腾科教育hcnp课件-mpls协议原理

前言本课程分析了传统IP在转发速率、Qos和流量工程方面的缺陷，介绍了MPLS转发的基本特点。Page1培训目标学完本课程后，您应该能：描述IP转发流程描述IP转发的缺点解释MPLS转发基本原理描述MPLS应用Page2MPLS概述MPLS基本原理

MPLS环路检测Page3MPLS概述传统IP转发MPLS

转发特点MPLS应用Page4传统IP转发SWASWBSWCSWD/24/24

v1

v1

/30

v2

v2/30

v3

v3/30/30/30DataPage5传统IP转发(SWA)SWA/24

v1

/30NetworkNexthop/24/32/30/32/30/30/24/30

DataPage6Page7传统IP转发(SWB)SWB

v1/30

v2

/30NetworkNexthop/24/30/32/30/32/30/24Page8传统IP转发(SWC)SWC

v2/30

v3

/30NetworkNexthop/24/30/30/32/300/320/240传统IP转发(SWD)SWD

v3/30/24Page9NetworkNexthop/24/30/30/300/32/24/32/30传统IP转发在流量工程方面的缺陷SWASWBSWDSWESWCNetwork

ASWFSWGSWHGEPage10GEFEFEFE100%

Traffic100%

TrafficNetwork

CNetwork

BMPLS转发SWBSWCSWD/24

v2

v2

/30

v3

v3

/30/32SWA

v1

v1/30DataIPHeaderMPLS1024DataIPHeaderMPLS

HeaderDataIP

Header1029DataIPHeader1039DataIPHeaderDataIPHeader/24Page11MPLS应用ABABMPLSPEPEPEPEPPPPCECECECECECECECEABABPage12MPLS

TE应用SWASWBSWDSWENetwork

BPage13Network

CSWCNetwork

ASWFSWGSWHGEGEFEFE70%

TrafficFE70%

Traffic30%

Traffic30%

TrafficMPLSQos应用Network

ANetwork

BPEPEPPCECEMPLSClassify

TrafficMap

toDSCPMap

into

labelMap

DSCP

toEXPPQ/CQ/CBQ

accordingto

EXPPage14Page15MPLS概述MPLS基本原理MPLS环路检测MPLS基本原理MPLS基本结构MPLS

格式MPLS转发流程传统IP转发Page161039DataIPHeader1029DataIPHeader1024DataIPHeaderMPLS网络模型SWASWBSWCSWDIP

NetworkLERIP

NetworkLERSWFSWGLSRSWEMPLSLSPDataIPHeaderDataIPHeaderLER

Label

Edge

RouterLSR

Label

Switch

RouterLSP

Label

Switch

PathPage17MPLS结构Routing

ProtocolLabel

DistributionProtocolLabel

Forwarding

Table控制平面交换路由信息IP

Forwarding

TableIP

Routing

Table数据平面交换发送带

报文发送IP报文接收带

报文接收IP报文Page18MPLS基本原理MPLS基本结构MPLS

格式MPLS转发流程传统IP转发Page19Page20帧模式MPLSFrameHeaderIP

HeaderPayloadFrameHeaderMPLSHeaderIP

HeaderPayload二层帧格式MPLS帧模式封装MPLS

HeaderMPLS头部总长度为4bytes(32bits)Label长度20bitsEXP（Experimental

Use）长度3bitsS（Bottom

of

Stack）长度1bitTTL长度8bitsLABELEXPSTTL03119

2022

23

24Page21MPLS嵌套FrameHeaderLabel

1Label

2Label

3IP

HeaderPayloadS=0

S=0S=1PID=MPLS-IPPID

标识二层头部后面的报文类型Ethernet

0x0800

IPv4

0x8847

MPLS

单播报文0x8848

MPLS多播报文PPP

0x8021

IPv4

0x8281

MPLS

单播报文0x8283MPLS多播报文S

标识是否是栈底嵌套应用MPLSMPLS

TEPage22MPLS基本原理MPLS基本结构MPLS

格式MPLS转发流程传统IP转发Page23MPLS转发－Ingress

LERSWBSWCSWD/24/24

v2

v2/30

v3

v3

/30/32SWA

v1

v1/30

DataMPLS1030DataIPHeader/30/30Page24MPLS转发－Ingress

LERFEC：Forwarding

Equivalence

Classes（转发等价类）NHLFE：Next

Hop

Label

Forwarding

Entry

（下一跳

转项）<SWA>displaympls

lsp

include

24

verboseLSP

Information:

LDP

LSPNo

:VrfIndex

:1Fec

:/24Nexthop

:In-Label

:NULLOut-Label

:1030In-Interface

:------Out-Interface

:Vlanif1LspIndex

:10249Token

:0x22005LsrType

:IngressOutgoing

token

:0x0Label

Operation

:PUSHMpls-Mtu

:1500TimeStamp

:822secPage25MPLS转发－Ingress

LER（SWA）FTN：FEC

to

NHLFE（到

HLFE）SWBSWCSWD/24/24

v1

v1

/30

v2

v2

/30

v3

v3

/30/32SWAMPLS/30/30FECNHLFENextHopOut

InterfaceLabelOperationOthersVlanif1Push……

Data1030DataIPHeaderPage26MPLS转发－LSR

（SWB）SWBSWCSWD/24/24

v2

v2

/30

v3

v3/30/32SWA

v1

v1/30MPLS1030DataIPHeader

Data1030DataIPHeader/30/30Page27MPLS转发－LSR

(SWB)ILMing

LabelMap<SWB>display

mpls

lsp

include

24

in-label

1030

verboseLSP

Information:

LDP

LSPPage28No

:1VrfIndex

:Fec

:/24Nexthop

:In-Label

:1030Out-Label

:1030In-Interface

:------Out-Interface

:Vlanif2LspIndex

:10256Token

:0x2200cLsrType

:TransitOutgoing

token

:0x0Label

Operation

:SWAPMpls-Mtu

:1500TimeStamp

:11100secMPLS转发－LSR

(SWC)InLabelNHLFENextHopOut

InterfaceLabelOperationOthers10300Vlanif3SWAP……SWBSWCSWD/24/24/30/30v1v2v2v3v3/30/32SWAv1MPLS1030DataIPHeaderData1030DataIPHeaderDataIPHeader1032/30/30Page29MPLS数据转发－LSR

（SWC）<SWC>display

mpls

lsp

include

24

in-label

1030

verboseLSP

Information:

LDP

LSPPage30No

:1VrfIndex

:Fec

:/24Nexthop

:0In-Label

:1030Out-Label

:1032In-Interface

:--Out-Interface

:Vlanif3LspIndex

:10268Token

:0x22015LsrType

:TransitOutgoing

token

:0x0Label

Operation

:SWAPMpls-Mtu

:1500TimeStamp

:40secMPLS转发－Egress

LER

（SWD）InLabelNHLFENextHopOut

InterfaceLabel

OperationOthers1032-POP……SWBSWCSWD/24/24

v2

v2

/30

v3

v3/30/32SWA

v1

v1/30MPLS1030

Data

Data1030

Data1030

Data103

Data/30

Data/30Page31MPLS转发－Egress

LER

（SWD）<SWD>display

mpls

lsp

include

24

in-label

1032

verboseLSP

Information:

LDP

LSPPage32No

:1VrfIndex

:Fec

:/24Nexthop

:In-Label

:1032Out-Label

:NULLIn-Interface

:--Out-Interface

:--LspIndex

:10258Token

:0x0LsrType

:EgressOutgoing

token

:0x0Label

Operation

:POPMpls-Mtu

:---TimeStamp

:924secTimeStamp

:40secMPLS概述MPLS基本原理MPLS环路检测Page33MPLS环路检测MPLS

TTL环路检测LDP环路检测Page34Page35MPLS环路检测IGP环路检测机制TTL环路检测帧模式的MPLS中使用TTL信元模式的MPLS中无TTLLDP环路检测机制距离向量法最大跳数法MPLS对TTL的处理/24/24

v1

v1

/30

v2

v2

/30

v3

v3

/30MPLS/3SWA2/32SWB/32SWC/32SWD10109108Label

TTLIPTTLIPTTL减1，并拷贝到Label

TTL7810IP

TTL不变，LabelTTL减1Label

TTL减1，拷贝回

IPTTL.Page36MPLS

TTL配置与实例分析MPLS/32SWA

v1

v1/30/32SWB

v2

v2

/30/32SWC

v3

v3/30/32SWDSWJSWK/30v3v3/30v1v1<SWJ>-h

11

Page37MPLS

TTL配置与实例分析<SWA>debug

mpls

packet<SWA>debug

ip

packet

acl

3000<SWA>terminal

monitor<SWA>terminal

debugging*0.86297391

SWA

IP/8/debug_case:Receiving,

interface

=

Serial3,

version

=

4,

headlen

=

20,

tos

=

0,pktlen

=

84,

pktid

=

2273,

offset

=

0,

ttl

=

11,

protocol

=

1,checksum

=

37572,

s

=

,

d

=

prompt:

Receiving

IP

packet

from

Serial3*0.86297391

SWA

IP/8/debug_case:Sending,

interface

=

Serial3,

version

=

4,

headlen

=

20,

tos

=

0,pktlen

=

84,

pktid

=

2273,

offset

=

0,

ttl

=

10,

protocol

=

1,checksum

=

37572,

s

=

,

d

=

prompt:

Sending

the

packet

by

lsp*0.86297391

SWA

MFW/8/MPLSF

CKET:PUSH

Label=1030,

EXP=0,

TTL=10Sending

to

V1,

PktLen=88,

Label(s)=1030,

EXP=0,

TTL=10Page38MPLS

TTL配置与实例分析<SWB>debug

mpls

packet<SWB>debug

ip

packet

acl

3000<SWB>terminal

monitor<SWB>terminal

debugging*0.189653734

SWB

MFW/8/MPLSF

CKET:Receiving

from

V1,

PktLen=88,

Label(s)=1030,

EXP=0,

TTL=10SWAP

Label=1029,

EXP=0,

TTL=9Sending

to

V2,

PktLen=88,

Label(s)=1029,

EXP=0,

TTL=9<SWC>debug

mpls

packet<SWC>debug

ip

packet

acl

3000<SWC>terminal

monitor<SWC>terminal

debugging*0.189533719

SWC

MFW/8/MPLSF

CKET:Receiving

from

V2,

PktLen=88,

Label(s)=1029,

EXP=0,

TTL=9SWAP

Label=3,

TTL=8Sending

to

V3,

Dest=,

Nexthop=0Page39MPLS

TTL配置与实例分析<SWD>debug

mpls

packet<SWD>debug

ip

packet

acl

3000<SWD>terminal

monitor<SWD>terminal

debugging*0.64991297

SWD

IP/8/debug_case:Receiving,

interface

=

Serial3,

version

=

4,

headlen

=

20,

tos

=

0,pktlen

=

84,

pktid

=

2273,

offset

=

0,

ttl

=

8,

protocol

=

1,checksum

=

38340,

s

=

,

d

=

prompt:

Receiving

IP

packet

from

Serial3*0.64991297

SWD

IP/8/debug_case:Sending,

interface

=

Serial1,

version

=

4,

headlen

=

20,

tos

=

0,pktlen

=

84,

pktid

=

2273,

offset

=

0,

ttl

=

7,

protocol

=

1,checksum

=

38596,

s

=

,

d

=

prompt:

Sending

the

packet

from

Serial3

at

Serial1<SWJ>tracert

Page40tracerouteto()

30

hops

max,40

bytes

packet1

31ms 32

ms 1

ms2

62ms94ms62ms3

94ms94ms94ms4

0

125

ms 125

ms 125

ms5

156

ms 156

ms 156

msMPLS对TTL的处理/24/24

v1

v1

/30

v2

v2

/30

v3

v3

/30MPLS/3SWA2/32SWB/32SWC/32SWD255102541010Label

TTLIPTTLIPTTL

减1，但不拷贝Label

TTL。LabelTTL

强制设为255925310IP

TTL

不变，Label

TTL

减1。Label

TTL

减1，去掉标签。Page41MPLS

TTL配置与实例分析MPLS/32SWA

v1

v1/30/32SWB

v2

v2

/30/32SWC

v3

v3/30/32SWDSWJSWK/30v3v3/30v1v1[SW]mpls[SW-mpls]undo

ttl

propagate

public<SWJ>-h

11

Page42MPLS

TTL配置与实例分析<SWA>debug

mpls

packet<SWA>debug

ip

packet

acl

3000<SWA>terminal

monitor<SWA>terminal

debugging*0.81886516

SWA

IP/8/debug_case:Receiving,

interface

=

Serial3,

version

=

4,

headlen

=

20,

tos

=

0,pktlen

=

84,

pktid

=

1318,

offset

=

0,

ttl

=

11,

protocol

=

1,checksum

=

38527,

s

=

,

d

=

prompt:

Receiving

IP

packet

from

Serial3*0.81886516

SWA

IP/8/debug_case:Sending,

interface

=

Serial3,

version

=

4,

headlen

=

20,

tos

=

0,pktlen

=

84,

pktid

=

1318,

offset

=

0,

ttl

=

10,

protocol

=

1,checksum

=

38527,

s

=

,

d

=

prompt:

Sending

the

packet

by

lsp*0.81886516

SWA

MFW/8/MPLSF

CKET:PUSH

Label=1030,

EXP=0,

TTL=255Sending

to

V1,

PktLen=88,

Label(s)=1030,

EXP=0,

TTL=255Page43MPLS

TTL配置与实例分析<SWD>debug

mpls

packet<SWD>debug

ip

packet

acl

3000<SWD>terminal

monitor<SWD>terminal

debugging*0.99910344

SWD

IP/8/debug_case:Receiving,

interface

=

Serial3,

version

=

4,

headlen

=

20,

tos

=

0,pktlen

=

84,

pktid

=

9625,

offset

=

0,

ttl

=

10,

protocol

=

1,checksum

=

30476,

s

=

,

d

=

prompt:

Receiving

IP

packet

from

Serial3*0.99910344

SWD

IP/8/debug_case:Sending,

interface

=

Serial1,

version

=

4,

headlen

=

20,

tos

=

0,pktlen

=

84,

pktid

=

9625,

offset

=

0,

ttl

=

9,

protocol

=

1,checksum

=

30732,

s

=

,

d

=

prompt:

Sending

the

packet

from

Serial3

at

Serial1Page44MPLS/32SWA

v1

v1/30/32SWB

v2

v2

/30/32SWC

v3

v3/30/32SWDSWK/30v3v3/30v1v1MPLS

TTL配置与实例分析SWJ<SWJ>tracert

traceroute

to ()

30

hops

max,40

bytes

packet1

31

ms 31

ms2

0

156

ms 94

ms32

ms125

ms3

125

ms 125

ms 125

msPage45MPLS/32SWA

v1

v1/30/32SWB

v2

v2

/30/32SWC

v3

v3/30/32SWDSWJSWK/30v3v3/30v1v1MPLS

TTL配置与实例分析1The traceroute

packetwith

TTL=1

is

dropped

bySwitchADiscardPage46

v1

v1

/30

v2

v2

/30

v3

v3/30MPLS/3SWA2/32SWB/32SWC/32SWDSWJSWK/30v3v3/30v1v1MPLS

TTL配置与实例分析2The traceroute

packet

withTTL=1

is

dropped

by

SwitchADiscard255125411Page47TTL和环路检测/24/24/30

v1

v1

/30v2MPLS/3SWA2/32SWBv2/32SWC

v3

v3/30/32SWD1010910Label

TTLIP

TTL7810710…….110Page48MPLS环路检测MPLS

TTL环路检测LDP环路检测Page49LDP路径向量法/24/24MPLS/32SWA

v1

v1/30/32SWB

v2

v2

/30/32SWC

v3

v3/30/32SWDLabel

Request(length

1

)()Label

Request(length

2)

)(,)Label

Request(length

3))(,,)Label

Request(length

2))(,)DiscardPage50LDP最大跳数法/24/24MPLS/32SWA

v1

v1/30/32SWB

v2

v2

/30/32SWC

v3

v3/30/32SWDLabel

Request(Count=1)Label

Request(Count=2)Label

Request(Count=3)Label

Request(Count=3)DiscardLabel

Request(Count=4)Label

Request(Count=5)Page51LDP环路检测基本配置[SWC-mpls-ldp]display

mpls

ldpLDPGlobal

InformationProtocol

Version :

V1Neighbor

Liveness

:600SecGraceful

Restart :

OffFT

Reconnect

Timer

:300SecMTU

Signaling :

OnRecovery

Timer

:300SecLDPInstance

InformationInstance

ID :

0-Instance

:LSR

IDPath

Vector

Limit:

:

32Instance

StatusHop

Count

LimitLoop