Configuring OSPF Virtual Link

Configuring OSPF Virtual Link

Bài 1 : Configuring OSPF Virtual Link

Mục đích : cấu hình để cho một vùng không có liên lạc với backbone có thể liên lạc được Cấu hình :

+ Diagram:

Click this bar to view the small image

+ Chi tiết :

SanJose1#sh run

Building configuration…

Current configuration : 1015 bytes

!

version 12.4

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname SanJose1

!

boot-start-marker

boot-end-marker

!

enable secret 5 $1$bP5E$pamhnCUi0AcSl/F9Rej651

!

no aaa new-model

!

resource policy

!

ip cef

!

interface Loopback0

ip address 192.168.1.3 255.255.255.0

!

interface Loopback1

ip address 192.168.0.3 255.255.255.0

!

interface FastEthernet0/0

ip address 192.168.224.1 255.255.255.0 duplex half

!

router ospf 1

log-adjacency-changes

network 192.168.0.0 0.0.0.255 area 0 network 192.168.1.0 0.0.0.255 area 0 network 192.168.224.0 0.0.0.255 area 51

!

no ip http server

no ip http secure-server

!

logging alarm informational

!

control-plane

!

gatekeeper

shutdown

!

!

line con 0

exec-timeout 0 0

password cisco

logging synchronous

login

stopbits 1

line aux 0

stopbits 1

line vty 0 4

exec-timeout 0 0

password cisco

logging synchronous

login

!

!

end

SanJose1#

Singapore#sh run

Building configuration…

Current configuration : 1790 bytes

!

version 12.4

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname Singapore

!

boot-start-marker

boot-end-marker

!

enable secret 5 $1$bPdv$hcFIbsP8L4rzFyuNrFoqE0

!

no aaa new-model

!

resource policy

!

ip cef

!

interface Loopback0

ip address 192.168.3.1 255.255.255.0

!

interface FastEthernet0/0

ip address 192.168.224.2 255.255.255.0

duplex half

!

interface Serial1/0

ip address 192.168.240.1 255.255.255.252

serial restart-delay 0

no dce-terminal-timing-enable

!

interface Serial1/1

no ip address

shutdown

serial restart-delay 0

no dce-terminal-timing-enable

!

interface Serial1/2

no ip address

shutdown

serial restart-delay 0

no dce-terminal-timing-enable

!

interface Serial1/3

no ip address

shutdown

serial restart-delay 0

no dce-terminal-timing-enable

!

interface Serial1/4

no ip address

shutdown

serial restart-delay 0

no dce-terminal-timing-enable

!

interface Serial1/5

no ip address

shutdown

serial restart-delay 0

no dce-terminal-timing-enable

!

interface Serial1/6

no ip address

shutdown

serial restart-delay 0

no dce-terminal-timing-enable

!

interface Serial1/7

no ip address

shutdown

serial restart-delay 0

no dce-terminal-timing-enable

!

router ospf 1

log-adjacency-changes

network 192.168.3.0 0.0.0.255 area 51 network 192.168.224.0 0.0.0.255 area 51 network 192.168.240.0 0.0.0.3 area 3

!

no ip http server

no ip http secure-server

!

logging alarm informational

!

control-plane

!

gatekeeper

shutdown

!

!

line con 0

exec-timeout 0 0

password cisco

logging synchronous

login

stopbits 1

line aux 0

stopbits 1

line vty 0 4

exec-timeout 0 0

password cisco

logging synchronous

login

!

!

end

Singapore#

Auckland#sh run

Building configuration…

Current configuration : 1711 bytes

!

version 12.4

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname Auckland

!

boot-start-marker

boot-end-marker

!

enable secret 5 $1$W3Ux$X4cR/1jc27f9IbV5b.Qgn0

!

no aaa new-model

!

resource policy

!

ip cef

!

interface Loopback0

ip address 192.168.252.1 255.255.255.0

!

interface FastEthernet0/0

ip address 192.168.248.1 255.255.255.0

duplex half

!

interface Serial1/0

ip address 192.168.240.2 255.255.255.252

serial restart-delay 0

no dce-terminal-timing-enable

!

interface Serial1/1

no ip address

shutdown

serial restart-delay 0

no dce-terminal-timing-enable

!

interface Serial1/2

no ip address

shutdown

serial restart-delay 0

no dce-terminal-timing-enable

!

interface Serial1/3

no ip address

shutdown

serial restart-delay 0

no dce-terminal-timing-enable

!

interface Serial1/4

no ip address

shutdown

serial restart-delay 0

no dce-terminal-timing-enable

!

interface Serial1/5

no ip address

shutdown

serial restart-delay 0

no dce-terminal-timing-enable

!

interface Serial1/6

no ip address

shutdown

serial restart-delay 0

no dce-terminal-timing-enable

!

interface Serial1/7

no ip address

shutdown

serial restart-delay 0

no dce-terminal-timing-enable

!

router ospf 1

log-adjacency-changes

network 192.168.240.0 0.0.0.3 area 3

!

no ip http server

no ip http secure-server

!

!

!

logging alarm informational

!

control-plane

!

gatekeeper

shutdown

!

!

line con 0

exec-timeout 0 0

password cisco

logging synchronous

login

stopbits 1

line aux 0

stopbits 1

line vty 0 4

exec-timeout 0 0

password cisco

logging synchronous

login

!

!

end

Auckland#

Auckland#sh ip route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user

static route

o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

192.168.240.0/30 is subnetted, 1 subnets

C 192.168.240.0 is directly connected, Serial1/0

C 192.168.252.0/24 is directly connected, Loopback0

Auckland#

Ta nhận thấy rằng không có route nào được được học bởi OSPF được phân phối vào router Auckland

Notes : Bạn nên nhớ rằng, mặc dù area 51 và 3 là thân mật với nhau nhưng để ospf route

được updates thì inter area traffic phải được vận chuyển thông đến vùng backbone

Router Singapore là một ABR của vùng 3 , router SanJose1 là ABR của vùng 0 (backbone) Vì vậy , để hoàn thành mục đích : ospf route được update vào area 3 thì ta cần phải cấu hình "virtual link" trên Singapore và SanJose1 thông qua area 51 như một "vùng trung chuyển" (transit area) Code:

SanJose1:

!

router ospf 1

log-adjacency-changes

area 51 virtual-link 192.168.3.1 (Đây là router’s RID của Singapore)

network 192.168.0.0 0.0.0.255 area 0

network 192.168.1.0 0.0.0.255 area 0

network 192.168.224.0 0.0.0.255 area 51

!

Code:

Singapore:

!

router ospf 1

log-adjacency-changes

area 51 virtual-link 192.168.1.3

network 192.168.3.0 0.0.0.255 area 51

network 192.168.224.0 0.0.0.255 area 51

network 192.168.240.0 0.0.0.3 area 3

Kết quả :

Auckland#sh ip route

Codes: C - connected, S - static, R

D - EIGRP, EX - EIGRP external, O

N1 - OSPF NSSA external type 1, N2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1

ia - IS-IS inter area, * - candidate default, U

o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

O IA 192.168.224.0/24 [110/65] via 19

192.168.240.0/30 is subnetted, 1 subnets

C 192.168.240.0 is directly connected, Serial1/0

192.168.0.0/32 is subnetted, 1 subnets

O IA 192.168.0.3 [110/66] via 192.168.240.1, 00:00:01, Serial1/0

192.168.1.0/32 is subnetted, 1 subnets

O IA 192.168.1.3 [110/66] via 192.168.240.1, 00:00:01, Serial1/0

C 192.168.252.0/24 is directly connected, Loopback0

192.168.3.0/32 is subnetted, 1 subnets

O IA 192.168.3.1 [110/65] via 192.168.240.1, 00

Ngoài ra để xem "virtual link" bạ

Code:

#sh ip ospf virtual-links

Tóm lại :

== virtual links phải được cấu h

vùng trung chuyển (transit area)

== inter area traffic phài được chuy

192.168.1.3 (Đây là router’s RID của Sanjose1)

network 192.168.3.0 0.0.0.255 area 51

network 192.168.224.0 0.0.0.255 area 51

network 192.168.240.0 0.0.0.3 area 3

static, R - RIP, M - mobile, B - BGP EIGRP external, O - OSPF, IA - OSPF inter area OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

OSPF external type 2

IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

candidate default, U - per-user static route periodic downloaded static route

192.168.224.0/24 [110/65] via 192.168.240.1, 00 32, Serial1/0

192.168.240.0/30 is subnetted, 1 subnets

C 192.168.240.0 is directly connected, Serial1/0

192.168.0.0/32 is subnetted, 1 subnets

92.168.0.3 [110/66] via 192.168.240.1, 00:00:01, Serial1/0

192.168.1.0/32 is subnetted, 1 subnets

192.168.1.3 [110/66] via 192.168.240.1, 00:00:01, Serial1/0

C 192.168.252.0/24 is directly connected, Loopback0

192.168.3.0/32 is subnetted, 1 subnets

192.168.3.1 [110/65] via 192.168.240.1, 00 32, Serial1/0

xem "virtual link" bạn dùng thêm lệnh :

ấu hình trên cả 2 con router ngoài cùng (edge router) trong

n (transit area)

ợc chuyển đến vùng backbone

a Sanjose1)

ài cùng (edge router) trong