Sunday, December 13, 2015

OSPF task #2. Multiple areas

Topology:


Use configuration from task OSPF #1 as initial configuration for this task.

Requirements: 

1. Configure OSPF area 3 to include the following: 
Link between R3 to R5. 
Link between R5 to R4.
Link between R2 to R4. 
Loopback0 interfaces of R4 and R5. 

2. Configure OSPF area 2 to include the following:
Link between R8 to R1.
Any configured and any future interfaces on R8. Use minimal number of commands to accomplish this. 

3. R8 should have connectivity to all devices included in this task, but the routing table should contain the minimal required amount of routing information. 

4. Traffic sourced or passing via R1, R2 or R8 towards loopback addresses of R4 and R5 should go via R2 (unless R2 fails, then go via R1). Do not alter OSPF link costs, or interface bandwidth to achieve this requirement. 

5. Routers R4 and R5 will be used in the future to redistribute routing information from other protocols into OSPF domain. Area 3 should use LSA type 7 to carry the redistributed routes information.

Solution: 

Highlight the text below to reveal the solution. 

In order to achieve requirement #2, on R8 use "network 0.0.0.0 255.255.255.255 area 2" under OSPF process configuration. 
Area 2 should be configured as totally stubby area to achieve requirement #3. 

In order to achieve requirement #4, on R3 summarize loopback addresses of R4 and R5. 

Area 3 should be configured as NSSA area to achieve requirement #5. 

R1:

!
router ospf 1
 router-id 10.0.1.1
 area 2 stub no-summary
 network 10.0.18.1 0.0.0.0 area 2
 neighbor 10.0.13.3
!

R2:


!
interface Ethernet1/0
 ip address 10.0.24.2 255.255.255.0
 ip ospf 1 area 3
!
router ospf 1
 router-id 10.0.2.2
 area 3 nssa
!

R3:


router ospf 1
 router-id 10.0.3.3
 area 0
  interface Loopback0
   network point-to-point
  !
  interface GigabitEthernet0/0/0/0
   authentication message-digest
   message-digest-key 1 md5 encrypted 122A31253D252B
   network non-broadcast
   priority 254
   neighbor 10.0.13.1
  !
  interface GigabitEthernet0/0/0/1
   authentication-key encrypted 0802606B282B
   authentication
   network broadcast
   priority 255
  !
 !
 area 3
  nssa
  range 10.0.4.0/23 advertise
  interface GigabitEthernet0/0/0/2
  !
 !
!

R4:


!
interface Ethernet0/0
 ip address 10.0.45.4 255.255.255.0
 ip ospf 1 area 3
!
interface Ethernet0/1
 ip address 10.0.24.4 255.255.255.0
 ip ospf 1 area 3
!
interface Loopback0
 ip address 10.0.4.4 255.255.255.255
 ip ospf network point-to-point
 ip ospf 1 area 3
!
router ospf 1
 area 3 nssa
!

R5:

!
router ospf 1
 area 3
  nssa
  interface Loopback0
   network point-to-point
  !
  interface GigabitEthernet0/0/0/1
  !
  interface GigabitEthernet0/0/0/2
  !
 !
!

R8:

!
router ospf 1
 router-id 10.0.8.8
 area 2 stub
 network 0.0.0.0 255.255.255.255 area 2
!


Verification:

R1#sh ip route ospf
Codes: L - local, 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, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is not set

      10.0.0.0/8 is variably subnetted, 17 subnets, 3 masks
O        10.0.2.2/32 [110/11] via 10.0.12.2, 00:25:16, Ethernet0/1
O        10.0.3.3/32 [110/11] via 10.0.13.3, 00:25:16, Ethernet0/0
O IA     10.0.4.0/23 [110/31] via 10.0.13.3, 00:17:39, Ethernet0/0
O IA     10.0.4.4/32 [110/21] via 10.0.12.2, 00:16:36, Ethernet0/1
O IA     10.0.5.5/32 [110/31] via 10.0.12.2, 00:16:36, Ethernet0/1
O        10.0.8.8/32 [110/11] via 10.0.18.8, 00:24:53, Ethernet1/0
O        10.0.23.0/24 [110/20] via 10.0.13.3, 00:25:16, Ethernet0/0
                      [110/20] via 10.0.12.2, 00:25:16, Ethernet0/1
O IA     10.0.24.0/24 [110/20] via 10.0.12.2, 00:17:12, Ethernet0/1
O IA     10.0.35.0/24 [110/20] via 10.0.13.3, 00:20:46, Ethernet0/0
O IA     10.0.45.0/24 [110/30] via 10.0.13.3, 00:20:41, Ethernet0/0
                      [110/30] via 10.0.12.2, 00:16:36, Ethernet0/1


R1#traceroute 10.0.5.5 sou
R1#traceroute 10.0.5.5 source 10.0.1.1
Type escape sequence to abort.
Tracing the route to 10.0.5.5
VRF info: (vrf in name/id, vrf out name/id)
  1 10.0.12.2 4 msec 1 msec 4 msec
  2 10.0.24.4 4 msec 5 msec 5 msec
  3 10.0.45.5 1 msec *  2 msec

R8#sh ip route
Codes: L - local, 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, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is 10.0.18.1 to network 0.0.0.0

O*IA  0.0.0.0/0 [110/11] via 10.0.18.1, 00:26:07, Ethernet0/0
      10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
C        10.0.8.8/32 is directly connected, Loopback0
C        10.0.18.0/24 is directly connected, Ethernet0/0
L        10.0.18.8/32 is directly connected, Ethernet0/0



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