03-09-2020 07:40 AM - last edited on 05-26-2022 02:23 AM by Translator
Hello,
I think I have a strange bahavior. I have a 4500X VSS connected to two Nexus 3064 like this:
The Nexus are getting their 0.0.0.0/0 from Area 0 and are able to forward traffic in and out. But the 4500x does not get a 0.0.0.0/0 route in his routing-table.
A
show ip ospf 3080 database external
on the 4500x shows that a default-route is advertised(I think):
OSPF Router with ID (3.0.8.26) (Process ID 3080) Type-5 AS External Link States LS age: 890 Options: (No TOS-capability, No DC, Upward) LS Type: AS External Link Link State ID: 0.0.0.0 (External Network Number ) Advertising Router: 3.0.8.11 LS Seq Number: 80000123 Checksum: 0x1088 Length: 36 Network Mask: /0 Metric Type: 2 (Larger than any link state path) MTID: 0 Metric: 1 Forward Address: 0.0.0.0 External Route Tag: 0 LS age: 705 Options: (No TOS-capability, No DC, Upward) LS Type: AS External Link Link State ID: 0.0.0.0 (External Network Number ) Advertising Router: 3.0.8.12 LS Seq Number: 80000123 Checksum: 0xA8D Length: 36 Network Mask: /0 Metric Type: 2 (Larger than any link state path) MTID: 0 Metric: 1 Forward Address: 0.0.0.0 External Route Tag: 0
"3.0.8.11" and "3.0.8.12" are routers in area 0 (other site).
On the Nexus the 0.0.0.0/0 is part of the routing table:
rz1-nx3k# sh ip route vrf Printer | head IP Route Table for VRF "Printer" '*' denotes best ucast next-hop '**' denotes best mcast next-hop '[x/y]' denotes [preference/metric] '%<string>' in via output denotes VRF <string> 0.0.0.0/0, ubest/mbest: 1/0 *via 172.31.31.94, Vlan1008, [110/1], 5d03h, ospf-3080, type-2
The ospf-process is configured with
default-information originate.
All routers are ospf-neighbors. But I don'T get a default-route on the 4500X.
Any Ideas?
Kind regards,
Andreas
Solved! Go to Solution.
03-13-2020 09:51 AM
Hello,
I was able to update the 4500x to Version 03.08.07.E , the exact same Version as on the other 4500x.
But no luck - still no default-route:
BS1#sh ip route vrf Printer Load for five secs: 8%/0%; one minute: 8%; five minutes: 8% Time source is NTP, 17:46:47.180 UTC Fri Mar 13 2020 Routing Table: Printer 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 a - application route + - replicated route, % - next hop override Gateway of last resort is not set 172.30.0.0/16 is variably subnetted, 5 subnets, 2 masks O 172.30.64.148/30 [110/41] via 172.30.64.157, 21:42:05, Vlan2316 [110/41] via 172.30.64.153, 21:42:05, Vlan2315 C 172.30.64.152/30 is directly connected, Vlan2315 L 172.30.64.154/32 is directly connected, Vlan2315 C 172.30.64.156/30 is directly connected, Vlan2316 L 172.30.64.158/32 is directly connected, Vlan2316 BS1#
BS1#sh ip ospf 3080 rib 0.0.0.0 Load for five secs: 10%/1%; one minute: 9%; five minutes: 8% Time source is NTP, 17:48:24.827 UTC Fri Mar 13 2020 %OSPF: Route not in OSPF Base Topology (MTID 0) local RIB BS1#
but:
BS1#sh ip ospf 3080 database external Load for five secs: 8%/0%; one minute: 8%; five minutes: 8% Time source is NTP, 17:49:42.799 UTC Fri Mar 13 2020 OSPF Router with ID (3.0.8.26) (Process ID 3080) Type-5 AS External Link States LS age: 1263 Options: (No TOS-capability, No DC, Upward) LS Type: AS External Link Link State ID: 0.0.0.0 (External Network Number ) Advertising Router: 3.0.8.11 LS Seq Number: 800001E5 Checksum: 0x8A4B Length: 36 Network Mask: /0 Metric Type: 2 (Larger than any link state path) MTID: 0 Metric: 1 Forward Address: 0.0.0.0 External Route Tag: 0 LS age: 1081 Options: (No TOS-capability, No DC, Upward) LS Type: AS External Link Link State ID: 0.0.0.0 (External Network Number ) Advertising Router: 3.0.8.12 LS Seq Number: 800001E5 Checksum: 0x8450 Length: 36 Network Mask: /0 Metric Type: 2 (Larger than any link state path) MTID: 0 Metric: 1 Forward Address: 0.0.0.0 External Route Tag: 0 BS1#
Hmm? I have no idea (except the Nexus?)...
