OSPF Neighbor Authentication

Neighbor authentication is pretty straightforward, there is a clear text and md5 option. I show the md5 option, clear test is similar just minus the md5 stuff in the command. Adjacencies will break when setting up authentication.

R1(config-if)#ip ospf authentication message-digest

R1(config-if)#ip ospf message-digest-key 1 md5 CCNP

R1(config-if)#
R1#
*Mar  1 01:03:18.335: %SYS-5-CONFIG_I: Configured from console by console
*Mar  1 01:03:23.375: %OSPF-5-ADJCHG: Process 1, Nbr 2.2.2.2 on Serial0/0 from FULL to DOWN, Neighbor Down: Dead timer expired
*Mar  1 01:03:35.407: %OSPF-5-ADJCHG: Process 1, Nbr 3.3.3.3 on Serial0/0 from FULL to DOWN, Neighbor Down: Dead timer expired

R2(config)#interface serial 0/0

R2(config-if)#ip ospf authentication message-digest

R2(config-if)#ip ospf message-digest-key 1 md5 CCNP

R3(config)#int serial 0/0

R3(config-if)#ip ospf message-digest-key 1 md5 CCNP

R3(config-if)#ip ospf authentication message-digest

R1#show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface

2.2.2.2           0   FULL/DROTHER    00:01:46    172.12.123.2    Serial0/0

3.3.3.3           0   FULL/DROTHER    00:01:58    172.12.123.3    Serial0/0

OSPF Area-Based Route Summarization

Area 0 can't  be a stub area so if you need to reduce the routing table there is also route summarization. Looking at R3 I can see the OSPF table is bit lengthy, so I will summarize both IA and E1 routes. E2 is the default OSPF external route type but I changed it with the metric-type command when I redistributed them into OSPF. There are two different ways to summarize routes depending on the type of routes you want summarize. First I will redistribute inter-area routes using the area range command. I will summarize 8.0.0.0,9.0.0.0 and 10.0.0.0. The binary results gives me a 8.0.0.0 248.0.0.0 summary address. The area is the area in which the routes originated from not where they are going for the area range command.



R3#show ip route ospf
     1.0.0.0/32 is subnetted, 1 subnets
O IA    1.1.1.1 [110/65] via 172.12.123.1, 00:07:11, Serial0/0
     2.0.0.0/32 is subnetted, 1 subnets
O IA    2.2.2.2 [110/65] via 172.12.123.2, 00:07:11, Serial0/0
     5.0.0.0/32 is subnetted, 1 subnets
O E1    5.1.1.1 [110/84] via 172.12.123.1, 00:03:54, Serial0/0
     6.0.0.0/32 is subnetted, 1 subnets
O E1    6.1.1.1 [110/84] via 172.12.123.1, 00:03:54, Serial0/0
     7.0.0.0/32 is subnetted, 1 subnets
O E1    7.1.1.1 [110/84] via 172.12.123.1, 00:03:54, Serial0/0
     8.0.0.0/32 is subnetted, 1 subnets
O IA    8.1.1.1 [110/65] via 172.12.123.1, 00:00:02, Serial0/0
     9.0.0.0/32 is subnetted, 1 subnets
O IA    9.1.1.1 [110/65] via 172.12.123.1, 00:00:02, Serial0/0
     10.0.0.0/32 is subnetted, 1 subnets
O IA    10.1.1.1 [110/65] via 172.12.123.1, 00:00:02, Serial0/0
     15.0.0.0/24 is subnetted, 1 subnets
O E1    15.1.1.0 [110/84] via 172.12.123.1, 00:03:54, Serial0/0

R1(config)#router ospf 1
R1(config-router)#area 1 range 8.0.0.0 248.0.0.0 

I can see that the routes are not summarize into OIA 8.0.0.0/5, the route is smaller but now I will summarize the external routes.



