Pic. 1 - Topology Diagram.
Task 1
On R1, R3, and R4 re-configure Frame-Relay and OSPF, so that there is no DR/BDR election needed on their serial0/0 links. The routers should use their default hello/dead timers 30/120 seconds respectively.
Task 2
On R2, advertise its loopback0 into OSPF area 0. Do not use network statement to accomplish that.
Task 3
Configure OSPF filtering on R4, so that 10.0.2.2/32 does not show in its routing table. Use ip prefix-list as you matching tool.
Questions
Task 2
On R2, advertise its loopback0 into OSPF area 0. Do not use network statement to accomplish that.
Task 3
Configure OSPF filtering on R4, so that 10.0.2.2/32 does not show in its routing table. Use ip prefix-list as you matching tool.
Questions
- What is the implication of having the same LSDB within the OSPF area?
- How can we filter LSAs within the area?
- How can we prevent a router from learning particular destinations located in the same area?
- What filtering tools does IOS give us to filter prefixes?
Lab Solution
Solution configuration below:
https://docs.google.com/file/d/0BwE5C95tpjZOOHRGZWd0VFhSM2M/edit?usp=sharing
Task 1
On R1, R3, and R4 re-configure Frame-Relay and OSPF, so that there is no DR/BDR election needed on their serial0/0 links. The routers should use their default hello/dead timers 30/120 seconds respectively.R1 Config:
!
interface Serial0/0
no ip ospf network point-to-multipoint non-broadcast
frame-relay map ip 172.16.0.4 104 broadcast
frame-relay map ip 172.16.0.3 103 broadcast
ip ospf network point-to-multipoint
!
router ospf 1
no neighbor 172.16.0.4
no neighbor 172.16.0.3
!
R3 Config:
!
interface Serial0/0
no ip ospf network point-to-multipoint non-broadcast
ip ospf network point-to-multipoint
frame-relay map ip 172.16.0.1 301 broadcast
!
R4 Config:
!
interface Serial0/0
no ip ospf network point-to-multipoint non-broadcast
ip ospf network point-to-multipoint
frame-relay map ip 172.16.0.1 401 broadcast !
Task 2
On R2, advertise its loopback0 into OSPF area 0. Do not use network statement to accomplish that.
R2 Config:
!
interface Loopback0
ip address 10.0.2.2 255.255.255.255
ip ospf 1 area 0
!
Task 3
Configure OSPF filtering on R4, so that 10.0.2.2/32 does not show in its routing table. Use ip prefix-list as your matching tool.
Task 2
On R2, advertise its loopback0 into OSPF area 0. Do not use network statement to accomplish that.
R2 Config:
!
interface Loopback0
ip address 10.0.2.2 255.255.255.255
ip ospf 1 area 0
!
Task 3
Configure OSPF filtering on R4, so that 10.0.2.2/32 does not show in its routing table. Use ip prefix-list as your matching tool.
Pic.2 - R4 Before Filtering.
Notice!
10.0.2.2/32 is present in the routing table.
R4 Config:
!
ip prefix-list BLOCK_R4_L0 deny 10.0.2.2/32
ip prefix-list BLOCK_R4_L0 permit 0.0.0.0/0 le 32
ip prefix-list BLOCK_R4_L0 permit 0.0.0.0/0 le 32
!
router ospf 1
distribute-list prefix BLOCK_R4_L0 in
!
Verification:
Pic. 3 - R4 After Filtering.
Pic. 4 - LSDB on R4 Contains LSA.
Study Drill
Within OSPF area, all routers share the same database information. LSA cannot be filter if it belongs to the same area. But we can filter what is going to be placed in the routing table. IP prefix-list is not the only one matching tool we could use here. Try to use other such as access-list or route-map to see if you can make it work.