Kind regards,
Andreas
03-13-2020 10:22 AM - last edited on 05-26-2022 02:51 AM by Translator
Hi,
One last thing. Post the following output from both 4500x devices:
show ip ospf 3080 database asbr-summary
show ip ospf 3080 border-routers
show ip OSPF 3080 database external 0.0.0.0
show ip ospf 3080 rib 0.0.0.0
show ip route vrf Printer ospf
Regards,
Cristian Matei.
03-13-2020 10:50 AM
Hi,
ok here is the output of the two 4500X. The BS1-011 has some more routes due to more neighbors, I had to cut them out due to privacy:
BS1#show ip ospf 3080 database asbr-summary Load for five secs: 10%/0%; one minute: 8%; five minutes: 8% Time source is NTP, 18:26:27.132 UTC Fri Mar 13 2020 OSPF Router with ID (3.0.8.26) (Process ID 3080) Summary ASB Link States (Area 26) Adv Router is not-reachable in topology Base with MTID 0 LS age: 1656 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.11 (AS Boundary Router address) Advertising Router: 3.0.8.15 LS Seq Number: 80000098 Checksum: 0xB58E Length: 28 Network Mask: /0 MTID: 0 Metric: 80 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1637 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.11 (AS Boundary Router address) Advertising Router: 3.0.8.16 LS Seq Number: 80000098 Checksum: 0x41D9 Length: 28 Network Mask: /0 MTID: 0 Metric: 120 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1658 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.12 (AS Boundary Router address) Advertising Router: 3.0.8.15 LS Seq Number: 80000098 Checksum: 0x1A51 Length: 28 Network Mask: /0 MTID: 0 Metric: 40 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1640 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.12 (AS Boundary Router address) Advertising Router: 3.0.8.16 LS Seq Number: 80000098 Checksum: 0xA59C Length: 28 Network Mask: /0 MTID: 0 Metric: 80 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1660 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.13 (AS Boundary Router address) Advertising Router: 3.0.8.15 LS Seq Number: 80000098 Checksum: 0xA1A0 Length: 28 Network Mask: /0 MTID: 0 Metric: 80 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1642 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.13 (AS Boundary Router address) Advertising Router: 3.0.8.16 LS Seq Number: 80000098 Checksum: 0xA5F Length: 28 Network Mask: /0 MTID: 0 Metric: 40 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1663 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.14 (AS Boundary Router address) Advertising Router: 3.0.8.15 LS Seq Number: 80000098 Checksum: 0x29EF Length: 28 Network Mask: /0 MTID: 0 Metric: 120 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1644 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.14 (AS Boundary Router address) Advertising Router: 3.0.8.16 LS Seq Number: 80000098 Checksum: 0x91AE Length: 28 Network Mask: /0 MTID: 0 Metric: 80 BS1#show ip ospf 3080 border-routers Load for five secs: 8%/0%; one minute: 8%; five minutes: 8% Time source is NTP, 18:26:53.538 UTC Fri Mar 13 2020 OSPF Router with ID (3.0.8.26) (Process ID 3080) Base Topology (MTID 0) Internal Router Routing Table Codes: i - Intra-area route, I - Inter-area route i 3.0.8.15 [1] via 172.30.64.157, Vlan2316, ABR, Area 26, SPF 