NBMA广播模式下配置OSPF

 

routerA：

interface Loopback0
 ip address 1.1.1.1 255.255.255.0
!
interface Serial0/1
 ip address 192.1.1.1 255.255.255.0
 encapsulation frame-relay
 ip ospf network broadcast
 serial restart-delay 0
!
router ospf 10
 log-adjacency-changes
 network 1.1.1.0 0.0.0.255 area 0
 network 192.1.1.0 0.0.0.255 area 0

routerB：

interface Loopback0
 ip address 2.2.2.2 255.255.255.0
!
interface Serial0/2
 ip address 192.1.1.2 255.255.255.0
 encapsulation frame-relay
 ip ospf network broadcast
 ip ospf priority 0
 serial restart-delay 0
 frame-relay map ip 192.1.1.1 201 broadcast
 frame-relay map ip 192.1.1.3 201 broadcast
!
router ospf 10
 log-adjacency-changes
 network 2.2.2.0 0.0.0.255 area 0
 network 192.1.1.0 0.0.0.255 area 0

routerC：

interface Loopback0
 ip address 3.3.3.3 255.255.255.0
!
interface Serial0/3
 ip address 192.1.1.3 255.255.255.0
 encapsulation frame-relay
 ip ospf network broadcast
 ip ospf priority 0
 serial restart-delay 0
 frame-relay map ip 192.1.1.1 301 broadcast
 frame-relay map ip 192.1.1.2 301 broadcast
!
router ospf 10
 log-adjacency-changes
 network 3.3.3.0 0.0.0.255 area 0
 network 192.1.1.0 0.0.0.255 area 0

看一下邻居关系

routerA#sh ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
2.2.2.2           0   FULL/DROTHER    00:00:38    192.1.1.2       Serial0/1
3.3.3.3           0   FULL/DROTHER    00:00:32    192.1.1.3       Serial0/1

routerB#sh ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
1.1.1.1           1   FULL/DR         00:00:32    192.1.1.1       Serial0/2

routerC#sh ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
1.1.1.1           1   FULL/DR         00:00:38    192.1.1.1       Serial0/3

路由表;

routerA#sh ip route
Gateway of last resort is not set

     1.0.0.0/24 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Loopback0
     2.0.0.0/32 is subnetted, 1 subnets
O       2.2.2.2 [110/65] via 192.1.1.2, 00:03:14, Serial0/1
     3.0.0.0/32 is subnetted, 1 subnets
O       3.3.3.3 [110/65] via 192.1.1.3, 00:03:14, Serial0/1
C    192.1.1.0/24 is directly connected, Serial0/1

routerB#sh ip route
Gateway of last resort is not set

     1.0.0.0/32 is subnetted, 1 subnets
O       1.1.1.1 [110/65] via 192.1.1.1, 00:03:22, Serial0/2
     2.0.0.0/24 is subnetted, 1 subnets
C       2.2.2.0 is directly connected, Loopback0
     3.0.0.0/32 is subnetted, 1 subnets
O       3.3.3.3 [110/65] via 192.1.1.3, 00:03:22, Serial0/2
C    192.1.1.0/24 is directly connected, Serial0/2

routerC#sh ip route
Gateway of last resort is not set

     1.0.0.0/32 is subnetted, 1 subnets
O       1.1.1.1 [110/65] via 192.1.1.1, 00:03:25, Serial0/3
     2.0.0.0/32 is subnetted, 1 subnets
O       2.2.2.2 [110/65] via 192.1.1.2, 00:03:25, Serial0/3
     3.0.0.0/24 is subnetted, 1 subnets
C       3.3.3.0 is directly connected, Loopback0
C    192.1.1.0/24 is directly connected, Serial0/3

如果把routerB的优先级改成10，重启后routerB会成为DR，routerA为BDR，routerC为DROTHER

routerB(config)#interface s0/2
routerB(config-if)#ip os pri 10

routerC#sh ip route
Gateway of last resort is not set

     3.0.0.0/24 is subnetted, 1 subnets
C       3.3.3.0 is directly connected, Loopback0
C    192.1.1.0/24 is directly connected, Serial0/3

因为Adv Router 不可达，因此routerC不能学到路由

routerC#sh ip ospf database

            OSPF Router with ID (3.3.3.3) (Process ID 10)

                Router Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum Link count
1.1.1.1         1.1.1.1         137         0x8000000B 0x00B78C 2
2.2.2.2         2.2.2.2         140         0x80000007 0x00D367 2
3.3.3.3         3.3.3.3         139         0x80000009 0x00D953 2

                Net Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum
192.1.1.2       2.2.2.2         142         0x80000001 0x00E47C

routerC#sh ip ospf database router

            OSPF Router with ID (3.3.3.3) (Process ID 10)

                Router Link States (Area 0)

  Adv Router is not-reachable
  LS age: 160
  Options: (No TOS-capability, DC)
  LS Type: Router Links
  Link State ID: 1.1.1.1
  Advertising Router: 1.1.1.1
  LS Seq Number: 8000000B
  Checksum: 0xB78C
  Length: 48
  Number of Links: 2

    Link connected to: a Transit Network
     (Link ID) Designated Router address: 192.1.1.2
     (Link Data) Router Interface address: 192.1.1.1
      Number of TOS metrics: 0
       TOS 0 Metrics: 64

    Link connected to: a Stub Network
     (Link ID) Network/subnet number: 1.1.1.1
     (Link Data) Network Mask: 255.255.255.255
      Number of TOS metrics: 0
       TOS 0 Metrics: 1

  Adv Router is not-reachable
  LS age: 166
  Options: (No TOS-capability, DC)
  LS Type: Router Links
  Link State ID: 2.2.2.2
  Advertising Router: 2.2.2.2
  LS Seq Number: 80000007
  Checksum: 0xD367
  Length: 48
  Number of Links: 2

    Link connected to: a Transit Network
     (Link ID) Designated Router address: 192.1.1.2
     (Link Data) Router Interface address: 192.1.1.2
      Number of TOS metrics: 0
       TOS 0 Metrics: 64

    Link connected to: a Stub Network
     (Link ID) Network/subnet number: 2.2.2.2
     (Link Data) Network Mask: 255.255.255.255
      Number of TOS metrics: 0
       TOS 0 Metrics: 1

         
  LS age: 169
  Options: (No TOS-capability, DC)
  LS Type: Router Links
  Link State ID: 3.3.3.3
  Advertising Router: 3.3.3.3
  LS Seq Number: 80000009
  Checksum: 0xD953
  Length: 48
  Number of Links: 2

    Link connected to: a Transit Network
     (Link ID) Designated Router address: 192.1.1.1
     (Link Data) Router Interface address: 192.1.1.3
      Number of TOS metrics: 0
       TOS 0 Metrics: 64

    Link connected to: a Stub Network
     (Link ID) Network/subnet number: 3.3.3.3
     (Link Data) Network Mask: 255.255.255.255
      Number of TOS metrics: 0
       TOS 0 Metrics: 1