im l rt dthc hinnhng c nhc im l khng linh hot khi trin khai trong mt mng li rng ln.

4.2. Policy-ased routing (nh tuyn theo chnh sch)Policybased routing (PBR) sdng cc chnh sch thit lp trn cc giao tip ng vo vn

chuyn data sang cc hop kcn c xc nh trc. Cc TE LSP sc xc nh dvo cc chnh schv TE Tunnel sc thit lp da trn cc chnh sch ny. Khi thc hin PBR c th nh tuyn lu lngn mt TE Tunnel cthbng cch thit lp giao din m khng cn phi thay i bng nh tuyn.

4.3. Autoroute Announce (nh tuyn tng bng cch thng bo)Tunnel MPLS TE Autoroute announce l qu trnh iu khin thit lp cc giao dn ng hm trn cc

MPLS TE tunnel u v cui cc router v vy LSR c thtm thy cc c chIP ch, next hop v TETunnel nh l giao din ng ra trn bng nh tuyn. Vc bn, Autoroute Announce lm thay i thut tonSPF v vy LSR c thtm thy cc a chIP Prefix . Lc , headend-LSR c xem l c kt ni trc tipvi tailend-LSR qua mt TE-LSP, v vy lu lng i ti tailend-LSR v cc router pha sau tailend-LSR usdng TE-LSP lm giao din ng ra.

4.4. Forwarding adjacency (Ln cn chuyn tip).Phng thc ny cho php cc headend-LSR qung b cc TE-LSP nh l lin kt ca n. Nhng router

trong vng c thxt thm nhng TE-LSP ny nh l lin kt trong qu trnh tnh ton ng i. c thsdng phng thc ln cn chuyn tip th cn phi thit lp 2 ng TE-LSP gia 2 LSR, mi ng tngng mt hng v trn 2 LSR phi kch hot chc nng ln cn chuyn tip. Mt u im ca phng php nyl mt cp TE-LSP c xem nh l mt lin kt v c qung b trong min IGP, v mt router trong vngkhng chy MPLS TE cng c ththy lin kt ny v xem xt n trong qu trnh tnh tonng.V d: Chuyn tip lu lng trn cc TE Tunnel


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Vi c chnh tuyn IP, lu lng chuyn tip TR1 sang R7 schn tuyn ngn nht l R1, R2, R3,R7. Nu thit lp mt ng TE-LSP gia R2-R3 v mt ng na gia R4-R6 th lu lng vn chi trnTE-LSP R2-R3 bt chp TE-LSP R4-R6 c tt hn. Bi v lung lu lng chc chuyn tip vo TE-LSPti headend-LSR (R2 v R4) m cc router khc trong vng khng bit c stn ti ca 2 TE-LSP ny v nkhng c qung b. Nn khi lung lu lng i tR1 sang R7, R1 schuyn tip lu lng ti R2 v n tnhton c rng tuyn i ti u nht l i qua R2, ti R2 schuyn tip lu lng ln TE-LSP R2-R3.

Khi sdng ln cn chuyn tip, cc TE-LSP R2-R3 v R4-R6 c qung b nh l lin kt ca 4router R2, R3, R4, R6. Lin kt ny c qung b thng qua OSPF hoc IS-IS n router R1 v R7. R1 thmhai lin kt tng ng vi hai TE-LSP ny vo qu trnh tnh ton ng CSPF.Lc ny TE-LSP no c chiph thp nht sc R1 chn truyn lu lng, nu chi ph bng nhau th R1 sthc hin cn bng ti trncc TE-LSP ny.

4.5. Direct mapping of AToM traffic onto TE tunnels (Ghp trc tip lu lng ca AtoM trn cc TETunnel):

y l mt ng dng nng cao ca MPLS TE, cho php ng gi cc gi tinIPv4/IPv6, cc giao thc lp lin kt lp dliu ATM. Frame Relay, PPP, HDLC,

Ethernet, . Vo bn tin MPLS. N chcho php truyn theo phng thc im im, c cu hnh tiHeadend-LSR chnh cthlu lng ca loi giao thc no struyn trn TE-LSP no.

4.6. Class-based tunnel selection (la chn cc Class-based Tunnel)Cho php truyn lu lng ca cc lp dch v(CoS) khc nhau trn nhng TE-LSP khc nhau ca

cng mt cp Headend-LSR v Tailend-LSR. Router skim tra gi trIP-Precedence trong trng ToS ca

header IP hoc gi trEXP trong MPLS. Da trn gi trny, router squyt nh TE-LSP ph hp cho lunglu lng. Ta c 3 bit EXP tng ng vi 8 mc QoS, v vy ta c thnh x8 mc Qos ny n 8 TE-LSPkhc nhau gia 1 cp LSRs.