R3#show ip route ospf
     1.0.0.0/32 is subnetted, 1 subnets
O IA    1.1.1.1 [110/65] via 172.12.123.1, 00:06:35, Serial0/0
     2.0.0.0/32 is subnetted, 1 subnets
O IA    2.2.2.2 [110/65] via 172.12.123.2, 00:06:35, Serial0/0
     5.0.0.0/32 is subnetted, 1 subnets
O E1    5.1.1.1 [110/84] via 172.12.123.1, 00:03:18, Serial0/0
     6.0.0.0/32 is subnetted, 1 subnets
O E1    6.1.1.1 [110/84] via 172.12.123.1, 00:03:18, Serial0/0
     7.0.0.0/32 is subnetted, 1 subnets
O E1    7.1.1.1 [110/84] via 172.12.123.1, 00:03:18, Serial0/0
     15.0.0.0/24 is subnetted, 1 subnets
O E1    15.1.1.0 [110/84] via 172.12.123.1, 00:03:18, Serial0/0
O IA 8.0.0.0/5 [110/65] via 172.12.123.1, 00:03:23, Serial0/0

To summarize external routes I use the command summary-address, the routes are 5.1.1.1,6.1.1.1.1,7.1.1.1 that I want summarize. The binary result gives me 4.0.0.0 with a mask of 252.0.0.0.

R1(config)#router ospf 1

R1(config-router)#summary-address 4.0.0.0 252.0.0.0

I can now see the summary address of O E1 4.0.0.0, the summary address takes the type of the routes being summarize. The ip routing table is now much smaller. Connectivity is still working.

R3#show ip route ospf

     1.0.0.0/32 is subnetted, 1 subnets

O IA    1.1.1.1 [110/65] via 172.12.123.1, 00:13:43, Serial0/0

     2.0.0.0/32 is subnetted, 1 subnets

O IA    2.2.2.2 [110/65] via 172.12.123.2, 00:13:43, Serial0/0

     15.0.0.0/24 is subnetted, 1 subnets

O E1    15.1.1.0 [110/84] via 172.12.123.1, 00:06:13, Serial0/0

O E1 4.0.0.0/6 [110/84] via 172.12.123.1, 00:00:01, Serial0/0

O IA 8.0.0.0/5 [110/65] via 172.12.123.1, 00:06:18, Serial0/0

R3#ping 5.1.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 5.1.1.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 32/49/88 ms

R3#

OSPF NSSA-NSSTSA

The general rule with OSPF is that you can't make an ASBR  a stub router but it is possible by bending the rules with a Not So Stubby Area. At this point the above configuration has been configured. What if we needed R3 to be an ASBR by redistributing another ospf route 14.14.14.14, area 34 could not be a stub area anymore because of the stub network rules. NSSA uses Type 7 LSAs to allow this breakage of the rules.


R3(config)#int lo14

R3(config-if)#ip address 14.14.14.14 255.255.255.255
R3(config-if)#router ospf 1
R3(config-router)#redistribute connected subnets

