Single-Area OSPF Huawei

Bu bölümde tek bir alan için OSPF konfigurasyonu yapacağız, Router-Id belirlemeyi, hello ve dead sürelerini belirlemeyi, default-route’u OSPF de anons etmeyi ve DR ve BDR seçimini yaptırmayı göreceğiz.

1. OSPF routing protokolü için ortam hazırlayalım
   Lab konfigürasyonu için temel sistem ve ip address yapılandırmasını kuralım.
   system-view
   Enter system view, return user view with Ctrl+Z.
   [Huawei]sysname Router1
   [Router1]interface GigabitEthernet 0/0/1
   [Router1-GigabitEthernet0/0/1]ip address 10.0.12.1 24
   [Router1-GigabitEthernet0/0/1]quit
   [Router1]interface GigabitEthernet 0/0/0
   [Router1-GigabitEthernet0/0/0]ip address 10.0.13.1 24
   [Router1-GigabitEthernet0/0/0]quit
   [Router1]interface LoopBack 0
   [Router1-LoopBack0]ip address 10.0.1.1 24
   system-view
   Enter system view, return user view with Ctrl+Z.
   [Huawei]sysname Router2
   [Router2]interface GigabitEthernet 0/0/1
   [Router2-GigabitEthernet0/0/1]ip address 10.0.12.2 24
   [Router2-GigabitEthernet0/0/1]quit
   [Router2]interface LoopBack 0
   [Router2-LoopBack0]ip address 10.0.2.2 24
   system-view
   Enter system view, return user view with Ctrl+Z.
   [Huawei]sysname Router3
   [Router3]interface GigabitEthernet 0/0/0
   [Router3-GigabitEthernet0/0/0]ip address 10.0.13.3 24
   [Router3-GigabitEthernet0/0/0]quit
   [Router3]interface LoopBack 0
   [Router3-LoopBack0]ip address 10.0.3.3 24
   [Router3-LoopBack0]quit
   [Router3]interface LoopBack 2
   [Router3-LoopBack2]ip address 172.16.0.1 24
2. OSPF konfigürasyonu oluşturalım.
   Router ID yi 10.0.1.1 (Manuel olarak da loopback olmadan router-id girilebilir. Kolaylık için loopback’ipsi ile aynı girdik)olarak verelim. OSPF process 1 (default process)’i kullanalım, network ağlarınıda spesific olarak 10.0.1.0/24, 10.0.13.0/24 ve 10.0.12.0/24 networklerinde area0 ’ın bir parçası olarak belirtelim.
   [Router1]ospf 1 router-id 10.0.1.1
   [Router1-ospf-1]area 0
   [Router1-ospf-1-area-0.0.0.0]network 10.0.1.0 0.0.0.255
   [Router1-ospf-1-area-0.0.0.0]network 10.0.13.0 0.0.0.255
   [Router1-ospf-1-area-0.0.0.0]network 10.0.12.0 0.0.0.255
   Farklı process ID’leri farklı link-state veritabanları oluşturur, bundan dolayı bütün routerların aynı OSPF process ID’sine sahip olmasına dikkat edin. Wildcard mask’i network komutunda spesifik olarak o network için girilmelidir.

Router2’de manuel olarak 10.0.2.2 ‘yi router-id olarak konfigure edelim. OSPF process-id’miz 1 ve anons ettiğimiz network segmentleri 10.0.12.0/24 ve 10.0.2.0/24 olarak Area0 içinde yer alsın.
[Router2 ]id 10.0.2.2
[Router2]area 0
[Router2-ospf-1-area-0.0.0.0]network 10.0.2.0 0.0.0.255
[Router2-ospf-1-area-0.0.0.0]network 10.0.12.0 0.0.0.255
Manuel olarak 10.0.3.3 ‘yi router-id olarak konfigure edelim. OSPF process-id’miz 1 ve anons ettiğimiz network segmentleri 10.0.3.0/24 ve 10.0.13.0/24 olarak Area0 içinde yer alsın.
