12-05-2003 10:56 AM - edited 03-02-2019 12:10 PM
I am having trouble advertising a default route from an NSSA ASBR to the ABR, and then subsequently getting the NSSA ABR to propagate that default route to the OSPF domain. The NSSA is connect to area 0 w/ a virtual link. I have tried different versions of routers/code to no avail. The farthest I have been able to get is configuring area x nssa default-information originate along w/ a static default route on the NSSA ASBR. Sometimes the NSSA ABR will show an N2 in the routing table. It would appear the the P-bit is not set because the default route never gets propagated. I'm able to get the external default route propagated if I connect it to an ABR directly.
12-05-2003 12:44 PM
Have you also included the "default-information-originate" in the area nssa command of the NSSA ABR, as well as the NSSA ASBR?
Also, I'm not sure why the ABR will only show the N2 sometimes. Is the route also going down in the ASBR at the same time it goes down in the ABR? Does the Type 7 LSA come and go from the OSPF database?
HTH
Mark
12-05-2003 02:37 PM
This should work. The only problem I can think of is the virtual link not being established properly.
Couls you provide us with the following for the NSSA ABR:
sh ip ospf virt
sh ip ospf da nssa
sh ip ospf da ext
sh ip ospf
Thanks,
12-08-2003 12:45 PM
Router r5 is the NSSA ABR for area 5, and R6 is the NSSA ASBR for area 6. Here are the routing tables for R5 and R6 as well as the output you requested.
r5#r ho show ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
U - per-user static route, o - ODR
T - traffic engineered route
Gateway of last resort is 10.5.1.2 to network 0.0.0.0
10.0.0.0/8 is variably subnetted, 10 subnets, 4 masks
O 10.0.10.0/24 [110/65] via 10.3.1.9, 00:25:42, Serial0
C 10.3.1.8/29 is directly connected, Serial0
O 10.3.1.9/32 [110/64] via 10.3.1.9, 3d02h, Serial0
O IA 10.2.10.0/24 [110/138] via 10.3.1.9, 00:25:42, Serial0
O 10.3.1.10/32 [110/128] via 10.3.1.9, 3d02h, Serial0
O IA 10.4.10.0/24 [110/138] via 10.3.1.9, 00:25:42, Serial0
O 10.3.1.0/30 [110/128] via 10.3.1.9, 3d02h, Serial0
C 10.5.1.0/30 is directly connected, ATM0
O IA 10.6.1.24/29 [110/129] via 10.3.1.9, 00:22:51, Serial0
C 10.1.254.4/32 is directly connected, Loopback0
O*N2 0.0.0.0/0 [110/1] via 10.5.1.2, 00:04:08, ATM0
r5#
r6#show ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, 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 172.16.1.2 to network 0.0.0.0
172.16.0.0/24 is subnetted, 1 subnets
C 172.16.1.0 is directly connected, Ethernet0
10.0.0.0/8 is variably subnetted, 7 subnets, 5 masks
O IA 10.0.10.0/24 [110/130] via 10.5.1.1, 00:26:10, ATM0
O IA 10.2.10.0/24 [110/203] via 10.5.1.1, 3d04h, ATM0
O IA 10.4.10.0/24 [110/203] via 10.5.1.1, 3d03h, ATM0
O IA 10.3.0.0/16 [110/193] via 10.5.1.1, 3d04h, ATM0
C 10.5.1.0/30 is directly connected, ATM0
O IA 10.6.1.24/29 [110/194] via 10.5.1.1, 00:23:15, ATM0
C 10.1.254.5/32 is directly connected, Loopback0
S* 0.0.0.0/0 [1/0] via 172.16.1.2
r6#
r6#show ip ospf virt
r6#show ip ospf da nssa
OSPF Router with ID (10.1.254.5) (Process ID 1)
Type-7 AS External Link States (Area 5)
LS age: 1496
Options: (No TOS-capability, No Type 7/5 translation, DC)
LS Type: AS External Link
Link State ID: 0.0.0.0 (External Network Number )
Advertising Router: 10.1.254.4
LS Seq Number: 80000090
Checksum: 0x7A99
Length: 36
Network Mask: /0
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 1
Forward Address: 0.0.0.0
External Route Tag: 0
--More-- LS age: 1617
Options: (No TOS-capability, Type 7/5 translation, DC)
LS Type: AS External Link
Link State ID: 0.0.0.0 (External Network Number )
Advertising Router: 10.1.254.5
LS Seq Number: 80000001
Checksum: 0x1B7F
Length: 36
Network Mask: /0
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 1
Forward Address: 0.0.0.0
External Route Tag: 0
r6#show ip ospf da nssa ext
