chuyen mạch_MPLS [Compatibility Mode]

7/31/2019 chuyen mch_MPLS [Compatibility Mode]

1/40

Khoa VT2-B mn Chuyn Mch 5/10/20

Nguyn Xun Khnh

11

Multi Protocol Label SwitchMulti Protocol Label Switch

(MPLS)(MPLS)

2

Ni dung :

Gii thiu

nh tuyn v chuyn mch

Mt bng iu khin v mt bngchuyn tip

Cc thnh phn ca MPLS

Giao thc phn phi nhn


2/40


Nguyn Xun Khnh

3

Gii thiu v MPLS

4

MPLS l g ?

L mt cng ngh kt hp nh tuyn lp 3 (IP) v

chuyn mch lp 2 (ATM,FR, Ethernet)

Chuyn tip gi tin bng cch gn nhn c chiu di

c nh v ngn vo gi tin

Cc gi MPLS c th chy trn cc cng ngh lp 2

khc nh : ATM,FR, POS, PPP

Cung cp c ch chuyn mch hng kt ni

MPLS l mt cng ngh phn phi cc dch v trn

nn IP


3/40


Nguyn Xun Khnh

5

L do pht trin MPLS

Tc v tr ca IP

Kh nng tng thch vi s pht trin kch c mng

Tnh n gin

S dng ti nguyn mng

K thut lu lng

Tch hp IP v ATM

6

Tc v tr

IP

nh tuyn IP cn mt

lng ln hat ng

tm kim cho mi gi IP

bin ng tr ln

MPLS

Qu trnh tm kim trong

MPLS da vo ch s v

ch cn mt ln truy xut

bng tm kim

bin ng tr nh


4/40


Nguyn Xun Khnh

7

Tc v tr (tt)

8

Tng thch vi s pht trinmng

Internet mi ngy c hng ngn user v node

mng mi to ra mt khi lng cng vic

ng k cho router

MPLS cho php nhm mt s lng a ch IP

kt hp vi mt hoc vi nhn


5/40


Nguyn Xun Khnh

9

Tnh n gin

chuyn tip gi tin

yu cu mt s hat

ng tm kim trn

bng tm kim

S chuyn tip gi tin

ch da vo nhn.

S phc tp ch nm

giai an u trong qu

trnh kt ni (thit lp

LSP, gn nhn)

10

K thut lu lng

nh tuyn IP khng phi lun hiu qu

Chuyn mch nhn cho php cc con ng qua mng c

iu khin tt hn

V d :


6/40


Nguyn Xun Khnh

11

(Forwarding Equivalence Class): tp hp cc lut xc nh

mt nhm cc gi lp mng c th s c chuyn tip theo cn

mt con ng v cch thc nh nhau qua mng

(Label Switching Router) node mng c chc nng x l

nhn ( chuyn nhn, gn nhn), n c th l mt b nh tuyn IP

hoc mt b chuyn mch ATM h tr

12

: l header ca gi tin c gn vi mt FEC no .

(Label Distribution Protocol) l mt giao thc c trch nhim

to ra mi quan h (php gn) gia FEC v nhn chy trong

thit b LSR v chc nng phn phi nhn cho cc lung thng

tin qua mng.

LSP ( Label Switching Path) l mt con ng i qua mng cho

mt lung thng tin. N bt u t mt LSR li vo mng, quacc LSR trung gian nm trong mng v kt thc LSR li ra.