[R3id 10.0.3.3
[Router3-ospf-1]area 0
[Router3-ospf-1-area-0.0.0.0]network 10.0.3.0 0.0.0.255
[Router3-ospf-1-area-0.0.0.0]network 10.0.13.0 0.0.0.255

1. OSPF konfigürasyonunu kontrol edelim.
   OSPF route eşleşmesi tamamlandıktan sonra , Router1 ,Router2 ve Router3’ün routing tablosuna bakalım.
   display ip routing-table
   Route Flags: R – relay, D – download to fib
   —————————————————————————
   Routing Tables: Public
   Destinations : 10 Routes : 10
   Destination/Mask Proto Pre Cost Flags NextHop Interface
   10.0.1.0/24 Direct 0 0 D 10.0.1.1 LoopBack0
   10.0.1.1/32 Direct 0 0 D 127.0.0.1 LoopBack0
   10.0.2.2/32 OSPF 10 1 D 10.0.12.2 GigabitEthernet0/0/1
   10.0.3.3/32 OSPF 10 1 D 10.0.13.3 GigabitEthernet0/0/0
   10.0.12.0/24 Direct 0 0 D 10.0.12.1 GigabitEthernet0/0/1
   10.0.12.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1
   10.0.13.0/24 Direct 0 0 D 10.0.13.1 GigabitEthernet0/0/0
   10.0.13.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0
   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
   display ip routing-table
   Route Flags: R – relay, D – download to fib
   ——————————————————————————
   Routing Tables: Public
   Destinations : 9 Routes : 9
   Destination/Mask Proto Pre Cost Flags NextHop Interface
   10.0.1.1/32 OSPF 10 1 D 10.0.12.1 GigabitEthernet0/0/1
   10.0.2.0/24 Direct 0 0 D 10.0.2.2 LoopBack0
   10.0.2.2/32 Direct 0 0 D 127.0.0.1 LoopBack0
   10.0.3.3/32 OSPF 10 2 D 10.0.12.1 GigabitEthernet0/0/1
   10.0.12.0/24 Direct 0 0 D 10.0.12.2 GigabitEthernet0/0/1
   10.0.12.2/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1
   10.0.13.0/24 OSPF 10 2 D 10.0.12.1 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
   display ip routing-table
   Route Flags: R – relay, D – download to fib
   ——————————————————————————
   Routing Tables: Public
   Destinations : 11 Routes : 11
   Destination/Mask Proto Pre Cost Flags NextHop Interface
   10.0.1.1/32 OSPF 10 1 D 10.0.13.1 GigabitEthernet0/0/
   10.0.2.2/32 OSPF 10 2 D 10.0.13.1 GigabitEthernet0/0/0
   10.0.3.0/24 Direct 0 0 D 10.0.3.3 LoopBack0
   10.0.3.3/32 Direct 0 0 D 127.0.0.1 LoopBack0
   10.0.12.0/24 OSPF 10 2 D 10.0.13.1 GigabitEthernet0/0/0
   10.0.13.0/24 Direct 0 0 D 10.0.13.3 GigabitEthernet0/0/0
   10.0.13.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0
   27.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0
   127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0
   172.16.0.0/24 Direct 0 0 D 172.16.0.1 LoopBack2
   172.16.0.1/32 Direct 0 0 D 127.0.0.1 LoopBack2
   Router1 ve Router2 arasında 10.0.1.1’e, de Router2 ve Router3 arasında 10.0.3.3’e pingatarak networkü kontrol edelin.
   ping 10.0.1.1
   PING 10.0.1.1: 56 data bytes, press CTRL_C to break
   Reply from 10.0.1.1: bytes=56 Sequence=1 ttl=255 time=30 ms
   Reply from 10.0.1.1: bytes=56 Sequence=2 ttl=255 time=60 ms
   Reply from 10.0.1.1: bytes=56 Sequence=3 ttl=255 time=40 ms
   Reply from 10.0.1.1: bytes=56 Sequence=4 ttl=255 time=30 ms
   Reply from 10.0.1.1: bytes=56 Sequence=5 ttl=255 time=30 ms
   — 10.0.1.1 ping statistics —
   5 packet(s) transmitted
   5 packet(s) received
   0.00% packet loss
   round-trip min/avg/max = 30/38/60 ms
   ping 10.0.3.3
   PING 10.0.3.3: 56 data bytes, press CTRL_C to break
   Reply from 10.0.3.3: bytes=56 Sequence=1 ttl=254 time=60 ms
   Reply from 10.0.3.3: bytes=56 Sequence=2 ttl=254 time=80 ms
   Reply from 10.0.3.3: bytes=56 Sequence=3 ttl=254 time=30 ms
   Reply from 10.0.3.3: bytes=56 Sequence=4 ttl=254 time=80 ms
   Reply from 10.0.3.3: bytes=56 Sequence=5 ttl=254 time=80 ms
   — 10.0.3.3 ping statistics —
   5 packet(s) transmitted
   5 packet(s) received
   0.00% packet loss
   round-trip min/avg/max = 30/66/80 ms
   OSPF komşuluk durumuna display ospf peer komutuyla bakabiliriz.
   display ospf peer
   OSPF Process 1 with Router ID 10.0.1.1
   Neighbors
   Area 0.0.0.0 interface 10.0.12.1(GigabitEthernet0/0/1)’s neighbors
   Router ID: 10.0.2.2 Address: 10.0.12.2
   State: Full Mode:Nbr is Master Priority: 1
   DR: 10.0.12.1 BDR: 10.0.12.2 MTU: 0
   Dead timer due in 35 sec
   Retrans timer interval: 5
   Neighbor is up for 00:06:10
   Authentication Sequence: [ 0 ]
   Neighbors
   Area 0.0.0.0 interface 10.0.13.1(GigabitEthernet0/0/0)’s neighbors
   Router ID: 10.0.3.3 Address: 10.0.13.3
   State: Full Mode:Nbr is Master Priority: 1
   DR: 10.0.13.1 BDR: 10.0.13.3 MTU: 0
   Dead timer due in 39 sec
   Retrans timer interval: 5
   Neighbor is up for 00:03:58
   Authentication Sequence: [ 0 ]
   Display ospf peer komutuyla ospf komşuluklarını detaylı olarak inceleyebiliriz. Örnekteki ekran çıktısına bakarak Router1’in DR’ını 10.0.13.1 olarak belirlemiş. DR seçiminde sonsuz bir öncelik yoktur, yani DR durumu Router3’den Router1’e geçmeyecektir, geçmesi için OSPF process’i resetlenmelidir.
   Display ospf peer brief komutu ile ospf komuşularının daha küçük bir çıktısını verir.
   display ospf peer brief
   OSPF Process 1 with Router ID 10.0.1.1
   Peer Statistic Information
   ————————————————————————–
   Area Id Interface Neighbor id State
   0.0.0.0 GigabitEthernet0/0/1 10.0.2.2 Full
   0.0.0.0 GigabitEthernet0/0/0 10.0.3.3 Full
   ————————————————————————–
   display ospf peer brief
   OSPF Process 1 with Router ID 10.0.2.2
   Peer Statistic Information
   ————————————————————————–
   Area Id Interface Neighbor id State
   0.0.0.0 GigabitEthernet0/0/1 10.0.1.1 Full
   ————————————————————————–
   display ospf peer brief
   OSPF Process 1 with Router ID 10.0.3.3
   Peer Statistic Information
   ————————————————————————–
   Area Id Interface Neighbor id State
   0.0.0.0 GigabitEthernet0/0/0 10.0.1.1 Full
   ————————————————————————–
   Ospf hello interval ve dead interval aralıklarını(sürelerini) değiştirelim.
   Display ospf interface GigabitEthernet 0/0/0 komutu ile Router1 üzerinde default hello interval ve dead interval bilgilerini görüntüleyelim.
   display ospf interface GigabitEthernet 0/0/0
   OSPF Process 1 with Router ID 10.0.1.1
   Interfaces
   Interface: 10.0.13.1 (GigabitEthernet0/0/0)
   Cost: 1 State: DR Type: Broadcast MTU: 1500
   Priority: 1
   Designated Router: 10.0.13.1
   Backup Designated Router: 10.0.13.3
   Timers: Hello 10 , Dead 40 , Poll 120 , Retransmit 5 , Transmit Delay 1
   Ospf’in hello ve dead interval’ini degiştirmek için ospf timer komutunu kullanırız.Router1 ‘in hello interval 15 ,dead interval 60 olarak değiştirelim.