3 i 3.0.8.16 [1] via 172.30.64.153, Vlan2315, ABR, Area 26, SPF 3 BS1#show ip ospf 3080 database external 0.0.0.0 Load for five secs: 8%/1%; one minute: 8%; five minutes: 8% Time source is NTP, 18:27:14.647 UTC Fri Mar 13 2020 OSPF Router with ID (3.0.8.26) (Process ID 3080) Type-5 AS External Link States LS age: 1692 Options: (No TOS-capability, No DC, Upward) LS Type: AS External Link Link State ID: 0.0.0.0 (External Network Number ) Advertising Router: 3.0.8.11 LS Seq Number: 800001E6 Checksum: 0x884C Length: 36 Network Mask: /0 Metric Type: 2 (Larger than any link state path) MTID: 0 Metric: 1 Forward Address: 0.0.0.0 External Route Tag: 0 LS age: 1510 Options: (No TOS-capability, No DC, Upward) LS Type: AS External Link Link State ID: 0.0.0.0 (External Network Number ) Advertising Router: 3.0.8.12 LS Seq Number: 800001E6 Checksum: 0x8251 Length: 36 Network Mask: /0 Metric Type: 2 (Larger than any link state path) MTID: 0 Metric: 1 Forward Address: 0.0.0.0 External Route Tag: 0 BS1#show ip ospf 3080 rib 0.0.0.0 Load for five secs: 8%/0%; one minute: 8%; five minutes: 8% Time source is NTP, 18:27:30.298 UTC Fri Mar 13 2020 %OSPF: Route not in OSPF Base Topology (MTID 0) local RIB BS1#show ip route vrf Printer ospf Load for five secs: 8%/0%; one minute: 8%; five minutes: 8% Time source is NTP, 18:27:57.612 UTC Fri Mar 13 2020 Routing Table: Printer 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 a - application route + - replicated route, % - next hop override Gateway of last resort is not set 172.30.0.0/16 is variably subnetted, 5 subnets, 2 masks O 172.30.64.148/30 [110/41] via 172.30.64.157, 22:23:16, Vlan2316 [110/41] via 172.30.64.153, 22:23:16, Vlan2315 BS1#
BS1-011#show ip ospf 3080 database asbr-summary Load for five secs: 12%/1%; one minute: 10%; five minutes: 10% Time source is NTP, 18:34:05.416 UTC Fri Mar 13 2020 OSPF Router with ID (3.0.8.1) (Process ID 3080) Summary ASB Link States (Area 24) Adv Router is not-reachable in topology Base with MTID 0 LS age: 1478 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.13 (AS Boundary Router address) Advertising Router: 3.0.8.11 LS Seq Number: 800001C3 Checksum: 0x60B9 Length: 28 Network Mask: /0 MTID: 0 Metric: 80 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1797 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.13 (AS Boundary Router address) Advertising Router: 3.0.8.12 LS Seq Number: 800001BB Checksum: 0xFBFC Length: 28 Network Mask: /0 MTID: 0 Metric: 120 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1479 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.14 (AS Boundary Router address) Advertising Router: 3.0.8.11 LS Seq Number: 800001C4 Checksum: 0xC27D Length: 28 Network Mask: /0 MTID: 0 Metric: 40 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1480 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.14 (AS Boundary Router address) Advertising Router: 3.0.8.12 LS Seq Number: 800001C2 Checksum: 0x52C6 Length: 28 Network Mask: /0 MTID: 0 Metric: 80 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1652 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.15 (AS Boundary Router address) Advertising Router: 3.0.8.11 LS Seq Number: 800001BA Checksum: 0x5EC2 Length: 