NSSA
Friday, November 14, 2008
NSSA --- NOT SO STUBBY AREA : AN NSSA PROVIDES A MECHANISM FOR ASBR'S ATTACHED TO A STUB AREA (NON-BACKBONE) STUB AREA TO PROPOGATE EXTERNAL ROUTES (TYPE 7 LSA'S ) INTO THE ROUTING DOMAIN..
configuration **** one thing to remember is that both sides should be configured unlike the tsa..the stub flags for nssa should be agreed by both of the routers
now we will use redistribute connected subnets --- remember we still dint advertise l20 on r3 ..now using this it will flag it as a n2 route..
CODE
r2(config)#router ospf 1
r2(config-router)#area 23 nssa
OSPF: Area is configured as stub area already ---------------------------> first remove the stub area config on r3 using no version of that
r2(config-router)#
r2(config-router)#area 23 nssa
OSPF: Area is configured as stub area already ---------------------------> first remove the stub area config on r3 using no version of that
r2(config-router)#
CODE
r3#config
Configuring from terminal, memory, or network [terminal]? t
Enter configuration commands, one per line. End with CNTL/Z.
r3(config)#router ospf 1
r3(config-router)#no area 23 stub
r3(config-router)#area
*Mar 1 01:28:20.359: %OSPF-5-ADJCHG: Process 1, Nbr 10.1.2.1 on Serial2/1 from FULL to DOWN, Neighbor Down: Adjacency forced to reset
r3(config-router)#area 23 nssa
r3(config-router)#
*Mar 1 01:28:25.363: %OSPF-5-ADJCHG: Process 1, Nbr 10.1.2.1 on Serial2/1 from DOWN to DOWN, Neighbor Down: Adjacency forced to reset
r3(config-router)#
as#2
[Resuming connection 2 to r2 ... ]
r2(config-router)#area 23 nssa
OSPF: Area is configured as stub area already
r2(config-router)#no area 23 stub
r2(config-router)#area
*Mar 1 01:28:46.467: %OSPF-5-ADJCHG: Process 1, Nbr 172.20.200.1 on Serial2/1 from FULL to DOWN, Neighbor Down: Adjacency forced to reset
r2(config-router)#area 23 nssa
r2(config-router)#
*Mar 1 01:28:50.551: %OSPF-5-ADJCHG: Process 1, Nbr 172.20.200.1 on Serial2/1 from DOWN to DOWN, Neighbor Down: Adjacency forced to reset
r2(config-router)#
*Mar 1 01:28:58.403: %OSPF-5-ADJCHG: Process 1, Nbr 172.20.200.1 on Serial2/1 from LOADING to FULL, Loading Done
r2(config-router)#
Configuring from terminal, memory, or network [terminal]? t
Enter configuration commands, one per line. End with CNTL/Z.
r3(config)#router ospf 1
r3(config-router)#no area 23 stub
r3(config-router)#area
*Mar 1 01:28:20.359: %OSPF-5-ADJCHG: Process 1, Nbr 10.1.2.1 on Serial2/1 from FULL to DOWN, Neighbor Down: Adjacency forced to reset
r3(config-router)#area 23 nssa
r3(config-router)#
*Mar 1 01:28:25.363: %OSPF-5-ADJCHG: Process 1, Nbr 10.1.2.1 on Serial2/1 from DOWN to DOWN, Neighbor Down: Adjacency forced to reset
r3(config-router)#
as#2
[Resuming connection 2 to r2 ... ]
r2(config-router)#area 23 nssa
OSPF: Area is configured as stub area already
r2(config-router)#no area 23 stub
r2(config-router)#area
*Mar 1 01:28:46.467: %OSPF-5-ADJCHG: Process 1, Nbr 172.20.200.1 on Serial2/1 from FULL to DOWN, Neighbor Down: Adjacency forced to reset
r2(config-router)#area 23 nssa
r2(config-router)#
*Mar 1 01:28:50.551: %OSPF-5-ADJCHG: Process 1, Nbr 172.20.200.1 on Serial2/1 from DOWN to DOWN, Neighbor Down: Adjacency forced to reset
r2(config-router)#
*Mar 1 01:28:58.403: %OSPF-5-ADJCHG: Process 1, Nbr 172.20.200.1 on Serial2/1 from LOADING to FULL, Loading Done
r2(config-router)#
see the ip route table
CODE
r3#sir
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
172.20.0.0/24 is subnetted, 1 subnets
C 172.20.200.0 is directly connected, Loopback20
10.0.0.0/24 is subnetted, 5 subnets
O IA 10.1.12.0 [110/128] via 10.1.23.1, 00:00:36, Serial2/1
C 10.1.3.0 is directly connected, Loopback3
O 10.1.2.0 [110/65] via 10.1.23.1, 00:00:36, Serial2/1
O IA 10.1.1.0 [110/129] via 10.1.23.1, 00:00:36, Serial2/1
C 10.1.23.0 is directly connected, Serial2/1
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
172.20.0.0/24 is subnetted, 1 subnets
C 172.20.200.0 is directly connected, Loopback20
10.0.0.0/24 is subnetted, 5 subnets
O IA 10.1.12.0 [110/128] via 10.1.23.1, 00:00:36, Serial2/1
C 10.1.3.0 is directly connected, Loopback3
O 10.1.2.0 [110/65] via 10.1.23.1, 00:00:36, Serial2/1
O IA 10.1.1.0 [110/129] via 10.1.23.1, 00:00:36, Serial2/1
C 10.1.23.0 is directly connected, Serial2/1
CODE
r3#
*Mar 1 01:29:41.883: %SYS-5-CONFIG_I: Configured from console by console
r3#siod
OSPF Router with ID (172.20.200.1) (Process ID 1)
Router Link States (Area 23)
Link ID ADV Router Age Seq# Checksum Link count
10.1.2.1 10.1.2.1 47 0x8000000D 0x00ED97 3
172.20.200.1 172.20.200.1 46 0x8000000D 0x0019EE 3
Summary Net Link States (Area 23)
Link ID ADV Router Age Seq# Checksum
10.1.1.0 10.1.2.1 50 0x80000002 0x00A931
10.1.12.0 10.1.2.1 50 0x80000002 0x0026AA
r3#
*Mar 1 01:29:41.883: %SYS-5-CONFIG_I: Configured from console by console
r3#siod
OSPF Router with ID (172.20.200.1) (Process ID 1)
Router Link States (Area 23)
Link ID ADV Router Age Seq# Checksum Link count
10.1.2.1 10.1.2.1 47 0x8000000D 0x00ED97 3
172.20.200.1 172.20.200.1 46 0x8000000D 0x0019EE 3
Summary Net Link States (Area 23)
Link ID ADV Router Age Seq# Checksum
10.1.1.0 10.1.2.1 50 0x80000002 0x00A931
10.1.12.0 10.1.2.1 50 0x80000002 0x0026AA
r3#
CODE
now use redistribute connected to advertise loopback20
[code]r3(config)#router ospf 1
r3(config-router)#redi
r3(config-router)#redistribute con
r3(config-router)#redistribute connected sub
r3(config-router)#redistribute connected subnets
r3(config-router)#end
r3#
*Mar 1 01:30:36.647: %SYS-5-CONFIG_I: Configured from console by console
r3#sir
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
172.20.0.0/24 is subnetted, 1 subnets
C 172.20.200.0 is directly connected, Loopback20
10.0.0.0/24 is subnetted, 5 subnets
O IA 10.1.12.0 [110/128] via 10.1.23.1, 00:01:33, Serial2/1
C 10.1.3.0 is directly connected, Loopback3
O 10.1.2.0 [110/65] via 10.1.23.1, 00:01:33, Serial2/1
O IA 10.1.1.0 [110/129] via 10.1.23.1, 00:01:33, Serial2/1
C 10.1.23.0 is directly connected, Serial2/1
r3#
as#2
[Resuming connection 2 to r2 ... ]
r2#sir
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
172.20.0.0/24 is subnetted, 1 subnets
O N2 172.20.200.0 [110/20] via 10.1.23.2, 00:00:09, Serial2/1 ------------------------type 7 on abr
10.0.0.0/24 is subnetted, 5 subnets
C 10.1.12.0 is directly connected, Serial2/0
O 10.1.3.0 [110/65] via 10.1.23.2, 00:01:36, Serial2/1
C 10.1.2.0 is directly connected, Loopback2
O 10.1.1.0 [110/65] via 10.1.12.1, 00:01:46, Serial2/0
C 10.1.23.0 is directly connected, Serial2/1
r2#
as#1
[Resuming connection 1 to r1 ... ]
r1#sir
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
172.20.0.0/24 is subnetted, 1 subnets
O E2 172.20.200.0 [110/20] via 10.1.12.2, 00:00:14, Serial2/0 ------------------> converted to type 5 by abr
10.0.0.0/24 is subnetted, 5 subnets
C 10.1.12.0 is directly connected, Serial2/0
O IA 10.1.3.0 [110/129] via 10.1.12.2, 00:01:41, Serial2/0
O IA 10.1.2.0 [110/65] via 10.1.12.2, 00:01:50, Serial2/0
C 10.1.1.0 is directly connected, Loopback1
O IA 10.1.23.0 [110/128] via 10.1.12.2, 00:01:50, Serial2/0
r1#
[code]r3(config)#router ospf 1
r3(config-router)#redi
r3(config-router)#redistribute con
r3(config-router)#redistribute connected sub
r3(config-router)#redistribute connected subnets
r3(config-router)#end
r3#
*Mar 1 01:30:36.647: %SYS-5-CONFIG_I: Configured from console by console
r3#sir
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
172.20.0.0/24 is subnetted, 1 subnets
C 172.20.200.0 is directly connected, Loopback20
10.0.0.0/24 is subnetted, 5 subnets
O IA 10.1.12.0 [110/128] via 10.1.23.1, 00:01:33, Serial2/1
C 10.1.3.0 is directly connected, Loopback3
O 10.1.2.0 [110/65] via 10.1.23.1, 00:01:33, Serial2/1
O IA 10.1.1.0 [110/129] via 10.1.23.1, 00:01:33, Serial2/1
C 10.1.23.0 is directly connected, Serial2/1
r3#
as#2
[Resuming connection 2 to r2 ... ]
r2#sir
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
172.20.0.0/24 is subnetted, 1 subnets
O N2 172.20.200.0 [110/20] via 10.1.23.2, 00:00:09, Serial2/1 ------------------------type 7 on abr
10.0.0.0/24 is subnetted, 5 subnets
C 10.1.12.0 is directly connected, Serial2/0
O 10.1.3.0 [110/65] via 10.1.23.2, 00:01:36, Serial2/1
C 10.1.2.0 is directly connected, Loopback2
O 10.1.1.0 [110/65] via 10.1.12.1, 00:01:46, Serial2/0
C 10.1.23.0 is directly connected, Serial2/1
r2#
as#1
[Resuming connection 1 to r1 ... ]
r1#sir
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
172.20.0.0/24 is subnetted, 1 subnets
O E2 172.20.200.0 [110/20] via 10.1.12.2, 00:00:14, Serial2/0 ------------------> converted to type 5 by abr
10.0.0.0/24 is subnetted, 5 subnets
C 10.1.12.0 is directly connected, Serial2/0
O IA 10.1.3.0 [110/129] via 10.1.12.2, 00:01:41, Serial2/0
O IA 10.1.2.0 [110/65] via 10.1.12.2, 00:01:50, Serial2/0
C 10.1.1.0 is directly connected, Loopback1
O IA 10.1.23.0 [110/128] via 10.1.12.2, 00:01:50, Serial2/0
r1#
CODE
r2#siod
OSPF Router with ID (10.1.2.1) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
10.1.1.1 10.1.1.1 726 0x80000008 0x004EDA 3
10.1.2.1 10.1.2.1 176 0x80000008 0x0080C0 2
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.1.2.0 10.1.2.1 1650 0x80000003 0x0074AA
10.1.3.0 10.1.2.1 161 0x80000001 0x00EFEF
10.1.23.0 10.1.2.1 1650 0x80000003 0x0005C5
Router Link States (Area 23)
Link ID ADV Router Age Seq# Checksum Link count
10.1.2.1 10.1.2.1 168 0x8000000D 0x00ED97 3
172.20.200.1 172.20.200.1 169 0x8000000D 0x0019EE 3
Summary Net Link States (Area 23)
Link ID ADV Router Age Seq# Checksum
10.1.1.0 10.1.2.1 171 0x80000002 0x00A931
10.1.12.0 10.1.2.1 172 0x80000002 0x0026AA
Type-7 AS External Link States (Area 23) ---------------------------------------> see this
Link ID ADV Router Age Seq# Checksum Tag
172.20.200.0 172.20.200.1 76 0x80000001 0x0076FC 0
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.20.200.0 10.1.2.1 75 0x80000001 0x00CA2F 0
r2#
OSPF Router with ID (10.1.2.1) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
10.1.1.1 10.1.1.1 726 0x80000008 0x004EDA 3
10.1.2.1 10.1.2.1 176 0x80000008 0x0080C0 2
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.1.2.0 10.1.2.1 1650 0x80000003 0x0074AA
10.1.3.0 10.1.2.1 161 0x80000001 0x00EFEF
10.1.23.0 10.1.2.1 1650 0x80000003 0x0005C5
Router Link States (Area 23)
Link ID ADV Router Age Seq# Checksum Link count
10.1.2.1 10.1.2.1 168 0x8000000D 0x00ED97 3
172.20.200.1 172.20.200.1 169 0x8000000D 0x0019EE 3
Summary Net Link States (Area 23)
Link ID ADV Router Age Seq# Checksum
10.1.1.0 10.1.2.1 171 0x80000002 0x00A931
10.1.12.0 10.1.2.1 172 0x80000002 0x0026AA
Type-7 AS External Link States (Area 23) ---------------------------------------> see this
Link ID ADV Router Age Seq# Checksum Tag
172.20.200.0 172.20.200.1 76 0x80000001 0x0076FC 0
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.20.200.0 10.1.2.1 75 0x80000001 0x00CA2F 0
r2#