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L thuyt vMPLS Trafic Engineering

30

Chng VTI NH TUYN NHANH

5.1. Fast ReRouteTi nh tuyn nhanh

MPLS TE thng c trin khai trong mng li c dung lng lin kt rt ln. Nu mt lin kt hocmt router bsc, lu lng sc nh tuyn li i qua node sc. D vic nh tuyn li rt nhanh,thm ch chmt vi giy nhng n vn c thgy mt mt mt lng ln lu lng v dung lng ngtruyn rt cao. Vic gy nh hng rt nhiu n cc dch v, v dnh dch vVOIP.Mc d cc lin ktc khnng bo vti lp 1-v d, vi mt c chc gi l chuyn mch bo vtng (APS), l cp bo vtt nht ca MPLS . APS l mt c chni ting bo vkt ni quang. Mt bt li ca APS l milin kt bo vgm mt lin kt dphng v mt card nhn ri.Nu c scxy ra th lin kt quang hc bovny chuyn sang lin kt dphng.

Vic bo vcc lin kt v node vi TE th hiu quhn nhiu bi v n khng cn mt lin kt dphng

vt l. V vy, bo vlin kt v node khi sdng TE c chi ph rhn so vi phng php bo vca tuynquang. Mt ng hm dphng sc to trc nn skhng mt thi gian bo hiu thnh lp tuyn khithit bgp sc. C 2 c chthc hin vic bo vl: bo vlin kt v bo vnode. Hai phng phpnyu cung cp c chhi phc cc bv c mt im chung l: vic hi phc phi gn im bscnht .

Nh vy, n c thxl tng i nhanh v nh tuyn li tuyn LSP tlin kt bscsang ng dphng trong khong thi gian ngn khong hng chc ms.Khng chlu lng c iu khin sang ng dphng khi gp scm cbn tin bo hiu (RSVP) cngc chuyn qua ng dphng ng TE nh tuyn li vn c bo hiu.

5.2. FRR- Bo vlin kt (Link Protection)Bo vlin kt l bo mt lin kt cthc sdng cho TE-LSP. C ngha l tt ccc TE-LSP i qua

lin k c bo vbi mt ng dphng. Phng thc k thut ny cn gi l dphng linh hot(facility backup) bi v tt ccc tuyn TE-LSP i lin kt u c dphng bng mt lin kt khc.

V d: Lin kt R1-R2 (protected link) c bo vbng ng dphng R1-R3-R2 (NHOP BackupTunnel). ng dphng ny chbo vcc TE-LSP i qua lin kt theo chiu R1,R2, bo vtheo chiuR2,R1, cn cu hnh mt tuyn dphng khc tR2,R3,R1.

ng dphng hay cn gi l NHOP bypass backup tunnel lun lun bt u tim thay i ngtunnel gi PLR .R1 chnh l PLR (Point of local repair). Lin kt dphng lun kt ni ti NHOP router ,router ny l router cui ca lin kt.Router ny l im hp nht (R2 l MP)ca ng bo vv ng d

phng. ng dphng ny l mt tuyn tng minh c bo hiu bng RSVP, khi ng dphng cto, RSVP sbo hiu nhng nhn sc sdng.Trong v dny chc 2 hop v chng ta c thmrngnhiu hops nu cn.Khi ng dphng c to ra,RSVP bo hiu nhn nh bnh thng. Hnh di schochng ta thy rng R2 bo hiu cho R3 bng nhn 3 v R3 bo hiu cho R1 bng nhn 16 cho ng dphng.


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Khi qu trnh bo vkhng cn c sdng th cc gi tin c chuyn sang tunnel 1 lin kt gia R1v R2 c biu din hnh di.


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32

Cc gi tin trn LSP ca tunnel 1 chuyn n R1 vi nhn l 30 sau c hon i thnh nhn 33 khigi tin ri khi R1.Cui cng nhn 33 c chuyn thnh nhn 40 khi ra khi R2.Hnh di y schr khivn kt ni gp scth gi tin chuyn tR1 sang R2 sbhy.Ngay khi lin kt gia R1 v R2 bhy thPLR (R1) bt u gi lu lng tTE tunnel 1sang ng dphng NHOP qua R3.

