MSR系列路由器MPLS静态LSP的典型配置

MSR路由器MPLS 静态LSP的典型配置

 

一、组网需求

1. Router 1、Router2、Router3均支持MPLS；

2. Router1和Router3之间建立静态LSP，使得11.1.1.1和33.3.3.3两个网段的互访能够通过 MPLS进行传输；

3. 检测Router1和Router3之间静态LSP的可达性。

设备清单：MSR路由器3台

 

二、组网图

 

图一  MSR路由器MPLS建立静态LSP组网图

三、配置步骤

 

Router1配置：

[Router1]display current-configuration

#

version 5.20, Release 2318, Standard

#

sysname Router1

#

mpls lsr-id 1.1.1.1

#

interface LoopBack0

ip address 11.1.1.1 255.255.255.255

#

interface LoopBack1

ip address 1.1.1.1 255.255.255.255

#

//接口使能MPLS功能

interface GigabitEthernet0/0

port link-mode route

ip address 12.1.1.1 255.255.255.0

mpls

#

//配置掩码为32的路由条目

ip route-static 33.3.3.3 255.255.255.255 12.1.1.2

#

//配置为33.3.3.3/32分配标签，出标签为30

static-lsp ingress atoc destination 33.3.3.3 32 nexthop 12.1.1.2 out-label 30

 

static-lsp egress ctoa incoming-interface GigabitEthernet0/0 in-label 70

 

Router2配置：

<Router2>display current-configuration

#

version 5.20, Release 2105P31, Standard

#

sysname Router2

#

mpls lsr-id 2.2.2.2

#

mpls

#

interface LoopBack0

ip address 2.2.2.2 255.255.255.255

#

//接口G0/0使能MPLS功能

interface GigabitEthernet0/0

port link-mode route

ip address 12.1.1.2 255.255.255.0

mpls

#

//接口G0/1使能MPLS功能

interface GigabitEthernet0/1

port link-mode route

ip address 23.1.1.1 255.255.255.0

mpls

#

//配置静态LSP

static-lsp transit atoc incoming-interface GigabitEthernet0/0 in-label 30 nexthop 23.1.1.2 out-label 50

static-lsp transit ctoa incoming-interface GigabitEthernet0/1 in-label 40 nexthop 12.1.1.1 out-label 70

 

Router3配置：

[Router3]display current-configuration

#

version 5.20, Release 2311, Standard

#

sysname Router3

#

mpls lsr-id 3.3.3.3

#

interface LoopBack0

ip address 33.3.3.3 255.255.255.255

#

interface LoopBack1

ip address 3.3.3.3 255.255.255.255

#

//使能MPLS功能

interface GigabitEthernet0/1

port link-mode route

ip address 23.1.1.2 255.255.255.0

mpls

#

//配置24位的静态路由

ip route-static 11.1.1.0 255.255.255.0 23.1.1.1

#

//为11.1.1.0/24分配标签

static-lsp ingress ctoa destination 11.1.1.0 24 nexthop 23.1.1.1 out-label 40

static-lsp egress atoc incoming-interface GigabitEthernet0/1 in-label 50

 

四、测试过程

//显示为FEC静态分配的标签

[Router1]display mpls static-lsp

total statics-lsp : 2

Name FEC I/O Label I/O If State

atoc 33.3.3.3/32 NULL/30 -/GE0/0 Up

ctoa -/- 70/NULL GE0/0/- Up

 

//查看Router1的全局FIB表项，token值为3

[Router1]display fib

 

Destination/Mask Nexthop Flag OutInterface InnerLabel Token

33.3.3.3/32 12.1.1.2 USGH GE0/0 Null 3

 

//查看Router1的NHLFE表象，Token3对应动作为压入标签30

[Router1]display mpls nhlfe

 

Total NHLFE Entry: 1

 

Out-Interface Token Oper Nexthop Deep Stack

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

GE0/0 3 PUSH 12.1.1.2 1 30

 

//查看Router3的全局FIB表，token值为2

[Router3]display fib

 

Destination/Mask Nexthop Flag OutInterface InnerLabel Token

11.1.1.0/24 23.1.1.1 USG GE0/1 Null 2

 

//查看Router3的NHLFE表，token为2，对应动作为压入标签40

[Router3]display mpls nhlfe

 

Out-Interface Token Oper Nexthop Deep Stack

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

GE0/1 2 PUSH 23.1.1.1 1 40

 

//测试静态LSP的连通性

[Router1]ping lsp -a 11.1.1.1 ipv4 33.3.3.3 32

LSP Ping FEC: IPV4 PREFIX 33.3.3.3/32 : 100 data bytes, press CTRL_C to break

Reply from 23.1.1.2: bytes=100 Sequence=1 time = 2 ms

Reply from 23.1.1.2: bytes=100 Sequence=2 time = 2 ms

Reply from 23.1.1.2: bytes=100 Sequence=3 time = 2 ms

Reply from 23.1.1.2: bytes=100 Sequence=4 time = 1 ms

Reply from 23.1.1.2: bytes=100 Sequence=5 time = 1 ms

 

--- FEC: IPV4 PREFIX 33.3.3.3/32 ping statistics ---

5 packet(s) transmitted

5 packet(s) received

0.00% packet loss

round-trip min/avg/max = 1/1/2 ms

 

//本地是为33.3.3.3/32分的标签（查看static-lsp表可以看出），因此：

 

[Router1]ping lsp -a 11.1.1.1 ipv4 33.3.3.0 24

Error: Unknown lsp.