28 Network Mask: /0 MTID: 0 Metric: 80 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1661 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.15 (AS Boundary Router address) Advertising Router: 3.0.8.12 LS Seq Number: 800001BA Checksum: 0xC681 Length: 28 Network Mask: /0 MTID: 0 Metric: 40 Adv Router is not-reachable in topology Base with MTID 0 LS age: 380 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.16 (AS Boundary Router address) Advertising Router: 3.0.8.11 LS Seq Number: 800001B9 Checksum: 0xE711 Length: 28 Network Mask: /0 MTID: 0 Metric: 120 Adv Router is not-reachable in topology Base with MTID 0 LS age: 390 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.16 (AS Boundary Router address) Advertising Router: 3.0.8.12 LS Seq Number: 800001B9 Checksum: 0x50CF Length: 28 Network Mask: /0 MTID: 0 Metric: 80 BS1-011#show ip ospf 3080 border-routers Load for five secs: 10%/1%; one minute: 10%; five minutes: 10% Time source is NTP, 18:34:25.712 UTC Fri Mar 13 2020 OSPF Router with ID (3.0.8.1) (Process ID 3080) Base Topology (MTID 0) Internal Router Routing Table Codes: i - Intra-area route, I - Inter-area route i 3.0.8.11 [1] via 172.30.31.81, Vlan2385, ABR/ASBR, Area 24, SPF 14 i 3.0.8.12 [1] via 172.30.31.85, Vlan2386, ABR/ASBR, Area 24, SPF 14 BS1-011#show ip ospf 3080 database external 0.0.0.0 Load for five secs: 12%/1%; one minute: 10%; five minutes: 10% Time source is NTP, 18:40:03.822 UTC Fri Mar 13 2020 OSPF Router with ID (3.0.8.1) (Process ID 3080) Type-5 AS External Link States LS age: 616 Options: (No TOS-capability, No DC, Upward) LS Type: AS External Link Link State ID: 0.0.0.0 (External Network Number ) Advertising Router: 3.0.8.11 LS Seq Number: 800001E7 Checksum: 0x864D Length: 36 Network Mask: /0 Metric Type: 2 (Larger than any link state path) MTID: 0 Metric: 1 Forward Address: 0.0.0.0 External Route Tag: 0 LS age: 433 Options: (No TOS-capability, No DC, Upward) LS Type: AS External Link Link State ID: 0.0.0.0 (External Network Number ) Advertising Router: 3.0.8.12 LS Seq Number: 800001E7 Checksum: 0x8052 Length: 36 Network Mask: /0 Metric Type: 2 (Larger than any link state path) MTID: 0 Metric: 1 Forward Address: 0.0.0.0 External Route Tag: 0 BS1-011#show ip ospf 3080 rib 0.0.0.0 Load for five secs: 11%/0%; one minute: 10%; five minutes: 10% Time source is NTP, 18:34:48.752 UTC Fri Mar 13 2020 OSPF Router with ID (3.0.8.1) (Process ID 3080) Base Topology (MTID 0) OSPF local RIB Codes: * - Best, > - Installed in global RIB LSA: type/LSID/originator *> 0.0.0.0/0, Ext2, cost 1, tag 0 SPF Instance 111, age 1w1d, fwd cost 1 Flags: RIB via 172.30.31.85, Vlan2386 Flags: RIB LSA: 5/0.0.0.0/3.0.8.12 via 172.30.31.81, Vlan2385 Flags: RIB LSA: 5/0.0.0.0/3.0.8.11 BS1-011#show ip route vrf Printer ospf Load for five secs: 11%/1%; one minute: 11%; five minutes: 10% Time source is NTP, 18:35:15.168 UTC Fri Mar 13 2020 Routing Table: Printer 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 a - application route + - replicated route, % - next hop override Gateway of last resort is 172.30.31.85 to network 0.0.0.0 O*E2 0.0.0.0/0 [110/1] via 172.30.31.85, 1w1d, Vlan2386 [110/1] via 172.30.31.81, 1w1d, Vlan2385 172.30.0.0/16 is variably