7/40


Nguyn Xun Khnh

13

Hot ng chuyn mch ca MPLS

Nhnvo

Giaotip vo

FEC Giaotip ra

Nhnra

- 2 160.100.0.0

1 5

- 2 125.100.0.0

1 20

LSR li vo

160.100.1.5

LSR li raIP Network

IP Network

160.100.0.0

Nhnvo

Giaotip vo

FEC Giaotip ra

Nhnra

5 2 160.100.0.0

1 8

20 2 125.100.0.0

3 30

Nhnvo

Giaotip vo

FEC Giaotip ra

Nhnra

8 1 160.100.0.0

3 3

-

Nhnvo

Giaotip vo

FEC Giaotip ra

Nhnra

3 1 160.100.0.0

2 -

12 2 1

3

1 3

2

1 2

160.100.1.5

5 8 3

IP Network

150.104.0.0

LSR A LSR B LSR C LSR D

LSR ILSR HLSR GLSR F

LSR J

LSR E

2

1

4

3 1

2

14

Mt s khi nim c bn


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Nguyn Xun Khnh

15

Chuyn mch v nh tuyn Chuyn mch/chuyn tip :

s dng mt bng nh tuyn hoc mt bng nhn a

ra quyt nh chuyn tip

nh tuyn :

s dng hat ng thng bo tuyn c c s hiu

bit v mng v to ra cc bng nh tuyn/ bng nhn s

dng trong qu trnh gi chuyn tip gi tin

16

Chuyn mch

Chuyn mch lp 2 : Bridge dng trong LAN, ATM,FR

Chuyn mch lp 3 : chuyn mch da trn a ch

IP, s dng phn cng c thit k c bit, vd :

ASIC ( Application-Specific Intergrated Circuit)

Chuyn mch lp 4 : chuyn mch da trn a ch IP

v s cng (TCP/UDP) hoc PID (protocol IDentifier)


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Nguyn Xun Khnh

17

nh tuyn

Gm 2 thnh phn phn bit : Thnh phn chuyn tip

(forwarding) v thnh phn iu khin ( control)

Chuyn tip

Chuyn tip gi da trn thng tin trong bng chuyn tip v

header lp 3

iu khin

Xy dng v duy tr bng chuyn tip

Giao thc nh tuyn : OSPF, IS-IS, BGPDng cc gii thut nh tuyn : Dijkstra, Bellman Ford

chuyn i bng topology thnh bng chuyn tip

18

Chuyn mch v nh tuyn

nh tuyn

Tin trnh thit lp con

ng i qua mng

Da vo s phn tch

header ca lp 3

Dng bng nh tuyn, c

thit lp do giao thc nhtuyn

Hat ng chm hn

Chuyn mch

Tin trnh chuyn tip gi

tin ra ng cng ra ca n

Da vo s phn tch

header ca lp 2

Dng bng chuyn mch,

c thit lp trc tthng tin iu khin kt ni

Hat ng nhanh hn


10/40


Nguyn Xun Khnh

19

Mt bng iu khin v mt bngchuyn tip

Network layer

Routing Control Plane

Datalink layer

Data Forwarding Plane

Physical layer

Internet

IP router

input/output

20

Mt bng iu khin v mt bngchuyn tip (tt)

Network layer

Datalink layer

Physical layer

Internet

IP router

Routing Control Plane


11/40


Nguyn Xun Khnh

21


22



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Nguyn Xun Khnh

23

Chc nng ca cc mt bng iu khinv mt bng chuyn tip trong MPLS

Mt bng iu khin

- nh tuyn v to thng tin chuyn tip

- - Thit lp cc LSP tng ng vi FEC

Mt bng chuyn tip

- Han i nhn

- Gn v lai b nhn

- x l chng nhn

- Chuyn tip gi tin

24

Kin trc node MPLS

C 2 mt bng : mt bng chuyn tip MPLS v mt bng

iu khin MPLS

C th thc hin nh tuyn lp 3 v chuyn mch lp 2

(chuyn mch gi c gn nhn)


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Nguyn Xun Khnh

25

Kin trc node MPLS (tt)

Mt bng chuyn tip :

- Chuyn tip gi da vo gi tr nhn v c s d liu

thng tin chuyn tip nhn LFIB (Label Forwarding

Information Base).