   [Router1]interface GigabitEthernet 0/0/0
   [Router1-GigabitEthernet0/0/0]ospf timer hello 15
   [Router1-GigabitEthernet0/0/0]ospf timer dead 60
   Oct 28 2014 15:56:17-08:00 Router1 %%01OSPF/3/NBR_DOWN_REASON(l)[1]:Neighbor state lea
   ves full or changed to Down. (ProcessId=1, NeighborRouterId=10.0.3.3, NeighborAreaId=0,
   NeighborInterface=GigabitEthernet0/0/0,NeighborDownImmediate reason=Neighb
   or Down Due to Inactivity, NeighborDownPrimeReason=Interface Parameter Mismatch,
   NeighborChangeTime=2014-10-28 15:56:17-08:00)
   display ospf interface GigabitEthernet 0/0/0
   OSPF Process 1 with Router ID 10.0.1.1
   Interfaces
   Interface: 10.0.13.1 (GigabitEthernet0/0/0)
   Cost: 1 State: DR Type: Broadcast MTU: 1500
   Priority: 1
   Designated Router: 10.0.13.1
   Backup Designated Router: 0.0.0.0
   Timers: Hello 15 , Dead 60 , Poll 120 , Retransmit 5 , Transmit Delay 1
   Router1 üzerinde ospf komşuluk durumunu kontrol edelim.
   display ospf peer brief
   OSPF Process 1 with Router ID 10.0.1.1
   Peer Statistic Information
   ————————————————————————–
   Area Id Interface Neighbor id State
   0.0.0.0 GigabitEthernet0/0/1 10.0.2.2 Full
   ————————————————————————–
   Yukarıdaki ekran çıktısında , Router1’in sadece tek bir komşusunun, Router2 olduğunu göstermektedir.
   OSPF hello interval ve dead interval değerleri Router1 ve Router3 üzerinde farklı, bundan dolayı Router1 ve Router3 OSPF komşuluğu kuramamaktadır.
   Ospf timer komutu ile Router3 üzerinde GE0/0/0 içinde Hello 15, Dead 60 olarak değiştirelim.
   [Router3]interface GigabitEthernet 0/0/0
   [Router3-GigabitEthernet0/0/0]ospf timer hello 15
   [Router3-GigabitEthernet0/0/0]ospf timer dead 60
   Oct 28 2014 16:02:55-08:00 Router3 %%01OSPF/4/NBR_CHANGE_E(l)[4]:Neighbor changes event:
   neighbor status changed. (ProcessId=1, NeighborAddress=10.0.13.1, NeighborEvent=Lo
   adingDone, NeighborPreviousState=Loading, NeighborCurrentState=Full)
   display ospf interface GigabitEthernet 0/0/0
   OSPF Process 1 with Router ID 10.0.3.3
   Interfaces
   Interface: 10.0.13.3 (GigabitEthernet0/0/0)
   Cost: 1 State: DR Type: Broadcast MTU: 1500
   Priority: 1
   Designated Router: 10.0.13.3
   Backup Designated Router: 10.0.13.1
   Timers: Hello 15 , Dead 60 , Poll 120 , Retransmit 5 , Transmit Delay 1
   Router1 üzerinde ospf komşuluk durumunu tekrar kontrol edelim.
   display ospf peer brief
   OSPF Process 1 with Router ID 10.0.1.1
   Peer Statistic Information
   ————————————————————————-
   Area Id Interface Neighbor id State
   0.0.0.0 GigabitEthernet0/0/1 10.0.2.2 Full
   0.0.0.0 GigabitEthernet0/0/0 10.0.3.3 Full
   ————————————————————————–
2. Default routeları OSPF’de anons etmek.
   Router3 üzerinde default-route’ları OSPF ile anons edelim.
   [Router3]ip route-static 0.0.0.0 0.0.0.0 LoopBack 2
   [R3]ospf 1[
   Router3-ospf-1]default-route-advertise
   Router1 ve Router2’nin routing tablolarına bakalım. Router3 tarafından anons edilen yolların ,Router1 ve Router2’nin routing tablosunda görüyoruz.
