一直以为OSPF多进程之间要互通的话需要重发布，但是在实际工作中发现两个不通的ospf进程，发布互联的网段，竟然可以互相学习到路由。如下：
配置如下：
R1：
interface Loopback0
ip address 1.1.1.1 255.255.255.0
!
interface FastEthernet0/0
ip address 12.12.12.1 255.255.255.0
duplex half
!
router ospf 2
network 1.1.1.0 0.0.0.255 area 0
network 12.12.12.0 0.0.0.255 area 0
R2：
interface Loopback0
ip address 2.2.2.2 255.255.255.0
!
interface FastEthernet0/0
ip address 12.12.12.2 255.255.255.0
duplex half
!
interface GigabitEthernet1/0
ip address 23.23.23.1 255.255.255.0
negotiation auto
!
router ospf 1
network 2.2.2.0 0.0.0.255 area 0
network 12.12.12.0 0.0.0.255 area 0
network 23.23.23.0 0.0.0.255 area 0
R3:
interface Loopback0
ip address 3.3.3.3 255.255.255.0
!
interface FastEthernet0/0
ip address 23.23.23.2 255.255.255.0
duplex half
!
router ospf 1
network 3.3.3.0 0.0.0.255 area 0
network 23.23.23.0 0.0.0.255 area 0
路由表如下：
R1
R2
R3
R1可以ping通R3