subnetted, 18 subnets, 2 masks O 172.30.31.88/30 [110/41] via 172.30.31.81, 1w1d, Vlan2385 O 172.30.31.92/30 [110/41] via 172.30.31.85, 1w1d, Vlan2386 O 172.30.31.96/30 [110/41] via 172.30.31.81, 1w1d, Vlan2385 O 172.30.31.100/30 [110/41] via 172.30.31.85, 1w1d, Vlan2386 O 172.30.31.104/30 [110/41] via 172.30.31.81, 1w1d, Vlan2385 O 172.30.31.108/30 [110/41] via 172.30.31.85, 1w1d, Vlan2386 O 172.30.31.112/30 [110/41] via 172.30.31.81, 1w1d, Vlan2385 O 172.30.31.116/30 [110/41] via 172.30.31.85, 1w1d, Vlan2386 O 172.30.31.120/30 [110/41] via 172.30.31.81, 1w1d, Vlan2385 O 172.30.31.124/30 [110/41] via 172.30.31.85, 1w1d, Vlan2386 O 172.30.33.112/30 [110/41] via 172.30.31.85, 1w1d, Vlan2386 O 172.30.33.116/30 [110/41] via 172.30.31.81, 1w1d, Vlan2385 O 172.30.33.124/30 [110/41] via 172.30.31.81, 1w1d, Vlan2385 O 172.30.35.28/30 [110/41] via 172.30.31.85, 1w1d, Vlan2386 [110/41] via 172.30.31.81, 1w1d, Vlan2385 BS1-011#
Kind regards,
Andreas
03-13-2020 11:52 AM - last edited on 05-26-2022 02:52 AM by Translator
Hi,
I would open a TAC case as i'm certain there is something buggy, as there is no need for
capability vrf-lite
(it works on on 4K, on the other not), and both 4K's see their directly attached ABR's as "not reachable in the graph of nodes" from the Type4 LSA (one validates it though, BS11, the other one not, BS1).
Regards,
Cristian Matei.
03-15-2020 05:36 AM - last edited on 05-26-2022 02:54 AM by Translator
Hi,
I was curious about what @paul driver wrote about the
capability vrf lite
command, and found this explanation(https://community.cisco.com/t5/routing/where-to-configure-the-quot-capability-vrf-lite-quot-on-ce-or-pe/td-p/2812305) from @Peter Paluch . It sounds like that the command
capabilty vrf lite
is needed by design, if OSPF is used in conjunction with multiple vrf's.
I think my scenario is exactly what Peter described: R1 (VRF) --- Link in Area 1 --- R2 --- Link in Area 0 --- R3
except that in my case all routers are "holding" the same vrf (Printer). But seems it doesn't matter. The 4500X always acts as a ABR if running OSPF in conjunction with vrf.
Why this being the case that the other 4500X(BS1-011) does not need the
capability vrf lite
command? Could it be the circumstance that is directly connected to the router with the (static) configured route to 0.0.0.0/0. ?
Or I'm totally wrong?
Kind regards,
Andreas
03-15-2020 08:44 AM - last edited on 05-26-2022 02:56 AM by Translator
Hi,
OSPF always amazes me, and there is always one corner case when something interesting comes up. Are you willing to do one more test? Configure the Nexus devices, directly attached in the same area as BS1, to inject a default route into OSPF (make sure it does, if necessary use the always keyword), and on the BS1:
show ip ospf 3080 database external 0.0.0.0, show ip ospf asbr-sumamry, show ip ospf rib 0.0.0.0, show ip route vrf Printer ospf.
Regards,
Cristian Matei.
03-15-2020 09:10 AM - last edited on 05-26-2022 02:57 AM by Translator
Hi,
sure! I had to use the "always" parameter to get the
default-route
into the table of the 4500X(BS1). But this causes traffic to the "Printer-Network" be black-holed if sourced from another site. So I configured this only for a few seconds...
