Task 1
On SW2 create two loopbacks and configure IP addresses as shown below.
- Loopback1: 192.168.8.8/24
- Loopback2: 192.168.88.8/24
- What kind of solution can solve the problem?
- What is a potential pitfall using this solution?
Lab Solution
Solution configuration can be accessed below; solution contains task 1 and task 2 (if you want to save it, click the link, then go to File-->Download):
https://drive.google.com/file/d/0BwE5C95tpjZOd29BZ3hqZVVSM28/edit?usp=sharing
Task 1
On SW2 create two loopbacks and configure IP addresses as shown below.
- Loopback1: 192.168.8.8/24
- Loopback2: 192.168.88.8/24
SW2 Configuration:
!
interface Loopback1
ip address 192.168.8.8 255.255.255.0
!
interface Loopback2
ip address 192.168.88.8 255.255.255.0
!
!
route-map CONN_TO_OSPF permit 10
match interface loopback1 loopback2
!
router ospf 1
no area 28 stub
area 28 nssa
redistribute connected subnets route-map CONN_TO_OSPF
!
In order to match the area a quick jump to R2.
R2 Config:
!
router ospf 1
no area 28 stub
area 28 nssa default-information-originate
!
Note!
R2 is ABR in area 28. While configuring NSSA area, ABR does NOT inject the default route by default. This way, all routers in area 28 (SW2) would not be able to reach other prefixes that area external ones redistributed in OSPF domain outside area 28. Thus, the area 28 nssa default-information-originate command on R2.
Pic. 2 - LSA Type 7 on SW2 (NSSA).
Pic. 3 - SW2 NSSA 7 Converted to LSA5 in Area 0.
Study Drill
OSPF Not-So-Stubby Area allows filtering LSA 5 but allows a presence of ASBR. The difference is that ASBR introduces external prefixes as LSA 7 (NSSA). ABR converts them into LSA 5 while introducing them into area 0.