 

//在Router3上进行LSP可达性测试

[Router3]ping lsp -a 33.3.3.3 ipv4 11.1.1.0 24

LSP Ping FEC: IPV4 PREFIX 11.1.1.0/24 : 100 data bytes, press CTRL_C to break

Request time out

Request time out

Request time out

Request time out

 

[Router1]display ip routing-table

Routing Tables: Public

Destinations : 7 Routes : 7

 

Destination/Mask Proto Pre Cost NextHop Interface

 

11.1.1.1/32 Direct 0 0 127.0.0.1 InLoop0

33.3.3.3/32 Static 60 0 12.1.1.2 GE0/0

 

原因分析：

Router3本地封装好标签，经过中间网络的MPLS转发，到达Router1后，查找目的地址11.1.1.0，没有对应的路由表项，因此丢弃

而对端Router1 可以ping通，因为使用的是33.3.3.3/32，对端可以找到对应路由，而回包的时候，11.1.1.1可以匹配上11.1.1.0/24的路由，是可以打上标签的

 

Router3如果采用如下配置：

ip route-static 11.1.1.1 255.255.255.255 23.1.1.1

static-lsp ingress ctoa destination 11.1.1.0 24 nexthop 23.1.1.1 out-label 40

 

//上面路由和静态LSP不匹配（路由是32位，LSP是24位）则：

[Router3]display mpls static-lsp

total statics-lsp : 2

Name FEC I/O Label I/O If State

ctoa 11.1.1.0/24 NULL/40 -/GE0/1 Down

 

//Router3配置LSP和路由同为32的时候，LSP状态是Up的

ip route-static 11.1.1.1 255.255.255.255 23.1.1.1

static-lsp ingress ctoa destination 11.1.1.1 32 nexthop 23.1.1.1 out-label 40

 

[Router3]display mpls static-lsp

total statics-lsp : 2

Name FEC I/O Label I/O If State

ctoa 11.1.1.1/32 NULL/40 -/GE0/1 Up

 

[Router3]ping lsp -a 33.3.3.3 ipv4 11.1.1.1 32

LSP Ping FEC: IPV4 PREFIX 11.1.1.1/32 : 100 data bytes, press CTRL_C to break

Reply from 12.1.1.1: bytes=100 Sequence=1 time = 2 ms

Reply from 12.1.1.1: bytes=100 Sequence=2 time = 1 ms

Reply from 12.1.1.1: bytes=100 Sequence=3 time = 1 ms

Reply from 12.1.1.1: bytes=100 Sequence=4 time = 1 ms

Reply from 12.1.1.1: bytes=100 Sequence=5 time = 1 ms

修改上述组网：

将Router1的loopback0接口删除，在Router1的G0/1接口配置11.1.1.1/24，保证接口Up

[Router1]interface LoopBack 0

[Router1-LoopBack0]undo ip address

 

[Router1]interface GigabitEthernet 0/1

[Router1-GigabitEthernet0/1]ip address 11.1.1.1 24

 

[Router1]display ip routing-table

11.1.1.0/24 Direct 0 0 11.1.1.1 GE0/1

//再次在Router3进行LSP可达性测试

[Router3]ping lsp -a 33.3.3.3 ipv4 11.1.1.0 24

LSP Ping FEC: IPV4 PREFIX 11.1.1.0/24 : 100 data bytes, press CTRL_C to break

Reply from 12.1.1.1: bytes=100 Sequence=1 time = 2 ms

Reply from 12.1.1.1: bytes=100 Sequence=2 time = 2 ms

Reply from 12.1.1.1: bytes=100 Sequence=3 time = 2 ms

Reply from 12.1.1.1: bytes=100 Sequence=4 time = 1 ms

Reply from 12.1.1.1: bytes=100 Sequence=5 time = 1 ms

 

原因在于Router1本地存在11.1.1.0/24位的路由条目，可以找到对应的出口

五、配置关键点

1.手工指定静态LSP时，需要遵循以下原则：一条LSP，上游LSR出标签的值与下游LSR入标签的值相同；

2.LSP是一条单向路径，因此需要在数据传输的两个方向上分别配置一条静态LSP；

3.配置静态LSP时，只要求在Ingress节点上存在到达FEC目的地址的路由，Transit节点和Egresss节点上不需要存在到达FEC目的地址的路由，因此无需配置路由协议保证路由器之间路由的可达性，只需要在Ingress节点上配置到达FEC目的地址的静态路由即可，在P设备依靠标签交换进行转发。