Here is the output:
BS1#show ip ospf 3080 database external 0.0.0.0 Load for five secs: 9%/0%; one minute: 8%; five minutes: 8% Time source is NTP, 16:59:10.629 UTC Sun Mar 15 2020 OSPF Router with ID (3.0.8.26) (Process ID 3080) Type-5 AS External Link States LS age: 1549 Options: (No TOS-capability, No DC, Upward) LS Type: AS External Link Link State ID: 0.0.0.0 (External Network Number ) Advertising Router: 3.0.8.11 LS Seq Number: 80000242 Checksum: 0xCEA9 Length: 36 Network Mask: /0 Metric Type: 2 (Larger than any link state path) MTID: 0 Metric: 1 Forward Address: 0.0.0.0 External Route Tag: 0 LS age: 1370 Options: (No TOS-capability, No DC, Upward) LS Type: AS External Link Link State ID: 0.0.0.0 (External Network Number ) Advertising Router: 3.0.8.12 LS Seq Number: 80000242 Checksum: 0xC8AE Length: 36 Network Mask: /0 Metric Type: 2 (Larger than any link state path) MTID: 0 Metric: 1 Forward Address: 0.0.0.0 External Route Tag: 0 LS age: 113 Options: (No TOS-capability, No DC, Upward) LS Type: AS External Link Link State ID: 0.0.0.0 (External Network Number ) Advertising Router: 3.0.8.15 LS Seq Number: 80000002 Checksum: 0x3D79 Length: 36 Network Mask: /0 Metric Type: 2 (Larger than any link state path) MTID: 0 Metric: 1 Forward Address: 0.0.0.0 External Route Tag: 0 BS1# BS1#show ip ospf 3080 database asbr-summary Load for five secs: 11%/1%; one minute: 8%; five minutes: 8% Time source is NTP, 17:00:39.590 UTC Sun Mar 15 2020 OSPF Router with ID (3.0.8.26) (Process ID 3080) Summary ASB Link States (Area 26) Adv Router is not-reachable in topology Base with MTID 0 LS age: 1633 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.11 (AS Boundary Router address) Advertising Router: 3.0.8.15 LS Seq Number: 800000F4 Checksum: 0xFCEA Length: 28 Network Mask: /0 MTID: 0 Metric: 80 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1613 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.11 (AS Boundary Router address) Advertising Router: 3.0.8.16 LS Seq Number: 800000F4 Checksum: 0x8836 Length: 28 Network Mask: /0 MTID: 0 Metric: 120 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1635 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.12 (AS Boundary Router address) Advertising Router: 3.0.8.15 LS Seq Number: 800000F4 Checksum: 0x61AD Length: 28 Network Mask: /0 MTID: 0 Metric: 40 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1617 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.12 (AS Boundary Router address) Advertising Router: 3.0.8.16 LS Seq Number: 800000F4 Checksum: 0xECF8 Length: 28 Network Mask: /0 MTID: 0 Metric: 80 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1638 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.13 (AS Boundary Router address) Advertising Router: 3.0.8.15 LS Seq Number: 800000F4 Checksum: 0xE8FC Length: 28 Network Mask: /0 MTID: 0 Metric: 80 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1619 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.13 (AS Boundary Router address) Advertising Router: 3.0.8.16 LS Seq Number: 800000F4 Checksum: 0x51BB Length: 28 Network Mask: /0 MTID: 0 Metric: 40 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1641 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.14 (AS Boundary Router address) Advertising Router: 3.0.8.15 LS Seq Number: 800000F4 Checksum: 0x704C Length: 28 Network Mask: /0 MTID: 0 Metric: 120 Adv Router is not-reachable in topology Base with MTID 0 LS age: 1622 Options: (No TOS-capability, No DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.0.8.14 (AS Boundary Router address) Advertising Router: 3.0.8.16 LS Seq Number: 800000F4 Checksum: 0xD80B Length: 28 Network Mask: /0 MTID: 0 Metric: 80 BS1# BS1#show ip ospf 3080 rib 0.0.0.0 Load for five secs: 9%/1%; one minute: 8%; five minutes: 8% Time source is NTP, 17:01:38.993 UTC Sun Mar 15 2020 OSPF Router with ID (3.0.8.26) (Process ID 3080) Base Topology (MTID 0) OSPF local RIB Codes: * - Best, > - Installed in global RIB LSA: type/LSID/originator *> 