R1#show ip route ospf

     2.0.0.0/32 is subnetted, 1 subnets

O IA    2.2.2.2 [110/65] via 172.12.123.2, 00:01:02, Serial0/0

     3.0.0.0/32 is subnetted, 1 subnets

O IA    3.3.3.3 [110/65] via 172.12.123.3, 00:01:02, Serial0/0

     172.34.0.0/24 is subnetted, 1 subnets

O IA    172.34.34.0 [110/65] via 172.12.123.3, 00:01:02, Serial0/0

     14.0.0.0/32 is subnetted, 1 subnets

O E2    14.14.14.14 [110/20] via 172.12.123.3, 00:01:02, Serial0/0

R1#show ip route rip  

R    5.0.0.0/8 [120/1] via 15.0.0.5, 00:00:21, FastEthernet0/0

R    6.0.0.0/8 [120/1] via 15.0.0.5, 00:00:21, FastEthernet0/0

R    7.0.0.0/8 [120/1] via 15.0.0.5, 00:00:21, FastEthernet0/0

R2#show ip route ospf 

     1.0.0.0/32 is subnetted, 1 subnets

O IA    1.1.1.1 [110/65] via 172.12.123.1, 00:06:53, Serial0/0

     3.0.0.0/32 is subnetted, 1 subnets

O IA    3.3.3.3 [110/65] via 172.12.123.3, 00:06:53, Serial0/0

O E2 5.0.0.0/8 [110/20] via 172.12.123.1, 00:00:41, Serial0/0

O E2 6.0.0.0/8 [110/20] via 172.12.123.1, 00:00:41, Serial0/0

     172.34.0.0/24 is subnetted, 1 subnets

O IA    172.34.34.0 [110/65] via 172.12.123.3, 00:06:53, Serial0/0

O E2 7.0.0.0/8 [110/20] via 172.12.123.1, 00:00:41, Serial0/0

O E2 15.0.0.0/8 [110/20] via 172.12.123.1, 00:00:31, Serial0/0

R3#show ip route ospf 

     1.0.0.0/32 is subnetted, 1 subnets

O IA    1.1.1.1 [110/65] via 172.12.123.1, 00:07:28, Serial0/0

     2.0.0.0/32 is subnetted, 1 subnets

O IA    2.2.2.2 [110/65] via 172.12.123.2, 00:07:28, Serial0/0

O E2 5.0.0.0/8 [110/20] via 172.12.123.1, 00:01:16, Serial0/0

O E2 6.0.0.0/8 [110/20] via 172.12.123.1, 00:01:16, Serial0/0

O E2 7.0.0.0/8 [110/20] via 172.12.123.1, 00:01:16, Serial0/0

O E2 15.0.0.0/8 [110/20] via 172.12.123.1, 00:01:06, Serial0/0

R4#show ip route ospf 

     1.0.0.0/32 is subnetted, 1 subnets

O IA    1.1.1.1 [110/66] via 172.34.34.3, 00:10:16, FastEthernet0/0

     2.0.0.0/32 is subnetted, 1 subnets

O IA    2.2.2.2 [110/66] via 172.34.34.3, 00:10:16, FastEthernet0/0

     3.0.0.0/32 is subnetted, 1 subnets

O IA    3.3.3.3 [110/2] via 172.34.34.3, 00:10:16, FastEthernet0/0

O E2 5.0.0.0/8 [110/20] via 172.34.34.3, 00:00:34, FastEthernet0/0

O E2 6.0.0.0/8 [110/20] via 172.34.34.3, 00:00:34, FastEthernet0/0

     172.12.0.0/24 is subnetted, 1 subnets

O IA    172.12.123.0 [110/65] via 172.34.34.3, 00:10:16, FastEthernet0/0

O E2 7.0.0.0/8 [110/20] via 172.34.34.3, 00:00:34, FastEthernet0/0

O E2 15.0.0.0/8 [110/20] via 172.34.34.3, 00:00:24, FastEthernet0/0

R5#show ip route rip

     1.0.0.0/32 is subnetted, 1 subnets

R       1.1.1.1 [120/2] via 15.0.0.1, 00:00:06, FastEthernet0/0

     2.0.0.0/32 is subnetted, 1 subnets

R       2.2.2.2 [120/2] via 15.0.0.1, 00:00:06, FastEthernet0/0

     3.0.0.0/32 is subnetted, 1 subnets

R       3.3.3.3 [120/2] via 15.0.0.1, 00:00:06, FastEthernet0/0

     172.12.0.0/24 is subnetted, 1 subnets

R       172.12.123.0 [120/2] via 15.0.0.1, 00:00:06, FastEthernet0/0

     172.34.0.0/24 is subnetted, 1 subnets

R       172.34.34.0 [120/2] via 15.0.0.1, 00:00:06, FastEthernet0/0

Now we want to make our routing tables complete yet concise and realize that R4 next hop address are all through area 34 to R3. We want to create a stub area but we can't because R3 is ASBR but with the NSSA command we still can. 

