Lab 18 - OSPF FA Suppression in Translated Type-5 LSAs

Lab 18 - OSPF FA Suppression in Translated Type-5 LSAs
Di Posting Oleh : Simple Learning
Kategori : Core Technologies OSPF Routing

Prerequisites: CCNP level skills.

Personal Note
Found this little contraption at:
http://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ftoadsup.html

Topology

Pic. 1 - OSPF

Icons designed by: Andrzej Szoblik - http://www.newo.pl

Task 1

Configure IP addresses and OSPF according to the topology diagram (pic. 1). Advertise loopback interfaces in the appropriate areas as stub networks.

Task 2
Create a loopback1 interface on R3 with IP address 192.168.3.3/24.

Task 3
Configure area 13 as NSSA. Redistribute R3's loopback1 interface into OSPF.

Task 4
Verify if R1 receives the E2 prefix 192.168.3.0/24.

Task 5
On ABR filter out 172.16.103.3/32. R2 should not receive 192.168.3.0/24 anymore. The reason: the forwarding address (172.16.103.3) is no longer reachable.

Task 6
Change the forwarding address for 192.168.3.0/24 so R1 becomes the gateway (forwarding address = 0.0.0.0).

Lab Solution

Task 1

Configure IP addresses and OSPF according to the topology diagram (pic. 1). Advertise loopback interfaces in the appropriate areas as stub networks.

R1 OSPF Configuration:

!
router ospf 1
 router-id 1.1.1.1
 log-adjacency-changes
 network 10.1.12.1 0.0.0.0 area 0
 network 10.1.13.1 0.0.0.0 area 13
 network 172.16.101.1 0.0.0.0 area 0

!

R2 OSPF Configuration:

!

router ospf 1
 router-id 2.2.2.2
 log-adjacency-changes
 network 10.1.12.2 0.0.0.0 area 0
 network 172.16.102.2 0.0.0.0 area 0

!

R3 OSPF Configuration:

!
router ospf 1
 router-id 3.3.3.3
 log-adjacency-changes
 network 10.1.13.3 0.0.0.0 area 13
 network 172.16.103.3 0.0.0.0 area 13

!

Task 2

Create a loopback1 interface on R3 with IP address 192.168.3.3/24.

R3 Configuration:

!

interface Loopback1
 ip address 192.168.3.3 255.255.255.0

!

Task 3

Configure area 13 as NSSA. Redistribute R3's loopback1 interface into OSPF.

R1 Configuration:

!

router ospf 1
 router-id 1.1.1.1
 log-adjacency-changes
 area 13 nssa
 network 10.1.12.1 0.0.0.0 area 0
 network 10.1.13.1 0.0.0.0 area 13
 network 172.16.101.1 0.0.0.0 area 0

!

R3 Configuration:

!

router ospf 1
 router-id 3.3.3.3
 log-adjacency-changes
 area 13 nssa
 redistribute connected subnets
 network 10.1.13.3 0.0.0.0 area 13
 network 172.16.103.3 0.0.0.0 area 13
!

Verification:

Pic. 2 - R3's OSPF Database (NSSA).

Pic. 3 - R1's OSPF Database (NSSA).

Pic. 4 - R1 OSPF Database (External).

Note!

On all routers R3's loopback becomes the forwarding address to 192.168.3.0/24.

Note!
I removed OSPF from R3 and re-created it, but this time R3 does NOT advertise 172.16.103.3/32.

R3 New OSPF Configuration:

!

router ospf 1
 router-id 3.3.3.3
 log-adjacency-changes
 area 13 nssa
 redistribute connected subnets
 network 10.1.13.3 0.0.0.0 area 13
!

Note!
Without loopback0 (172.16.103.3) being advertised on R3, all routers use 10.1.13.3 as the forwarding address. It must be reachable in order to get to 192.168.3.0/24.

(I have brought back the original configuration on R3 (with loopback0 being advertised.)

Task 4
Verify if R1 receives the E2 prefix 192.168.3.0/24.

Pic. 5 - R2 Receives 192.168.3.0/24 (forwarding address 172.16.103.3)

Task 5

On ABR filter out 172.16.103.3/32. R2 should not receive 192.168.3.0/24 anymore. The reason: the forwarding address (172.16.103.3) is no longer reachable.

R1 Configuration:

!

router ospf 1
 router-id 1.1.1.1
 log-adjacency-changes
 area 13 nssa
 area 13 range 172.16.103.0 255.255.255.0 not-advertise
 network 10.1.12.1 0.0.0.0 area 0
 network 10.1.13.1 0.0.0.0 area 13
 network 172.16.101.1 0.0.0.0 area 0

!

Verification:

Pic. 6 - R2 Routing Table Missing.

Note!
The forwarding address 172.16.103.3 has been filtered out and is inaccessible. As a result of that, 192.168.3.0/24 cannot be used in the routing table.

Pic. 7 - R2 OSPF Database External.

 

Task 6
Change the forwarding address for 192.168.3.0/24 so R1 becomes the gateway (forwarding address = 0.0.0.0).

R1 Configuration:

!

router ospf 1
 router-id 1.1.1.1
 log-adjacency-changes
 area 13 nssa translate type7 suppress-fa
 area 13 range 172.16.103.0 255.255.255.0 not-advertise
 network 10.1.12.1 0.0.0.0 area 0
 network 10.1.13.1 0.0.0.0 area 13
 network 172.16.101.1 0.0.0.0 area 0

!

Verification: 

Pic. 8 - R2 Routing Table.

Pic. 9 - R2's OSPF Database (External).

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