Gi tin n R1 sc thay nhn 30 bng nhn 33 trc, sau R1 schng thm nhn 16 n R3 ca


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NHOP tunnel vo gi tin. Gi tin n R3 sc gnhn v chuyn ti R2 (MP). Ch rng nhn ca gi tin

ti R2 l ging nhau khi truyn qua lin kt R1-R2 hay i theo ng NHOP tunnel, chkhc l gi tin n R2bng giao tip vo khc nhau. V Router sdng khng gian nhn chung cho cc giao tip nn router chxtcc gi tin n cng nhn chkhng quan tm n tgiao tip no.

PLR chnn sdng ng dphng cho cc TE-LSP mt cch tm thi. V khi lin kt bsc, mt

bn tin PathErr sc PLR gi vcho headend-LSR ca TE-LSP . Khi headend-LSR nhn c bn tinPathErr n stnh ton v thit lp li ng i mi. Lc thnh lp xong tuyn mi th ng TE-LSP c angc truyn trn ng dphng skhng cn c dng na.

Khi headend-LSR nhn c bn tin PathErr th n sngt ng TE-LSP cho n khi TE-LSP c c nh tuyn li. V vy cn kch hot chc nng FRR trnh xy ra trng hp ny. Lc bn tinPathErr sgi thng tin chc nng phc hi cc b(Local Repair). Thng ny ny sbo cho headend-LSRrng n khng nn ngt TE-LSP dphng Tunnel ny trong khi ang nh tuyn li v nu Tunnel ny bngtth slm mt lu lng ca hthng.

IGP cng bo hiu l ng chnh bhng.Khi PLR sdng ng dphng nh tuyn ng bo

vLSP,PLR sgi bn tin PATH ca ng bo vi trn ng dphng hay khi ng dphng c sdng.

Mt bt li khi sdng phng php bo vlin kt l NHOP tunnel bo vcho ton lin kt. Nh vytng bng thng qua lin kt ti mt thi im c thrt ln, m ng dphng khng thit lp dnh ringbng thng cho trng hp ny, nn c thn skhng bng thng khdng chuyn ton blu lngtlin kt bscqua n v c thdn n mt gi. Nhng do vic sdng ng dphng chl tm thi headend-LSR nh tuyn li ng khc, nn FRR c thkhng hon ton bo vc lung lu lng trn

lin kt bscnhng cng c thchp nhn c trnh trng hp mt ton blu lng.Vic nh tuyn li ti headend-LSR c thkhng tm c mt tuyn ph hp trong trng hp mt TE

tunnel chi theo mt tuyn tng minh m khng c mt tuyn ng.Nu lin kt bo vbdown th lin ktdphng sc sdng ngay.Bi v headend khng thtnh ton 1 ng no khc i trong mng. giiquyt vn ny th c thcu hnh mt tuyn ng vi chscao hn tuyn tng minh. Lc khi nhtuyn li th headend-LSR sc c mt tuyn thay thkhc.

ng dphng c cu hnh sn trn cc brouter PLR.Chng ta c thchnh ng dphng vigiao din lnh mpls traffic-eng backup-pathvo tuyn lin kt bo v. Chng ta c thcu hnh cc ng dphng vi tuyn tng minh tPLR n router next-hop.Khi Router headend nm trn lin kt bo v, chng taschthtuyn ng no c sdng lm ng dphng (fast reroute) vi cu lnh tunnel mpls traffic-eng fast-reoute. Lnh ny t cSession vi thuc tnh l 1 chra rng tunnel mun c bo v.Thng thng chng ta khng nn sdng ng dphng. V ng dphng skhng thng bo vic t

ng vic nh tuyn hay thay i cu hnh. Bn cnh chngta phi m bo cc lin kt bo vv cc linkt trong ng dphng khng chia sti nguyn ging nhau.Chng ta c thcu hnh cc ng dphngbng nh tuyn tnh. Tuy nhin, chng ta cng c thcu hnh n nh mt ng loi tr. y l mt tuyntng minh v ta c thloi trmt hop (mt LSR). Vi ng dphng ta phi loi bcc lin kt bo vkhi nhng tuyn chnh.


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5.3. FRRBo VNode (Node Protection)Vi nh tuyn nhanh trong bo vnode th n c thbo vton blin kt ca node . Nguyn l

hot ng ca bo vNode kh ging vi bo vlin kt. N sto mt ng dphng chng kktip(NNHOP) kt ni trouter PLR n router nm sau router c bo v. Khi chng ta cu hnh vi cu lnhtunnel mpls traffic-eng fast-reoute node-protect trn headend ca tuyn th headend ny sbt ln c0x10

nm trong bn tin PATH, chthrng n mun bt Node bo v.

