學習回顧——OSPF路由協定(0x30)-OSPF與BFD關聯配置示

如圖所示，AR1、AR2和AR3上運作OSPF實作網絡層互相可達。當AR1和AR2通過二層鍊路出現故障時，BFD能夠快速感覺通告OSPF，且切換到通過AR3進行通信。

1) 配置各路由器的IP位址并使能OSPF基本功能

【AR-1路由配置】

router id 1.1.1.1

#

interface GigabitEthernet0/0/0

ip address 1.1.1.1 255.255.255.0

#

interface GigabitEthernet0/0/1

ip address 2.2.2.1 255.255.255.0

#

interface LoopBack0

ip address 192.168.1.1 255.255.255.0

ospf network-type broadcast

#

ospf 1

area 0.0.0.1

network 1.1.1.0 0.0.0.255

network 2.2.2.0 0.0.0.255

network 192.168.1.0 0.0.0.255

#

【AR-2路由配置】

router id 2.2.2.2

#

interface GigabitEthernet0/0/0

ip address 1.1.1.2 255.255.255.0

#

interface GigabitEthernet0/0/1

ip address 3.3.3.1 255.255.255.0

#

interface LoopBack0

ip address 192.168.2.1 255.255.255.0

ospf network-type broadcast

#

ospf 1

area 0.0.0.1

network 1.1.1.0 0.0.0.255

network 3.3.3.0 0.0.0.255

network 192.168.2.0 0.0.0.255

【AR-3路由配置】

router id 3.3.3.3

interface GigabitEthernet0/0/0

ip address 2.2.2.2 255.255.255.0

#

interface GigabitEthernet0/0/1

ip address 3.3.3.2 255.255.255.0

#

ospf 1

area 0.0.0.1

network 2.2.2.0 0.0.0.255

network 3.3.3.0 0.0.0.255

#

2) 在AR1和AR2上分别配置OSPF與動态BFD會話關聯

【AR-1上配置】

[AR-1]bfd

[AR-1-bfd]q

[AR-1]interface g0/0/0

[AR-1-GigabitEthernet0/0/0]os

[AR-1-GigabitEthernet0/0/0]ospf bfd enable

[AR-1-GigabitEthernet0/0/0]ospf bfd min-tx-interval 500 min-rx-interval 500 detect-multiplier 4

【AR-2上配置】

[AR-2]bfd

[AR-2-bfd]q

[AR-2]interface g0/0/0

[AR-2-GigabitEthernet0/0/0]os

[AR-2-GigabitEthernet0/0/0]ospf bfd enable

[AR-2-GigabitEthernet0/0/0]ospf bfd min-tx-interval 500 min-rx-interval 500 detect-multiplier 4

3) 實驗結果驗證

【AR-1驗證結果】

[AR-1]dis ip routing-table

Route Flags: R - relay, D - download to fib

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

Routing Tables: Public

Destinations : 15 Routes : 16

Destination/Mask Proto Pre Cost Flags NextHop Interface

1.1.1.0/24 Direct 0 0 D 1.1.1.1 GigabitEthernet0/0/0

1.1.1.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0

1.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0

2.2.2.0/24 Direct 0 0 D 2.2.2.1 GigabitEthernet0/0/1

2.2.2.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1

2.2.2.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1

3.3.3.0/24 OSPF 10 2 D 1.1.1.2 GigabitEthernet0/0/0

OSPF 10 2 D 2.2.2.2 GigabitEthernet0/0/1

127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0 127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0