- Mi node MPLS duy tr 2 bng cho hat ng chuyn tip

: LFIB v LIB (Label Information Base)

- LIB cha tt c cc nh x gia nhn do node cha LIB

to ra v cc nhn nhn c t cc node lng ging

- LFIB ch cha mt tp con cc nhn cha trong LIB dngcho hat ng chuyn tip gi tht s trn mt LSP . LFIB

tng ng vi bng chuyn tip trong IP

26

V d v LIB

LIB


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Nguyn Xun Khnh

27

V d v LFIB

LFIB

28

Quan h gia cc mt bng iukhin IP v MPLS


15/40


Nguyn Xun Khnh

29


Hot ng chuyn tip :

E F f .g .h .iD f .g .h .i

D e .f .g .hC e .f .g .h

B a .b .c .d

A d .e .f .gA b .c .d .e

IN IF IN LBL OUT IF OUT NHLFE

a.b.c.dd.e.f.g

b.c.d.e

a.b.c.da.b.c.d

FEC OUT IF OUT NHLFEIP

Packets

IP

Packets

Labeled

Packets

Labeled

Packets

30


Mt bng iu khin

- C trch nhim to v duy tr LFIB bng cch

qung co, phn phi nhn v a ch, v to mi

tng quan gia chng.

- Tt c cc node MPLS phi chy mt giao thc

nh tuyn IP. Nh OSPF, IS-IS..

- Thng tin gn nhn c phn b nh mt giao

thc phn phi nhn nh LDP, RVSP,BGP


16/40


Nguyn Xun Khnh

31

Lp tng ng chuyn tip (FEC)

Miu t s kt hp cc gi tin c th vi mt a ch

IP/mt lp lu lng

Dng nhn nhn din mt FEC c th.

FEC c th thit lp da vo

-a ch IP ngun v a ch IP ch

- S cng ngun v cng ch

- Nhn din giao thc PID (Protocol Identifier)

-im m (code point) ca dch v phn bit (differentiated

Service) trong IP4

- Nhn lung trong IP6

32

Ti sao dng FEC ?

FEC cho php gom nhm lu lng thnh cc lp,

to iu kin phn bit cc lung lu lng khc

nhau i qua mng .

FEC c th h tr hat ng cht lng dch v trn

mng


17/40


Nguyn Xun Khnh

33

Header MPLS

Ty thuc vo cng ngh lp 2 :

ATM : nhn MPLS l VPI,VCI

FR : nhn MPLS l DLCI

Ethernet, PPP..: header MPLS c chn giaheader lp 2 v header lp 3 (Shim Header)

34

Header MPLS (tt)

Cu trc Header MPLS

Label Value : 20 bit (0-19), gi tr 0 1.048.575, cc gi tr c bit 0 15

EXP (Experimental) : 3 bit (20-22) dnh ring cho nghin cu, thc nghim

hoc phn bit cht lng dch v.

S (Stack) : 1 bit (23) dng trong hat ng chng nhn

TTL (Time to Live) : 8 bit (24-31), gii hn s hop gi MPLS i ngang qua


18/40


Nguyn Xun Khnh

35

Header MPLS (tt)

Cc thao tc trn nhn : c 3 thao tc c bn

- Push : t nhn MPLS vo gi lp mng. Lun thc

hin LSR li vo

- Pop : ly nhn ra khi gi tin. Thc hin LSR li ra

- Swap : Han i nhn, da vo LFIB thay i nhn

c bng mt nhn mi. Thc hin LSR trung gian

36

Header MPLS (tt)

Khng gian nhn : c 2 cch t chc khng giannhn

- Khng gian nhn trn giao tip - Khng gian nhn trn thit b


19/40


Nguyn Xun Khnh

37

V d: To v x l header MPLS

y1

38

Chng nhn (Label Stack)

Gi MPLS c kh nng mang nhiu nhn

Nh chng ta bit nhn tng ng vi FEC.

Vd : Mt nhn nh tuyn gi ti im ra,

mt nhn khc phn bit gi ca khch hng

A vi gi ca khch hng B.