0.0.0.0/0, Ext2, cost 1, tag 0 SPF Instance 17, age 00:04:18, fwd cost 1 Flags: RIB, PartialSPF via 172.30.64.157, Vlan2316 Flags: RIB LSA: 5/0.0.0.0/3.0.8.15 BS1# BS1#show ip route vrf Printer ospf Load for five secs: 10%/1%; one minute: 8%; five minutes: 8% Time source is NTP, 17:02:07.161 UTC Sun Mar 15 2020 Routing Table: Printer 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 a - application route + - replicated route, % - next hop override Gateway of last resort is 172.30.64.157 to network 0.0.0.0 O*E2 0.0.0.0/0 [110/1] via 172.30.64.157, 00:04:47, Vlan2316 172.30.0.0/16 is variably subnetted, 5 subnets, 2 masks O 172.30.64.148/30 [110/41] via 172.30.64.157, 00:11:26, Vlan2316 [110/41] via 172.30.64.153, 00:11:26, Vlan2315 BS1#
Kind regards,
Andreas
03-16-2020 01:49 PM - last edited on 05-26-2022 02:59 AM by Translator
Hi,
To keep it simple, yes, in your case the
capability vrf-lite
is needed, per this design only on BS1, but i would add it also on BS11, in case the ASBR's which will do the
default-route
injection are gonna change, which may end you up with BS11 not having the default route anymore; so play safe and put it on both sides. Now as for the explanation:
1. OSPF must accept all received LSA's as long as it's not a malformed packet, by OSPF design
2. Per OSPF design with all areas attached to area 0 via ABR's, it means that an ABR should never receive a Type5 LSA inbound on a non-area 0 adjacency (like on area 26) from an OSPF RID which is not attached in that area (26), as this would mean either a discontiguous area 0 or an invalid design such as area0------area26-----areax. BS1 and BS11 behave as ABR's, due to the VRF functionality and inherent connection to the super backbone(super area 0). BS11 sees/receives the Type5 LSA as injected by a router directly attached in the area and it validates it (design is ok, cause BS11 says i'm ABR and i have a neighbor in area xx which is also an ASBR, all good). BS1 sees/receives the Type5 LSA as injected by a router NOT directly attached in the area and it does NOT validate it(design is not ok, cause it's like BS1 is an ABR , attached to another ABR the nexus, which is attached to another area where the ASBR's are residing, which is not possible, to have 2 further areas beyond area 0); the same mechanism for validation happens for Type4 LSA's, that's why it was showing up as "Advertised Router is not reachable", as this is OSPF saying there is something wrong in this design, i can't include that RID in the graph of nodes, it's not reachable per OSPF design
3. One more reason to have "capability vrf lite" is that without it, both BS1 and BS11 will not validate Type5 LSA's injected by routers not attached to their area, which means any redistribution performed on the routers which are attached only to area 0.
Regards,
Cristian Matei.
03-17-2020 12:55 AM - last edited on 05-26-2022 03:00 AM by Translator
Hi Cristian,
thank's a lot for the detailed explanation. One thing, if I implement this scenario in the default vrf, the
default-route
is always available on all routers, regardless of the location and without the
capability vrf-lite
command.
Kind regards,
Andreas
03-17-2020 01:15 AM
Hi,
Correct, because if the router does not run OSPF in a VRF, it does not think its connected to the Super Area 0, thus does not behave as an ABR, thus it does not perform checks as an ABR.
Regards,
Cristian Matei.
03-17-2020 01:54 AM
Hi,
yes, I just want to verify - for my understanding.
Kind regards,
Andreas
03-10-2020 06:42 AM - last edited on 05-26-2022 03:01 AM by Translator
By default using default information originate command too an OSPF will not send a default route to a network .
Use the below command to do it.
Router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#ip route 0.0.0.0 0.0.0.0 192.168.1.2
Router(config)#router ospf 100
Router(config-router)#default-information originate metric 10 metric-type 1
Router(config-router)#exit
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