R3(config-router)#area 34 nssa    

R3(config-router)#

*Mar  1 00:47:59.031: %OSPF-5-ADJCHG: Process 1, Nbr 172.34.34.4 on FastEthernet0/0 from FULL to DOWN, Neighbor Down: Adjacency forced to reset

R4(config-router)#area 34 nssa

R4(config-router)#

*Mar  1 00:48:15.069: %OSPF-5-ADJCHG: Process 1, Nbr 3.3.3.3 on FastEthernet0/0 from FULL to DOWN, Neighbor Down: Adjacency forced to reset

*Mar  1 00:48:18.711: %OSPF-5-ADJCHG: Process 1, Nbr 3.3.3.3 on FastEthernet0/0 from LOADING to FULL, Loading Done

R4 now has all external routes removed from the table but we can still make it smaller by using the no summary command, which is called a not so stubby total stub area.

R4#show ip route ospf 

     1.0.0.0/32 is subnetted, 1 subnets

O IA    1.1.1.1 [110/66] via 172.34.34.3, 00:00:24, FastEthernet0/0

     2.0.0.0/32 is subnetted, 1 subnets

O IA    2.2.2.2 [110/66] via 172.34.34.3, 00:00:24, FastEthernet0/0

     3.0.0.0/32 is subnetted, 1 subnets

O IA    3.3.3.3 [110/2] via 172.34.34.3, 00:00:24, FastEthernet0/0

     172.12.0.0/24 is subnetted, 1 subnets

O IA    172.12.123.0 [110/65] via 172.34.34.3, 00:00:24, FastEthernet0/0

     14.0.0.0/32 is subnetted, 1 subnets

O N2    14.14.14.14 [110/20] via 172.34.34.3, 00:00:24, FastEthernet0/0

R3(config-router)#area 34 nssa no-summary 

R4(config-router)#area 34 nssa no-summary

R4 has a default no summary route now like we had before with a total stub area.

R4#show ip route ospf 

     14.0.0.0/32 is subnetted, 1 subnets

O N2    14.14.14.14 [110/20] via 172.34.34.3, 00:00:23, FastEthernet0/0

O*IA 0.0.0.0/0 [110/2] via 172.34.34.3, 00:00:28, FastEthernet0/0

Starting up Blog Again

I took a break from studying for my CCNP. I'm back on track and should be taking the route exam in a few weeks.

OSPF Stub and Total Stub Area

Router 1 has a view of all networks , without redistribution the others won't learn all networks

R1#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
     1.0.0.0/32 is subnetted, 1 subnets
C       1.1.1.1 is directly connected, Loopback0
     2.0.0.0/32 is subnetted, 1 subnets
O IA    2.2.2.2 [110/65] via 172.12.123.2, 00:31:01, Serial0/0
     3.0.0.0/32 is subnetted, 1 subnets
O IA    3.3.3.3 [110/65] via 172.12.123.3, 00:31:01, Serial0/0
R    5.0.0.0/8 [120/1] via 15.0.0.5, 00:00:27, FastEthernet0/0
R    6.0.0.0/8 [120/1] via 15.0.0.5, 00:00:27, FastEthernet0/0
     172.12.0.0/24 is subnetted, 1 subnets
C       172.12.123.0 is directly connected, Serial0/0
     172.34.0.0/24 is subnetted, 1 subnets
O IA    172.34.34.0 [110/65] via 172.12.123.3, 00:31:01, Serial0/0
R    7.0.0.0/8 [120/1] via 15.0.0.5, 00:00:27, FastEthernet0/0
C    15.0.0.0/8 is directly connected, FastEthernet0/0

R5#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

C    5.0.0.0/8 is directly connected, Loopback0
C    6.0.0.0/8 is directly connected, Loopback1
C    7.0.0.0/8 is directly connected, Loopback2
C    15.0.0.0/8 is directly connected, FastEthernet0/0

R5#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

C    5.0.0.0/8 is directly connected, Loopback0
C    6.0.0.0/8 is directly connected, Loopback1
C    7.0.0.0/8 is directly connected, Loopback2
C    15.0.0.0/8 is directly connected, FastEthernet0/0

Redistributing OSPF routes into RIP is fairly easy, only a seed metric is needed because RIP has a max hop count of 16. Connected routes will need to be redistributed as well because connectivity won't be possible for all routes.  