C 2 vn lm cho vic bo vnode phc tp hn bo vlin kt. Ban u khi sdng ng hm dphng, cc gi khng n NHOP LSR (berlin) na m n NNHOP LSR (Rome), v vy PLR phi hc li nhngi tin n NNHOP LSR (Rome) ging vi gi tin m (berlin) c trc . gii quyt vn ny , thnhn n NNHOP LSR c gn trong trng subobject ca RRO object trong bn tin RESV gi tNNHOPLSR n PLR. Khi sdng ng dphng, cc gi tin n PLR ny thi n si nhn n bng nhn cang dphng NNHOP.

Vn tip theo l ng dphng khng i qua node c bo v, mc d thng tin ERO trong bn tin

PATH vn gia chca node . V vy ng dphng trnh i qua node c bo v th cn chnh router ID ca node cn loi btrong tuyn tng minh.Ngoi ra PLR vn cn phi gi bn tin PATH n cc router thuc ng hm NNHOP duy tr hot

ng.V d: Mt TE-LSP Tunnel1 i trouter (paris) n router (Sydney) theo tuyn Paris, brussels, berlin, rome,sydney. ng dphng NNHOP i trouter (Brussels) (PLR) qua router (Frankfurt) ti router (rome) MP).ng hm dphng skhng i qua router c bo vl router (berlin).


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35

Cc gi tin c nhn 33 i tParis, brussels, ti brussele si nhn thnh 30 v chuyn tip ti router(berlin), ti router (berlin) tip tc i nhn v chuyn tip ti router ti (Rome),sau n gnhn vchuyngi tin IP ti Router ti (sydney)

Khi Router ti (berlin) bscth n schuyn qua sdng ng dphng NNHOP.Cc gi tin tParis chuyn sang sc router ti (brussel) i nhn n NNHOP (Rome) l nhn 31 m nhn ny c cbo hiu trong bn tin RESV. Sau router ti (brussel) schng tip thm mt nhn 17 ti router ti(frankfut). Ti router (frankfult) khi nhn cc gi tin trouter(brussel) sgnhn v chuyn tip gi tin tirouter(rome). Nh vy gi tin ti router ti (rome) u mang nhn 31 trong c2 trng hp trc v sau khi sdng NNHOP backup tunnel


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36

BI M PHNG TRN GNS3

Cc ni dung lm c :

To tunnel; xem xt trng thi cc bn RIB, FIB, LIB, LFIB khi thay i cc thuctnh: banwidth, attribute-flag; Load-balancing

a chIP ca cc cng c t ging nh hnh.

Cc cng loopback trn cc router u l loopback 0 v c t theo nguyn tc:

R1--> 1.1.1.1 255.255.255.255

R2-->2.2.2.2 255.255.255.255

.........Mc ch ca m phng l:

-Xy dng cc ng tunnel trong MPLS-TE gm ng Dynamic v Explicit.

-Thy c u im ca MPLS-TE: load balancing, FRR: link protection v node protection...

-Thay i cc c tnh thy sthay i ca dynamic tunnel.


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Cc c cu hnh c n cn c:

Bc 1: Cu hnh a chLoopback v a chcc cng trn cc Router

Cu hnh a chLoopback:

- Router#configure terminal- Router(config)#interface Looback 0- Router(config-if)#ip address {ip-address}Cu hnh a chcng:

- Router#configure terminal- Router(config)#interface {number interface}- Router(config-if)#ip address {ip-address}- Router(config)#no shutdownBc 2:Sdng MPLS TE trn Router v cc cngKch hot trn Router:

- Router(config)#mpls ip- Router(config)#mpls trafic-eng tunnelsKch hot trn cng:

- Router(config)#interface {type} {number interface}- Router(config-if)#mpls ip-

Router(config-if)#mpls trafic-eng tunnelsBc 3:Cu hnh bng thng dnh ring ca cc cng sdng MPLS TE bo hiu v

phc vtin trnh dnh ring ti nguyn cho ng hm (Tunnel).

