My Countingdown

Tuesday, December 13, 2011

Lab 6. OSPF Not So Stubby Area (NSSA)


  • Not So Stubby Area (NSSA) like stub area that no LSA type 4 and LSA type 5. The difference is in NSSA external route is still accepted.
  • Because in NSSA, LSA type 5 is rejected so external route change to LSA type 7 instead of LSA type 5.
  • NSSA need to be configured in all router within NSSA area


For topology and basic configuration, please refer to http://pursuingmydestiny.blogspot.com/2011/12/lab-3-ospf-standard-area.html

Let's add new loopback that will be advertised in RIP (saw as external route in OSPF).

R3#
interface Loopback1
 ip address 33.33.33.1 255.255.255.255
interface Loopback2
 ip address 33.33.33.2 255.255.255.255
interface Loopback3
 ip address 33.33.33.3 255.255.255.255

router rip
 version 2
 network 33.0.0.0
 no auto-summary

router ospf 3
 redistribute rip subnets

Then configure NSSA in area 1

R2(config-router)#router ospf 2
R2(config-router)#area 1 nssa

R3(config-router)#router ospf 3
R3(config-router)#area 1 nssa

Check the routing table in R3 and R1

R3(config-router)#do sh ip rou
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
O IA    1.1.1.1 [110/75] via 23.23.23.2, 00:01:41, FastEthernet0/0
     2.0.0.0/32 is subnetted, 1 subnets
O       2.2.2.2 [110/11] via 23.23.23.2, 00:01:41, FastEthernet0/0
     100.0.0.0/32 is subnetted, 3 subnets
O IA    100.100.100.1 [110/75] via 23.23.23.2, 00:01:41, FastEthernet0/0
O IA    100.100.100.2 [110/75] via 23.23.23.2, 00:01:41, FastEthernet0/0
O IA    100.100.100.3 [110/75] via 23.23.23.2, 00:01:41, FastEthernet0/0
     33.0.0.0/32 is subnetted, 3 subnets
C       33.33.33.1 is directly connected, Loopback1
C       33.33.33.3 is directly connected, Loopback3
C       33.33.33.2 is directly connected, Loopback2
     3.0.0.0/32 is subnetted, 1 subnets
C       3.3.3.3 is directly connected, Loopback0
     23.0.0.0/24 is subnetted, 1 subnets
C       23.23.23.0 is directly connected, FastEthernet0/0
     12.0.0.0/24 is subnetted, 1 subnets
O IA    12.12.12.0 [110/74] via 23.23.23.2, 00:01:44, FastEthernet0/0

R1(config)#do sh ip rout
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 12.12.12.2, 00:09:45, Serial0/0
     100.0.0.0/32 is subnetted, 7 subnets
C       100.100.100.4 is directly connected, Loopback4
C       100.100.100.5 is directly connected, Loopback5
C       100.100.100.6 is directly connected, Loopback6
C       100.100.100.7 is directly connected, Loopback7
C       100.100.100.1 is directly connected, Loopback1
C       100.100.100.2 is directly connected, Loopback2
C       100.100.100.3 is directly connected, Loopback3
     33.0.0.0/32 is subnetted, 3 subnets
O E2    33.33.33.1 [110/20] via 12.12.12.2, 00:01:05, Serial0/0
O E2    33.33.33.3 [110/20] via 12.12.12.2, 00:01:05, Serial0/0
O E2    33.33.33.2 [110/20] via 12.12.12.2, 00:01:05, Serial0/0
     3.0.0.0/32 is subnetted, 1 subnets
O IA    3.3.3.3 [110/75] via 12.12.12.2, 00:01:10, Serial0/0
     23.0.0.0/24 is subnetted, 1 subnets
O IA    23.23.23.0 [110/74] via 12.12.12.2, 00:01:10, Serial0/0
     12.0.0.0/24 is subnetted, 1 subnets
C       12.12.12.0 is directly connected, Serial0/0


Now we see external route RIP from R3 already in R1.
Check the ping from R1

R1(config)#do ping 33.33.33.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 33.33.33.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 28/46/68 ms

R1(config)#do ping 33.33.33.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 33.33.33.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 24/43/80 ms

R1(config)#do ping 33.33.33.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 33.33.33.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 28/44/76 ms

Now check ping from R3 to 100.100.100.4-100.100.100.7 that advertise from EIGRP in R1

R3(config)#do ping 100.100.100.4
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 100.100.100.4, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

R3(config)#do ping 100.100.100.5
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 100.100.100.5, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

It’s happen because no default route in R3 than it can not ping to those IPs. The solutin using command ‘default-information-originate’.

R2(config-router)#router ospf 2
R2(config-router)#area 1 nssa default-information-originate

Then check again routing table in R3

R3(config)#do sh ip rout
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 23.23.23.2 to network 0.0.0.0

     1.0.0.0/32 is subnetted, 1 subnets
O IA    1.1.1.1 [110/75] via 23.23.23.2, 00:06:57, FastEthernet0/0
     2.0.0.0/32 is subnetted, 1 subnets
O       2.2.2.2 [110/11] via 23.23.23.2, 00:06:57, FastEthernet0/0
     100.0.0.0/32 is subnetted, 3 subnets
O IA    100.100.100.1 [110/75] via 23.23.23.2, 00:06:57, FastEthernet0/0
O IA    100.100.100.2 [110/75] via 23.23.23.2, 00:06:57, FastEthernet0/0
O IA    100.100.100.3 [110/75] via 23.23.23.2, 00:06:57, FastEthernet0/0
     33.0.0.0/32 is subnetted, 3 subnets
C       33.33.33.1 is directly connected, Loopback1
C       33.33.33.3 is directly connected, Loopback3
C       33.33.33.2 is directly connected, Loopback2
     3.0.0.0/32 is subnetted, 1 subnets
C       3.3.3.3 is directly connected, Loopback0
     23.0.0.0/24 is subnetted, 1 subnets
C       23.23.23.0 is directly connected, FastEthernet0/0
     12.0.0.0/24 is subnetted, 1 subnets
O IA    12.12.12.0 [110/74] via 23.23.23.2, 00:07:01, FastEthernet0/0
O*N2 0.0.0.0/0 [110/1] via 23.23.23.2, 00:00:43, FastEthernet0/0

Now there is default route in R3. Let’s try ping again

R3(config)#do ping 100.100.100.4
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 100.100.100.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 24/37/60 ms

R3(config)#do ping 100.100.100.5
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 100.100.100.5, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 24/38/56 ms

R3(config)#do ping 100.100.100.6
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 100.100.100.6, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/47/88 ms

R3(config)#do ping 100.100.100.7
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 100.100.100.7, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/42/64 ms

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