   display ip routing-table
   Route Flags: R – relay, D – download to fib
   —————————————————————————
   Routing Tables: Public
   Destinations : 11 Routes : 11
   Destination/Mask Proto Pre Cost Flags NextHop Interface
   0.0.0.0/0 O_ASE 150 1 D 10.0.13.3 GigabitEthernet0/0/0
   10.0.1.0/24 Direct 0 0 D 10.0.1.1 LoopBack0
   10.0.1.1/32 Direct 0 0 D 127.0.0.1 LoopBack0
   10.0.2.2/32 OSPF 10 1 D 10.0.12.2 GigabitEthernet0/0/1
   10.0.3.3/32 OSPF 10 1 D 10.0.13.3 GigabitEthernet0/0/0
   10.0.12.0/24 Direct 0 0 D 10.0.12.1 GigabitEthernet0/0/1
   10.0.12.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1
   10.0.13.0/24 Direct 0 0 D 10.0.13.1 GigabitEthernet0/0/0
   10.0.13.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0
   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
   display ip routing-table
   Route Flags: R – relay, D – download to fib
   —————————————————————————
   Routing Tables: Public
   Destinations : 10 Routes : 10
   Destination/Mask Proto Pre Cost Flags NextHop Interface
   0.0.0.0/0 O_ASE 150 1 D 10.0.12.1 GigabitEthernet0/0/1
   10.0.1.1/32 OSPF 10 1 D 10.0.12.1 GigabitEthernet0/0/1
   10.0.2.0/24 Direct 0 0 D 10.0.2.2 LoopBack0
   10.0.2.2/32 Direct 0 0 D 127.0.0.1 LoopBack0
   10.0.3.3/32 OSPF 10 2 D 10.0.12.1 GigabitEthernet0/0/1
   10.0.12.0/24 Direct 0 0 D 10.0.12.2 GigabitEthernet0/0/1
   10.0.12.2/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1
   10.0.13.0/24 OSPF 10 2 D 10.0.12.1 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
   display ip routing-table
   Route Flags: R – relay, D – download to fib
   ——————————————————————————
   Routing Tables: Public
   Destinations : 12 Routes : 12
   Destination/Mask Proto Pre Cost Flags NextHop Interface
   0.0.0.0/0 Static 60 0 D 172.16.0.1 LoopBack2
   10.0.1.1/32 OSPF 10 1 D 10.0.13.1 GigabitEthernet0/0/0
   10.0.2.2/32 OSPF 10 2 D 10.0.13.1 GigabitEthernet0/0/0
   10.0.3.0/24 Direct 0 0 D 10.0.3.3 LoopBack0
   10.0.3.3/32 Direct 0 0 D 127.0.0.1 LoopBack0
   10.0.12.0/24 OSPF 10 2 D 10.0.13.1 GigabitEthernet0/0/0
   10.0.13.0/24 Direct 0 0 D 10.0.13.3 GigabitEthernet0/0/0
   10.0.13.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0
   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
   172.16.0.0/24 Direct 0 0 D 172.16.0.1 LoopBack2
   172.16.0.1/32 Direct 0 0 D 127.0.0.1 LoopBack2
   Router2 üzerinde LoopBack2 (172.16.0.1) arasındaki bağlantıyı kontrol etmek için ping komutunu kullanalım.
   ping 172.16.0.1
   PING 172.16.0.1: 56 data bytes, press CTRL_C to break
   Reply from 172.16.0.1: bytes=56 Sequence=1 ttl=254 time=80 ms
   Reply from 172.16.0.1: bytes=56 Sequence=2 ttl=254 time=80 ms
   Reply from 172.16.0.1: bytes=56 Sequence=3 ttl=254 time=70 ms
   Reply from 172.16.0.1: bytes=56 Sequence=4 ttl=254 time=100 ms
   Reply from 172.16.0.1: bytes=56 Sequence=5 ttl=254 time=80 ms
   — 172.16.0.1 ping statistics —
   5 packet(s) transmitted
   5 packet(s) received
   0.00% packet loss
   round-trip min/avg/max = 70/82/100 ms
3. OSPF de DR,BDR seçimlerini kontrol edelim.
   Router1’de Router3’ün DR ve BDR bilgilerini görüntülemek için display ospf peer komutunu kullanalım.
   display ospf peer 10.0.3.3
   OSPF Process 1 with Router ID 10.0.1.1
   Neighbors
   Area 0.0.0.0 interface 10.0.13.1(GigabitEthernet0/0/0)’s neighbors
   Router ID: 10.0.3.3 Address: 10.0.13.3
   State: Full Mode:Nbr is Master Priority: 1
   DR: 10.0.13.3 BDR: 10.0.13.1 MTU: 0
   Dead timer due in 58 sec
   Retrans timer interval: 0
   Neighbor is up for 00:08:01
   Authentication Sequence: [ 0 ]
   Çıktı üzerinden Router3’ün DR ve Router1’in BDR olduğunu görüntülüyoruz. Çünkü Router3’
   router-id’si 10.0.3.3 Router1’in router-id’sinden daha iyidir(daha büyük). Router1 ve
   Router3 priority değerleri değiştirilmedi yani default olarak 1, bundan dolayı
   Seçimler router-id’leri üzerinden gerçekleşti.