R1(config)#router rip

R1(config-router)#redistribute ospf 1 metric 2

R1(config-router)#redistribute connected metric 2

I now have one way redistribute. I can see the OSPF routes on R5 coming in as RIP. Below I tried to ping one of the newly added routes but I was unsuccessful because the OSPF networks do not know how to reach the RIP routes.

R5#show ip route rip 

     1.0.0.0/32 is subnetted, 1 subnets

R       1.1.1.1 [120/1] via 15.0.0.1, 00:00:23, FastEthernet0/0

     2.0.0.0/32 is subnetted, 1 subnets

R       2.2.2.2 [120/2] via 15.0.0.1, 00:00:23, FastEthernet0/0

     3.0.0.0/32 is subnetted, 1 subnets

R       3.3.3.3 [120/2] via 15.0.0.1, 00:00:23, FastEthernet0/0

     172.12.0.0/24 is subnetted, 1 subnets

R       172.12.123.0 [120/1] via 15.0.0.1, 00:00:23, FastEthernet0/0

     172.34.0.0/24 is subnetted, 1 subnets

R       172.34.34.0 [120/2] via 15.0.0.1, 00:00:23, FastEthernet0/0

Failed ping without two-way redistribution 

R5#ping 172.34.34.4

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.34.34.4, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

Here I redistributed RIP into OSPF with the subnet commands. This is important because we want the subnets to be in the routes and not just the classful boundaries. 

R1(config)#router ospf 1

R1(config-router)#redistribute rip subnets 

R1(config-router)#redistribute connected subnets


I can see here that R4 now can see the RIP routes in it's routing table. The code OE2 are the rip routes, it stands for OSPF learned external type 2 route. The default is type 2 (metric from last router), type 1 is another type (metric from destination router)

R4#show ip route ospf 

     1.0.0.0/32 is subnetted, 1 subnets

O IA    1.1.1.1 [110/66] via 172.34.34.3, 00:43:39, FastEthernet0/0

     2.0.0.0/32 is subnetted, 1 subnets

O IA    2.2.2.2 [110/66] via 172.34.34.3, 00:43:39, FastEthernet0/0

     3.0.0.0/32 is subnetted, 1 subnets

O IA    3.3.3.3 [110/2] via 172.34.34.3, 00:43:40, FastEthernet0/0

O E2 5.0.0.0/8 [110/20] via 172.34.34.3, 00:00:58, FastEthernet0/0

O E2 6.0.0.0/8 [110/20] via 172.34.34.3, 00:00:58, FastEthernet0/0

     172.12.0.0/24 is subnetted, 1 subnets

O IA    172.12.123.0 [110/65] via 172.34.34.3, 00:43:40, FastEthernet0/0

O E2 7.0.0.0/8 [110/20] via 172.34.34.3, 00:00:58, FastEthernet0/0

O E2 15.0.0.0/8 [110/20] via 172.34.34.3, 00:00:58, FastEthernet0/0

Now the pings are successful across the network.

R5#ping 172.34.34.4

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.34.34.4, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 4/14/40 ms

Creating a stub in OSPF is needed when I want to reduce the size of the routing table. Looking up R4 routing table I can see that the exit interface for all routes ifs fastethernet 0/0. Unlike RIP and EIGRP, OSPF stub in configured per area not interface.

