R1 CONFIGURATION 
------------------

R1#sh run
Building configuration...

Current configuration : 1668 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R1
!
!
no ip domain lookup
!
!
interface Loopback0
 ip address 1.1.1.1 255.255.255.0
!
interface FastEthernet0/0
 ip address 10.1.1.1 255.255.255.0
 duplex auto
 speed auto
!
interface Serial0/0
 ip address 172.12.123.1 255.255.255.0
 encapsulation frame-relay
 clock rate 2000000
 frame-relay map ip 172.12.123.3 123 broadcast
 frame-relay map ip 172.12.123.2 122 broadcast
 no frame-relay inverse-arp
!
router ospf 1
 log-adjacency-changes
 network 10.1.1.0 0.0.0.255 area 0
 network 172.12.123.0 0.0.0.255 area 0
!
-----------------------------------------------------------------------------








R2 CONFIGURATION
-----------------
R2#sh run
Building configuration...

*Mar  1 09:56:20.321: %SYS-5-CONFIG_I: Configured from console by console
Current configuration : 1587 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R2
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
no ip icmp rate-limit unreachable
ip cef
!
!
!
!
no ip domain lookup
!
multilink bundle-name authenticated
!
!

!
interface Serial0/0
 ip address 172.12.123.2 255.255.255.0
 encapsulation frame-relay
 ip ospf priority 0
 clock rate 2000000
 frame-relay map ip 172.12.123.3 221 broadcast
 frame-relay map ip 172.12.123.1 221 broadcast
 no frame-relay inverse-arp
!
router ospf 1
 log-adjacency-changes
 network 172.12.123.0 0.0.0.255 area 0
!
-----------------------------------------------------------





R3 CONFIGURATION
------------------


R3#sh run
Building configuration...

Current configuration : 1587 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R3
!
boot-start-marker
boot-end-marker
!
no ip domain lookup
!
!
interface Serial0/0
 ip address 172.12.123.3 255.255.255.0
 encapsulation frame-relay
 ip ospf priority 0
 clock rate 2000000
 frame-relay map ip 172.12.123.2 321 broadcast
 frame-relay map ip 172.12.123.1 321 broadcast
 no frame-relay inverse-arp
!

router ospf 1
 log-adjacency-changes
 network 172.12.123.0 0.0.0.255 area 0