127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0

192.168.1.0/24 Direct 0 0 D 192.168.1.1LoopBack0

192.168.1.1/32 Direct 0 0 D 127.0.0.1 LoopBack0

192.168.1.255/32 Direct 0 0 D 127.0.0.1 LoopBack0

192.168.2.0/24 OSPF 10 1 D 1.1.1.2 GigabitEthernet0/0/0

255.255.255.255/32Direct 0 0 D 127.0.0.1 InLoopBack0

【AR-2驗證結果】

<AR-2>display ip routing-table

Route Flags: R - relay, D - download to fib

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

Routing Tables: Public

Destinations : 15 Routes : 16

Destination/Mask Proto Pre CostFlags NextHop Interface

1.1.1.0/24 Direct 0 0 D 1.1.1.2 GigabitEthernet0/0/0

1.1.1.2/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0

1.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0

2.2.2.0/24 OSPF 10 2 D 1.1.1.1 GigabitEthernet0/0/0

OSPF 10 2 D 3.3.3.2 GigabitEthernet0/0/1

3.3.3.0/24 Direct 0 0 D 3.3.3.1 GigabitEthernet0/0/1

3.3.3.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1

3.3.3.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1

127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0

127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0

127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0

192.168.1.0/24 OSPF 10 1 D 1.1.1.1 GigabitEthernet0/0/0

192.168.2.0/24 Direct 0 0 D 192.168.2.1LoopBack0

192.168.2.1/32 Direct 0 0 D 127.0.0.1 LoopBack0

192.168.2.255/32 Direct 0 0 D 127.0.0.1 LoopBack0

255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0

<AR-2>

【還可以在AR1或AR2上執行display ospf bfd session all】

<AR-1>display ospf bfd session all

OSPF Process 1 with Router ID 1.1.1.1

Area 0.0.0.1 interface 1.1.1.1(GigabitEthernet0/0/0)'s BFD Sessions

NeighborId:2.2.2.2 AreaId:0.0.0.1 Interface:GigabitEthernet0/0/0

BFDState:up rx :500 tx :500

Multiplier:0 BFD Local Dis:8192 LocalIpAdd:1.1.1.1

RemoteIpAdd:1.1.1.2 Diagnostic Info:No diagnostic information

<AR-1>

【驗證當AR1-AR2主鍊路發生故障時(假設AR2的G0/0/0接口Down了)，在分别在AR1和AR2上執行display ip routing-table】

<AR-1>dis ip routing-table

Route Flags: R - relay, D - download to fib

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

Routing Tables: Public

Destinations : 15 Routes : 15

Destination/Mask Proto Pre Cost Flags NextHop Interface

1.1.1.0/24 Direct 0 0 D 1.1.1.1 GigabitEthernet0/0/0

1.1.1.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0

1.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0

2.2.2.0/24 Direct 0 0 D 2.2.2.1 GigabitEthernet0/0/1

2.2.2.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1

2.2.2.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1

3.3.3.0/24 OSPF 10 2 D 2.2.2.2 GigabitEthernet0/0/1

127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0

127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0

127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0

192.168.1.0/24 Direct 0 0 D 192.168.1.1 LoopBack0

192.168.1.1/32 Direct 0 0 D 127.0.0.1 LoopBack0

192.168.1.255/32 Direct 0 0 D 127.0.0.1 LoopBack0

192.168.2.0/24 OSPF 10 2 D 2.2.2.2 GigabitEthernet0/0/1

255.255.255.255/32 Direct 0 0 127.0.0.1 InLoopBack0

<AR-1>

[AR-2-GigabitEthernet0/0/0]dis ip rou

Route Flags: R - relay, D - download to fib

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

Routing Tables: Public

Destinations : 13 Routes : 13

Destination/Mask Proto Pre Cost Flags NextHop Interface

1.1.1.0/24 OSPF 10 3 D 3.3.3.2 GigabitEthernet0/0/1

2.2.2.0/24 OSPF 10 2 D 3.3.3.2 GigabitEthernet0/0/1

3.3.3.0/24 Direct 0 0 D 3.3.3.1 GigabitEthernet0/0/1

3.3.3.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1

3.3.3.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1

127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0

127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0

127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0

192.168.1.0/24 OSPF 10 2 D 3.3.3.2 GigabitEthernet0/0/1

192.168.2.0/24 Direct 0 0 D 192.168.2.1 LoopBack0

192.168.2.1/32 Direct 0 0 D 127.0.0.1 LoopBack0

192.168.2.255/32 Direct 0 0 D 127.0.0.1 LoopBack0

255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0

[AR-2-GigabitEthernet0/0/0]