OSPF Router with ID (10.1.254.5) (Process ID 1)
r6#show ip ospf
Routing Process "ospf 1" with ID 10.1.254.5
Supports only single TOS(TOS0) routes
Supports opaque LSA
It is an autonomous system boundary router
Redistributing External Routes from,
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
Number of external LSA 0. Checksum Sum 0x0
Number of opaque AS LSA 0. Checksum Sum 0x0
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 1. 0 normal 0 stub 1 nssa
External flood list length 0
Area 5
Number of interfaces in this area is 1
It is a NSSA area
generates NSSA default route with cost 1
Area has no authentication
SPF algorithm executed 46 times
Area ranges are
Number of LSA 10. Checksum Sum 0x60734
Number of opaque link LSA 0. Checksum Sum 0x0
Number of DCbitless LSA 0
--More-- Number of indication LSA 0
Number of DoNotAge LSA 0
Flood list length 0
T_SERV#5
[Resuming connection 2 to r5 ... ]
r5#show ip ospf virt
Virtual Link OSPF_VL0 to router 10.1.254.1 is up
Run as demand circuit
DoNotAge LSA allowed.
Transit area 3, via interface Serial0, Cost of using 64
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:00
Adjacency State FULL (Hello suppressed)
Message digest authentication enabled
No key configured, using default key id 0
r5#show ip ospf da nssa
OSPF Router with ID (10.1.254.4) (Process ID 1)
Type-7 AS External Link States (Area 5)
LS age: 1572
Options: (No TOS-capability, No Type 7/5 translation, DC)
LS Type: AS External Link
Link State ID: 0.0.0.0 (External Network Number )
Advertising Router: 10.1.254.4
LS Seq Number: 80000090
Checksum: 0x7A99
Length: 36
Network Mask: /0
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 1
Forward Address: 0.0.0.0
External Route Tag: 0
--More-- Routing Bit Set on this LSA
LS age: 1695
Options: (No TOS-capability, Type 7/5 translation, DC)
LS Type: AS External Link
Link State ID: 0.0.0.0 (External Network Number )
Advertising Router: 10.1.254.5
LS Seq Number: 80000001
Checksum: 0x1B7F
Length: 36
Network Mask: /0
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 1
Forward Address: 0.0.0.0
External Route Tag: 0
r5#show ip osp f da ext
OSPF Router with ID (10.1.254.4) (Process ID 1)
r5#show ip ospf
Routing Process "ospf 1" with ID 10.1.254.4
Supports only single TOS(TOS0) routes
It is an area border router
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
Number of external LSA 0. Checksum Sum 0x0
Number of DCbitless external LSA 0
Number of DoNotAge external LSA 0
Number of areas in this router is 3. 2 normal 0 stub 1 nssa
Area BACKBONE(0)
Number of interfaces in this area is 1
Area has message digest authentication
SPF algorithm executed 38 times
Area ranges are
Number of LSA 17. Checksum Sum 0x69E54
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 13
Area 3
Number of interfaces in this area is 1
Area has message digest authentication
SPF algorithm executed 32 times
Area ranges are
--More-- 10.3.0.0/16 Active(128) Advertise
Number of LSA 27. Checksum Sum 0xBAECF
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 0
Area 5
Number of interfaces in this area is 1
It is a NSSA area
Perform type-7/type-5 LSA translation
generates NSSA default route with cost 1
Area has no authentication
SPF algorithm executed 56 times
Area ranges are
Number of LSA 16. Checksum Sum 0x97857
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 0
r5#
12-08-2003 06:14 PM
Both R5 and R6 are advertising a type 7 LSA. From what I understand R6 is the ASBR and only it should be advertising the type 7. Could you post the ospf config for R5.
BTW: Can you see any of the routes from area 5 in area 0 and the rest of the AS?
12-09-2003 10:32 AM
I figured it out...must be bug related. I am studying for the RS IE, and am using older 3810s. Once I replaced the configuration w/ 2600 and 3600 routers, it worked.
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide