Configuring Multi Area OSPF

configuring multiarea ospf

objective:

configure multiarea OSPF operation, interarea summarization, external route summarization and default routing.

topology:

configs:

SanJose3:

SanJose3#sh run
Building configuration…

Current configuration : 1729 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname SanJose3
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$ypAG$EbdmRvrpwemBIcVcmu75b/
!
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 192.168.1.3 255.255.255.0
duplex half
!
interface Serial1/0
ip address 192.168.224.1 255.255.255.252
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 192.168.1.0 0.0.0.255 area 0
network 192.168.3.0 0.0.0.255 area 0
network 192.168.224.0 0.0.0.3 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
login
!
!
end

SanJose3#

Singapore:

Singapore#sh run
Building configuration…

Current configuration : 1833 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 $1$AQ32$aPkEbUAsrR/1PajuOSNtq/
!
no aaa new-model
!
resource policy
!
ip cef
!
!
!
interface FastEthernet0/0
no ip address
shutdown
duplex half
!
interface Serial1/0
ip address 192.168.224.2 255.255.255.252
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
summary-address 192.148.240.0 255.255.240.0 (external route summarization)
redistribute static metric-type 1 (external route summarization using E1 type 5 LSA)
network 192.168.224.0 0.0.0.3 area 51
!
ip route 192.168.240.0 255.255.255.0 Null0
ip route 192.168.244.0 255.255.255.0 Null0
ip route 192.168.248.0 255.255.255.0 Null0
ip route 192.168.252.0 255.255.255.0 Null0
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
login
!
!
end

Singapore#

SanJose1:

SanJose1#sh run
Building configuration…

Current configuration : 1237 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 $1$ocFL$HKIOiot107PO6H3IDYjIV0
!
no aaa new-model
!
resource policy
!
ip cef
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface Loopback0
ip address 192.168.64.1 255.255.255.0
!
interface Loopback1
ip address 192.168.80.1 255.255.255.0
!
interface Loopback2
ip address 192.168.96.1 255.255.255.0
!
interface Loopback3
ip address 192.168.112.1 255.255.255.0
!
interface Loopback5
ip address 10.0.0.6 255.255.255.252
!
interface FastEthernet0/0
ip address 192.168.1.1 255.255.255.0
duplex half
!
router ospf 1
log-adjacency-changes
area 1 range 192.168.64.0 255.255.192.0 (interarea summarization)
network 192.168.1.0 0.0.0.255 area 0
network 192.168.64.0 0.0.63.255 area 1
default-information originate always (distribute default routing information)
!
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#

summary:

• Router SanJose1is an ABR and ASBR (do sh ip ospf)
• Router SanJose3 is an ABR (do sh ip ospf)
• Router Singapore is an ASBR (do sh ip ospf)
• Type 5 LSA used to redistribute external routes. E2 type 5 LSA doesn’t count internal OSPF AS metric. E1 type 5 LSA count internal OSPF AS metric. So, when there are more than one link to external network, use E1 type 5 LSA do redistribute static metric-type 1 on router configuration mode.
• To distribute default routing information for other OSPF area to a specific router, do default-information originate always on that router. This will distribute Gateway of last resort to other routers to this specific router. PS: this router must be the only way out for other routers to the internet.

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Possibly related posts: (automatically generated)

• Configuring OSPF Virtual Link
• Configuring OSPF Stub and Totally Stub Area
• MPLS Traffic Engineering using Cisco IOS