R3(config)#router ospf 1

R3(config-router)#area 34 stub 

R4(config)#router ospf 1

R4(config-router)#area 34 stub

Inter-area routes are still here but the external routes have been stubbed

R4#show ip route ospf 

     1.0.0.0/32 is subnetted, 1 subnets

O IA    1.1.1.1 [110/66] via 172.34.34.3, 03:18:10, FastEthernet0/0

     2.0.0.0/32 is subnetted, 1 subnets

O IA    2.2.2.2 [110/66] via 172.34.34.3, 03:18:10, FastEthernet0/0

     3.0.0.0/32 is subnetted, 1 subnets

O IA    3.3.3.3 [110/2] via 172.34.34.3, 03:18:10, FastEthernet0/0

     172.12.0.0/24 is subnetted, 1 subnets

O IA    172.12.123.0 [110/65] via 172.34.34.3, 03:18:10, FastEthernet0/0

O*IA 0.0.0.0/0 [110/2] via 172.34.34.3, 03:18:10, FastEthernet0/0

A total stub area will summarized inter-area routes as well

R3(config)#router ospf 1

R3(config-router)# area 34 stub  no-summary

Now I have a Total Stub Area with only one OSPF route

R4#show ip route ospf 

O*IA 0.0.0.0/0 [110/2] via 172.34.34.3, 00:01:14, FastEthernet0/0

OSPF Virtual Links & Redistribution

Router 4 has a problem because it has an area that isn't on a router directly connected to the backbone (area 0) The loopback 4.4.4.4 will not be reachable unless we create a virtual link to area 0. Also R5, will not be able to communicate with the rest of the network unless it uses route redistribution.


R1#show ip route ospf 
     2.0.0.0/32 is subnetted, 1 subnets
O IA    2.2.2.2 [110/65] via 172.12.123.2, 00:02:08, Serial0/0
     3.0.0.0/32 is subnetted, 1 subnets
O IA    3.3.3.3 [110/65] via 172.12.123.3, 00:02:08, Serial0/0
O IA 192.168.1.0/24 [110/65] via 172.12.123.2, 00:02:08, Serial0/0
R1#ping 4.4.4.4

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 4.4.4.4, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
R1#ping 5.5.5.5

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 5.5.5.5, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

R4(config)#router ospf 1

R4(config-router)#area 13 virtual-link 2.2.2.2

R2#

*Mar  1 02:08:55.195: %OSPF-4-ERRRCV: Received invalid packet: mismatch area ID, from backbone area must be virtual-link but not found from 192.168.1.4, FastEthernet0/0

R2(config)#router ospf 1                  

R2(config-router)#area 13 virtual-link 4.4.4.4   

R2(config-router)#

*Mar  1 02:10:15.134: %OSPF-4-ERRRCV: Received invalid packet: mismatch area ID, from backbone area must be virtual-link but not found from 192.168.1.4, FastEthernet0/0

*Mar  1 02:10:16.933: %OSPF-5-ADJCHG: Process 1, Nbr 4.4.4.4 on OSPF_VL1 from LOADING to FULL, Loading Done

R1#show ip route ospf 

     2.0.0.0/32 is subnetted, 1 subnets

O IA    2.2.2.2 [110/65] via 172.12.123.2, 00:01:18, Serial0/0

     3.0.0.0/32 is subnetted, 1 subnets

O IA    3.3.3.3 [110/65] via 172.12.123.3, 00:01:18, Serial0/0

     4.0.0.0/32 is subnetted, 1 subnets

O IA    4.4.4.4 [110/66] via 172.12.123.2, 00:01:18, Serial0/0

O IA 192.168.1.0/24 [110/65] via 172.12.123.2, 00:01:18, Serial0/0

R1#ping 4.4.4.4       

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 4.4.4.4, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 24/34/40 ms

R5#show ip route rip

R5#

R3(config)#router ospf 1

R3(config-router)#redistribute rip subnets 

R3(config)#router rip

R3(config-router)#redistribute ospf 1 metric 2

R5#show ip route rip

     1.0.0.0/32 is subnetted, 1 subnets

R       1.1.1.1 [120/2] via 10.1.1.3, 00:00:04, FastEthernet0/0

     2.0.0.0/32 is subnetted, 1 subnets

R       2.2.2.2 [120/2] via 10.1.1.3, 00:00:04, FastEthernet0/0

     3.0.0.0/32 is subnetted, 1 subnets

R       3.3.3.3 [120/2] via 10.1.1.3, 00:00:04, FastEthernet0/0

     4.0.0.0/32 is subnetted, 1 subnets

R       4.4.4.4 [120/2] via 10.1.1.3, 00:00:04, FastEthernet0/0

     172.12.0.0/24 is subnetted, 1 subnets

R       172.12.123.0 [120/2] via 10.1.1.3, 00:00:04, FastEthernet0/0

R    192.168.1.0/24 [120/2] via 10.1.1.3, 00:00:04, FastEthernet0/0

R1#show ip route ospf 

     2.0.0.0/32 is subnetted, 1 subnets

O IA    2.2.2.2 [110/65] via 172.12.123.2, 00:04:06, Serial0/0

     3.0.0.0/32 is subnetted, 1 subnets

O IA    3.3.3.3 [110/65] via 172.12.123.3, 00:04:06, Serial0/0

     4.0.0.0/32 is subnetted, 1 subnets

O IA    4.4.4.4 [110/66] via 172.12.123.2, 00:04:06, Serial0/0

     5.0.0.0/32 is subnetted, 1 subnets

O E2    5.5.5.5 [110/20] via 172.12.123.3, 00:04:06, Serial0/0

     10.0.0.0/24 is subnetted, 1 subnets

O E2    10.1.1.0 [110/20] via 172.12.123.3, 00:04:06, Serial0/0

O IA 192.168.1.0/24 [110/65] via 172.12.123.2, 00:04:06, Serial0/0

R1#ping 5.5.5.5       

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 5.5.5.5, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 24/33/40 ms

OSPF Multi-Area

OSPF is a hierarchical because it allows the configuration of multi-areas. Having a layer approach does benefit an organization by having more efficient and concise routing tables, less SPF recalculations and less LSU and LSA traffic. Areas can retain problem from spreading across the enterprise. Below I configured OSPF on each router with their respect areas.

In this frame relay topology, the hub is the only DR and the spokes have been manually remove from the election process.

R1#show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
2.2.2.2           0   FULL/DROTHER    00:01:53    172.12.123.2    Serial0/0
3.3.3.3           0   FULL/DROTHER    00:01:43    172.12.123.3    Serial0/0

Here is some more useful information about the setup. I can see that the network type is non-broadcast, that R1 is the DR, the timer intervals are set at default .

R1#show ip ospf interface

Serial0/0 is up, line protocol is up

  Internet Address 172.12.123.1/24, Area 0

  Process ID 1, Router ID 1.1.1.1, Network Type NON_BROADCAST, Cost: 64

  Transmit Delay is 1 sec, State DR, Priority 1

  Designated Router (ID) 1.1.1.1, Interface address 172.12.123.1

  No backup designated router on this network

  Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5

    oob-resync timeout 120

    Hello due in 00:00:29

  Index 1/1, flood queue length 0

  Next 0x0(0)/0x0(0)

  Last flood scan length is 1, maximum is 3

  Last flood scan time is 0 msec, maximum is 4 msec

  Neighbor Count is 2, Adjacent neighbor count is 2

    Adjacent with neighbor 2.2.2.2

    Adjacent with neighbor 3.3.3.3

  Suppress hello for 0 neighbor(s)

Loopback0 is up, line protocol is up

  Internet Address 1.1.1.1/32, Area 1

  Process ID 1, Router ID 1.1.1.1, Network Type LOOPBACK, Cost: 1

  Loopback interface is treated as a stub Host

IP routes with the O IA  label are inter-area routes learned by OSPF.

R1#show ip route ospf
     2.0.0.0/32 is subnetted, 1 subnets
O IA    2.2.2.2 [110/65] via 172.12.123.2, 00:06:30, Serial0/0
     3.0.0.0/32 is subnetted, 1 subnets
O IA    3.3.3.3 [110/65] via 172.12.123.3, 00:06:30, Serial0/0