Cu hnh bng thng dnh ring v lung lu lng ln nht c i qua:

- Router(config)#interface {type} {number interface}- Router(config-if)#ip rsvp bandwidth 256 256Bc 4:Cu hnh giao thc nh tuyn OSPF

- Router(config)#router ospf 1- Router(config-router)#network {ip address} {wild-card mask}area 0- Router(config-router)#mpls traffic-eng area 0- Router(config-router)#mpls traffic-eng router-id loopback 0Bc 5:Cu hnh thit lp ng hm TE-LSP


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Cu hnh cng cho ng hm:

- Router(config)#interface tunnel {number}Cu hnh a chcng ca ng hm l cng Loopback:

- Router(config-if)#ip unnumbered loopback {number}Cu hnh a chch ca ng hm:

- Router(config-if)#tunnel destination {ip address}Cu hnh chhot ng ca ng hm:

- Router(config-if)#tunnel mode mpls traffic-engCu hnh ctrng thi cho ng hm :

- Router(config-if)#tunn mpls traffic-eng affinity 0x1 mask 0x3Sau trn mi interface m tunnel si qua ta cu hnh lnh:

- Router(config-if)#tunnel mpls traffic attribute-flag 0x1Cu hnh thng sbng thng cn thit cho ng hm

- Router(config-if)#tunnel mpls traffic-eng bandwidth {kbps}Cu hnh cthuc tnh phn lp ti nguyn cho ng hm

- Router(config-if)#tunnel mpls traffic-eng priority {setup priority-value} {holdpriority-value}

hnh ty chn thit lp ng hm (ng hoc tng minh)

- Router(config-if)#tunnel mpls traffic-eng path-option {priority} {dynamic| explicit{name {LSP name} } }

Bc 6:Nu ty chn thit lp ng hm l tng minh th ta phi chr a chIP ca

cc Router m ng hm si qua.

- Router(config)#ip explicit-path name {LSP name}enable- Router(cfg-ip-expl-path)#next-address {ip address}- Router(cfg-ip-expl-path)#next-address {ip address}

Link protectionGinh tnh hung lin kt gia R6 v R7 bhng, ta scu hnh tt ccc Tunnel i qua lin kt nychuyn hng tR6=>R4=>R7

R6: ra scu hnh 1 tunnel c tn l backup vi explicit path tR6=>R4=>R7:

- R6(config) int tunn 999


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- R6(config-if) ip unnumber loopback 0- R6(config-if) tunnel destination 7.7.7.7

tunn mode mpls traffic-eng- R6(config-if) tunnel mpls traffic-eng path-option 1 explicit name backup- !- R6(config) int g0/0- R6(config-if) mpls traffic-eng backup-path tunnel 999- !- R6(config) ip explicit-path name backup- R6(config-if) next-address 10.1.46.4- R6(config-if) next-address 10.1.47.4- R6(config-if) next-address 10.1.47.7- !- R1(config) int tunnel 1- R1(config) tunnel mpls fast-reroute

Sau khi thc hin cc bc trn cho tng router th dng lnh Show run xem cc thng sc ci t trn cc router. Di y l kt quShow runca cc router.

Router 1:


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Thng tin cthca tng tunnel trn R1:


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Router 2:


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Router 3:


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Router 4:


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Router 5:


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Router 6:


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Router 7:


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Cu hnh load balacing trn cc tunnel:

Ta cu hnh lnh :tunnel mpls traffic-eng autoroute announce trn cc tunnel c cng a chch l 7.7.7.7.

Sau khi cu hnh xong ta dng lnh Show ip route 7.7.7.7

Ta thy: trouter 1 ti router 7 c 4 ng cng metric v cng load balancing vi nhau.


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Xem cc bng:

Bng RIB (Routing Information Base): trn R2

Ta dng lnh : Show ip ospf 1 rib:


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Bng ny c ly trouter 2.

Bng ny cho ta bit router 2 hc c cc mng no thng qua cng no v interface no (davo VIA), ngoi ra cn cho bit cost ca ng link v area ca mng.

V d: ta c ththy mng 10.34.0/24 c cost l 2, thuc area 0 v c router 2 hc thng qua

interface g1/0 c a chl 10.1.23.3 .

Bng FIB (Forwarding Information Base): trn R2

Ta dng lnh show ip route


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Bng ny cho ta bit ng i n 1 mng c ththng qua con ng no v qua interface no.

VD: Mun ti mng 10.1.46.0/24 c 2 ng l qua 10.1.25.5 v 10.1.23.3 .

Bng LIB (Label Information Base):trn R2

Ta dng lnh Show mpls ldp bindings.


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Bng LIB cho ta bit sng i ti 1 mng v nhn tng ng vi ng i , ngoi ra LIBcn cho ta bit local label.

VD: mun i ti mng 10.1.47.0/24, ta c 3 ng (qua R1, R3 hoc R5) ng vi 3 nhn(22,27,33).


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Dng Wireshark bt cc gi tin:

Gi tin OSPF LS update:

Gi tin OSPF LS acknowledge:


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Gi tin RSVP Path:

Gi tin RSVP RESV:

Documents

Bao Cao Mpls - Nhóm 2 - d10vta1