   Ospf dr-priority komutu ile DR prioritylerini Router1 ve Router3’de değiştirelim.
   [Router1]interface GigabitEthernet 0/0/0
   [Router1-GigabitEthernet0/0/0]ospf dr-priority 200
   [Router3]interface GigabitEthernet 0/0/0
   [Router3-GigabitEthernet0/0/0]ospf dr-priority 100
   DR ve BDR seçimi non-preemption mod’dadır default da, yani herhangi bir şekilde DR yada BDR devreden çıkmadığı bir durumda tekrar seçilmeyecektir. Bundan dolayı tekrar seçim için OSPF komşuluk larını Router1 ve Router3 için resetlememiz gerekir.
   Bunu interfaceleri kapatıp açarak yapabiliriz.
   [Router3]interface GigabitEthernet 0/0/0
   [Router3-GigabitEthernet0/0/0]shutdown
   [Router1]interface GigabitEthernet 0/0/0
   [Router1-GigabitEthernet0/0/0]shutdown
   [Router1-GigabitEthernet0/0/0]undo shutdown
   [Router3-GigabitEthernet0/0/0]undo shutdown
   Router1’de Router3’ün DR ve BDR bilgilerini görüntülemek için display ospf peer komutunu kullanalım.
   [Router1]display ospf peer 10.0.3.3
   OSPF Process 1 with Router ID 10.0.1.1
   Neighbors
   Area 0.0.0.0 interface 10.0.13.1(GigabitEthernet0/0/0)’s neighbors
   Router ID: 10.0.3.3 Address: 10.0.13.3
   State: Full Mode:Nbr is Master Priority: 100
   DR: 10.0.13.1 BDR: 10.0.13.3 MTU: 0
   Dead timer due in 57 sec
   Retrans timer interval: 5
   Neighbor is up for 00:00:03
   Authentication Sequence: [ 0 ]
   Router1 priority değeri Router3’den yüksek oldugu için Router1 DR seçildi,Router3 ise BDR seçildi.
   Final….
   display current-configuration
   #
   sysname Router1
   #
   interface GigabitEthernet0/0/0
   ip address 10.0.13.1 255.255.255.0
   ospf dr-priority 200
   ospf timer hello 15
   #
   interface GigabitEthernet0/0/1
   ip address 10.0.12.1 255.255.255.0
   #
   interface LoopBack0
   ip address 10.0.1.1 255.255.255.0
   #
   ospf 1 router-id 10.0.1.1
   area 0.0.0.0
   network 10.0.1.0 0.0.0.255
   network 10.0.13.0 0.0.0.255
   network 10.0.12.0 0.0.0.255
   #
   user-interface con 0
   user-interface vty 0 4
   #
   Return
   display current-configuration
   #
   sysname Router2
   #
   interface GigabitEthernet0/0/1
   ip address 10.0.12.2 255.255.255.0
   #
   interface LoopBack0
   ip address 10.0.2.2 255.255.255.0
   #
   ospf 1 router-id 10.0.2.2
   area 0.0.0.0
   network 10.0.2.0 0.0.0.255
   network 10.0.12.0 0.0.0.255
   #
   user-interface con 0
   user-interface vty 0 4
   #
   Return
   display current-configuration
   #
   sysname Router3
   #
   interface GigabitEthernet0/0/0
   ip address 10.0.13.3 255.255.255.0
   ospf dr-priority 100
   ospf timer hello 15
   #
   interface LoopBack0
   ip address 10.0.3.3 255.255.255.0
   #
   interface LoopBack2
   ip address 172.16.0.1 255.255.255.0
   #
   ospf 1 router-id 10.0.3.3
   default-route-advertise
   area 0.0.0.0
   network 10.0.3.0 0.0.0.255
   network 10.0.13.0 0.0.0.255
   #
   ip route-static 0.0.0.0 0.0.0.0 LoopBack2
   #
   user-interface con 0
   user-interface vty 0 4
   #
   return