Cc nhn bn trong ch nh cc dch v/

FEC, vd : VPN, Fast Re-route

Nhn bn ngai dng chuyn mch cc gi

MPLS trong mng

Nhn trong cng trong chng nhn c bit S=1


20/40


Nguyn Xun Khnh 2

39

V d Chng nhn

40

V d Chng nhn


21/40


Nguyn Xun Khnh 2

41

V d Chng nhn

42

S tp hp cc FEC (Aggregation)

Gp nhiu FEC vo chung mt nhn

Gim s lng nhn v s lng lu thng LDP


22/40


Nguyn Xun Khnh 2

43

S tp hp cc nhn (Merge)

Nhiu gi n vi nhng nhn khc nhau c th c

gn cng mt nhn trn cng mt giao tip ra

44

Cc thnh phn ca MPLS


23/40


Nguyn Xun Khnh 2

45

Cc thnh phn ca MPLS bao gm

B nh tuyn chuyn mch nhn LSR (Label

Switched Router)

ng chuyn mch nhn LSP (Label

Switched Path)

Giao thc phn phi nhn LDP (Label

Distribution Protocol)

46

LSR

L thit b thc hin cc thnh phn chuyn

tip v iu khin MPLS

Chuyn tip gi da trn gi tr nhn ca gi

Theo mode hot ng LSR c 2 lai : MPLS-

enabled router (frame mode MPLS) v MPLS-

enabled ATM switch (cell mode MPLS).

Theo v tr trong mng LSR c 3 lai : Ingress

LSR, Transit LSR v egress LSR


24/40


Nguyn Xun Khnh 2

47

LSR (tt)

48

LSR (tt) Ingress LSR (Edge LSR)

-Nhn lung thng tin a vo ca user (vd IP) v phn lai

vo mt FEC

- To mt header MPLS v gn mt nhn

- Gn header MPLS vo gi IP hnh thnh mt PDU MPLS

Transit LSR (core LSR)

- Nhn PDU v da vo header MPLS a ra quyt nh

chuyn tip

- Thc hin han i nhn

Egress LSR (Edge LSR)

G b header MPLS


25/40


Nguyn Xun Khnh 2

49

Cc lai hat ng ca LSR

Aggregate : Tp hp cc lung cng mt c tnh no

thnh 1 lung chung (gn chung mt nhn)

Pop : Lai b nhn trn cng v pht phn ti tin cn li

nh l mt gi c gn nhn hoc gi IP khng gn nhn

Push : thay th nhn trn cng trong chng nhn bng

mt tp cc nhn

Swap : thay th nhn trn cng bng mt nhn khc

Untag : Lai b nhn trn cng v chuyn tip gi IP ti

chng IP k

50

Hat ng ca Packet-Based LSR-chngnhn n


26/40


Nguyn Xun Khnh 2

51

Hat ng ca Packet-Based LSR- chngnhn a cp

52

Hat ng ca ATM LSR


27/40


Nguyn Xun Khnh 2

53

LSP

L mt kt ni c cu hnh gia 2 LSR. Trong k

thut chuyn mch nhn c dng chuyn tip gi

LSP l n hng.

LSP c xc nh qua tp cc nhn trn cc chng

ca LSP t LSR li vo n LSR li ra.

C th c nhiu LSP khc nhau nhiu cp nhn khc

nhau (chng nhn)

LSP c thit lp nh giao thc phn phi nhn LDP

iu khin thit lp LSP c 2 phng php : iu khinc lp v iu khin c th t.

54

2 phng php iu khin thit lpLSP

iu khin c lp

LSR t chn mt nhn trong s nhn cha s dng ca n trong

LIB (Label Information Base) cho mt FEC c th v cp nht

LFIB. Sau , thng tin kt nhn cc b ny s c thng bo

ti cc LSR lng ging ca n s dng LDP.

iu khin theo th t

Vic gn nhn c thc hin theo th t t LSR li ra n LSR

li vo ca LSP. Vic thit lp LSP c th bt ngun t LSR livo hay LSR li ra. Phng php iu khin ny yu cu cc

thng tin kt hp nhn lan truyn qua tt c cc LSR trc khi

thit lp LSP


28/40


Nguyn Xun Khnh 2

55

V d v iu khin c lp

172.16.0.0/16

In

lable

Out

lable

inf

172.16.0.0/16

Inlable

Outlable

inf

172.16.0.0/16

Inlable

Outlable

inf

172.16.0.0/16

In

lable

Out

lable

inf

56

V d v iu khin c lp172.16.0.0/16

In

lable

Out

lable

inf

50 S0

172.16.0.0/16

In

lable

Out

lable

inf

25 S1

172.16.0.0/16

In

lable

Out

lable

inf

45 S1 172.16.0.0/16

Inlable

Outlable

inf

33 E0

L=50 cho

172.16.0.0

L=25 cho

172.16.0.0

L=45 cho

172.16.0.0

L=33 cho

172.16.0.0


29/40


Nguyn Xun Khnh 2

57

V d v iu khin c lp

172.16.0.0/16

In

lable

Out

lable

inf

50 25 S0

172.16.0.0/16

Inlable

Outlable

inf

25 45 S1

172.16.0.0/16

Inlable

Outlable

inf

45 33 S1 172.16.0.0/16

In

lable

Out

lable

inf

33 E0

L=50 cho172.16.0.0

L=25 cho

172.16.0.0

L=45 cho

172.16.0.0

L=33 cho

172.16.0.0

58

V d v iu khin theo th t

LSR 1

LSR 5LSR 4

LSR 6

S2

LSR 2 LSR 3

172.16.0.0/16

S0

S2 S2

S2

S1

S1

S1

S1

S1

S0S0

S0

S0

LSR 7

E0

S2

S0

Label =66

Label =7

Label =11

Label =33

Label =22

Label =33


30/40


Nguyn Xun Khnh 3

59

LDP

S dng kt hp vi cc giao thc nh tuyn

phn b thng tin gn nhn gia cc thit b LSR.

Phn phi nhn dng giao thc vn chuyn TCP

(cng 646).

LDP gip thit lp LSP bng cch dng mt s

th tc phn phi nhn gia cc LSR ngang

cp

60

Giao thc phn phi nhn


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Nguyn Xun Khnh 3

61

Cc giao thc phn phi nhn

LDP (Label Distribution Protocol)

CR_LDP (Constraint-based LDP).

RSVP ( Resource Reservation Protocol).

BGP (Border Gateway Protocol)

MPLS khng qui nh mt giao thc phn phi

nhn c th

62

Gii thiu LDP

RFC 3035 v 3036

Xc nh FEC cho cc lai gi lp 3.

Xc nh cc lng ging c kh nng MPLS

Thng lng nhn gia cc LSR ngang cp.

Cc ngang cp LDP (LDP peer) l cc LSR dng LDP

trao i nhn v thng tin nh x FEC.

C th hat ng gia 2 LSR k cn hoc khng k cn

nhau.

Cc phin lm vic LDP theo 2 chiu


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Nguyn Xun Khnh 3

63

Gii thiu LDP (tt)

64

Cc lai bn tin LDP


33/40


Nguyn Xun Khnh 3

65

Cc lai bn tin LDP (tt)

Discovery : thng bo v duy tr s tn ti camt LSR trn mng, dng UDP

Session : thit lp, duy tr v xa cc phin lmvic gia cc ngang cp LDP, dng TCP

Advertisement : To,thay i v xa cc nh xnhn cho cc FEC, dng TCP

Notification : cung cp thng tin trng thi, chnan v thng tin li, dng TCP

66

V d Router : chuyn tip gi


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Nguyn Xun Khnh 3

67

V d MPLS : Thng tin nh tuyn

68

V d MPLS : Gn nhn


35/40


Nguyn Xun Khnh 3

69

V d MPLS : Chuyn tip gi

70

Cc phng php phn phi nhn

Downstream unsolicited

Node downstream ch thng bo cc nhn c

dng cho cc prefixe/FEC c th i ti thng qua n.

Xem v d trc

Downstream on-demand

Node upstream yu cu mt nhn cho prefixe/FEC

i qua node downstream

Xem v d k


36/40


Nguyn Xun Khnh 3

71

V d ATM MPLS : Yu cu nhn

i cn mt nhn cho

1

3

0

1 0128.89

171.69

Ti cn mt nhn cho

In

labelOut

Iface

Address

Prefix

Out

label

In

labelOut

Iface

Address

Prefix

Out

label

In

I/F

In

labelOut

Iface

Address

Prefix

Out

label

In

I/F

Label Distribution

Protocol (LDP)(Downstream Allocation on Demand)

2

Ti cn mt nhn cho

Ti cn mt nhn cho

Ti cn mt khc nhn cho

Ti cn mt nhn cho

72

V d ATM MPLS : Yu cu nhn

ng nhn 4 cho ch

1

3

0

1 0128.89

171.69

Dng nhn 5 cho ch

Dng nhn 8 cho ch 128.89


Dng nhn 9 cho ch


In

labelOut

Iface

Address

Prefix

Out

label

In

labelOut

Iface

Address

Prefix

Out

labelIn

I/F

In

labelOut

Iface

Address

Prefix

Out

labelIn

I/F

2


37/40


Nguyn Xun Khnh 3

73

V d ATM MPLS : Chuyn tip gi

1

1

0

1 0128.89

171.69

In

labelOut

Iface

Address

Prefix

Out

label

In

labelOut

Iface

Address

Prefix

Out

labelIn

I/F

In

labelOut

Iface

Address

Prefix

Out

labelIn

I/F

128.89.25.4 Data

128.89.25.4 Data4

128.89.25.4 Data9

128.89.25.4 Data

Chuyn mch nhnchuyn tip da vo nhn

2

74

Nhn ra v iu khin hin tngLoop

Lp vng (loop) l hin tng lu thng i ngang quamng khng dt

Trong MPLS lp vng xy ra trong qu trnh thit lpLSP

LDP h tr 2 c ch pht hin v trnh lp vng :

- Time to Live (TTL)

- Path vectors


38/40


Nguyn Xun Khnh 3

75

TTL

Tng t nh trong mng chuyn tip IP, ch c 2 khcbit :

- Gi tr TTL c gi l hop count

- Hop count c tng qua mi ln i qua mt LSR

Trong cc bn tin thit lp LSP ca LDP (Label request,Label mapping) c vng TTL. Gi tr TTL c gia tng khi

i qua mt LSR, v nu TTL t n gi tr cc i c

cu hnh trc bi nh thit k phn mn MPLS/LDP hoc

nh khai thc mng th bn tin n s b lai b

76

Path Vectors

Tng t vi khi nim route recording trong internet Path vector c trong cc bn tin Label request, Label

mapping ca LDP. N cha danh sch cc ID ca cc

LSR m n i qua.

Khi mt LSR lan truyn bn tin c cha path vector n sb sung ID ca n vo danh sch.

Mt LSR nhn ra mt bn tin lp vng khi n thy ID can trong vng path vector ca bn tin ny


39/40


Nguyn Xun Khnh 3

77

V d v lp vng

78

Cc phng php phn phi nhnKhc- RSVP

S dng trong MPLS-TE (Traffic Engineering)

B xung giao thc bo hiu MPLS

Dng c ch iu khin chp nhn kt ni ca RSVP

to mt LSP vi bng thng yu cu.

Cc yu cu nhn c gi trong cc bn tin Path v s

rng buc nhn c thc hin thng qua cc bn tin

RESV

i tng Explicit-route xc nh con ng m cc bntin thit lp nn i qua

S dng RSVP c nhiu thun li


40/40


79

Cc phng php phn phi nhn

Khc- BGP

S dng trong MPLS VPN

Cn m rng a giao thc cho BGP.

Cc router phi l cc BGP ngang cp.

Thng tin nh x nhn c mang trong mt phn

ca NLRI (Network Layer Reacheability Information)

chuyen mạch_MPLS [Compatibility Mode]

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