Re: OSPF route between Nexus7010 and ASR 1004

Informatica El Corte Ingles Informatica El Corte Ingles · ‎02-05-2014

I cannot receive any OSPF route from Nexus 7010 to ASR1004 even they are both OSPF neighbour. I have attached the config for both, Please can you have a look and advise.Both Nexus and ASR part of Area2.

NEXUS 7010

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router ospf CORE

vrf 1

router-id 172.31.254.14

rfc1583compatibility

interface loopback1

ip router ospf CORE area 0.0.0.1

interface Ethernet1/1.134

ip router ospf CORE area 0.0.0.1

interface Ethernet1/2.135

ip router ospf CORE area 0.0.0.1

interface Ethernet1/3.136

ip router ospf CORE area 0.0.0.1

interface Ethernet1/4.137

ip router ospf CORE area 0.0.0.1

interface Ethernet1/5.138

ip router ospf CORE area 0.0.0.1

interface Ethernet1/7.140

ip router ospf CORE area 0.0.0.2

interface Ethernet1/7.140

ip router ospf CORE area 0.0.0.2

interface loopback1

description OSPF ISP_2

ip address 172.31.254.14/32

ip router ospf CORE area 0.0.0.1

NK7_MUR2-ISP_2# sh ip ospf neighbors vrf 1

OSPF Process ID CORE VRF 1

Total number of neighbors: 6

Neighbor ID Pri State Up Time Address Interface

172.31.254.5 1 FULL/BDR 00:33:58 10.36.0.118 Eth1/1.134

172.31.254.3 1 FULL/DR 00:33:56 10.36.0.122 Eth1/2.135

172.31.254.6 1 FULL/DR 00:34:01 10.36.0.126 Eth1/3.136

172.31.254.4 1 FULL/DR 00:33:54 10.36.0.130 Eth1/4.137

172.31.254.13 1 FULL/DR 00:34:00 10.36.0.133 Eth1/5.138

172.31.254.16 1 FULL/BDR 00:34:01 10.36.0.142 Eth1/7.140

ASR 1004

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router ospf 2

router-id 172.31.254.16

network 10.36.0.140 0.0.0.3 area 2

network 172.31.254.16 0.0.0.0 area 2

interface Loopback1

ip address 10.31.254.16 255.255.255.255

interface TenGigabitEthernet0/0/0.140

description Conexion VDC ISP2 1/7.140

encapsulation dot1Q 140

ip address 10.36.0.142 255.255.255.252

ASR_2#sh ip ospf neighbor

Neighbor ID Pri State Dead Time Address Interface

172.31.254.14 1 FULL/DR 00:00:38 10.36.0.141 TenGigabitEthernet0/0/0.140

ASR_2#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

a - application route

+ - replicated route, % - next hop override

Gateway of last resort is not set

Rolf Fischer · ‎02-05-2014

Hi,

bienvenido a CSC ;-)

Ethernet1/7.140 seems to be the only link in Area 2 on the Nexus.

Does it have any active interfaces in the Backbone Area too?

Otherwise it will not act as an ABR between Area 1 and 2; so perhaps a Virtual Link will be needed to connect the Area 2 link to the backbone if it has to be Area 2 for this connection.

What does 'show ip ospf database' show on the ASR?

HTH

Rolf

Informatica El Corte Ingles Informatica El Corte Ingles · ‎02-06-2014

I guess it would not have to create the virtual link because there physical connection between the Nexus and backboone

The nexus has multiple interfaces in area 1:

interface loopback1

ip router ospf CORE area 0.0.0.1

interface Ethernet1/1.134

ip router ospf CORE area 0.0.0.1

interface Ethernet1/2.135

ip router ospf CORE area 0.0.0.1

interface Ethernet1/3.136

ip router ospf CORE area 0.0.0.1

interface Ethernet1/4.137

ip router ospf CORE area 0.0.0.1

interface Ethernet1/5.138

ip router ospf CORE area 0.0.0.1

ASR_2#sh ip ospf database

OSPF Router with ID (172.31.254.16) (Process ID 2)

Router Link States (Area 2)

Link ID         ADV Router      Age         Seq#       Checksum Link count
172.31.254.14   172.31.254.14   1777        0x80000072 0x00D9DB 1
172.31.254.16   172.31.254.16   2015        0x80000027 0x004698 1

Net Link States (Area 2)

Link ID ADV Router Age Seq# Checksum
10.36.0.141 172.31.254.14 1777 0x8000002B 0x00F0F9

Rolf Fischer · ‎02-06-2014

The problem is that you have two non-backbone Areas (1 and 2) but no interface in Area 0, so the Nexus is not an Area Border Router. You can check that with 'show ip ospf border-router' on the ASR.

As you can see, the Link State Database shows only the single link in Area 2 (2 Router-LSAs and the corresponing Network-LSA), nothing more (originated from other Areas).

If the new link has to be in Area 2, you will have to connect it somehow to Area 0; this is an OSPF requirement.

Useful Link: OSPF Design Guide

HTH

Rolf

OSPF Design Guide

Informatica El Corte Ingles Informatica El Corte Ingles · ‎02-06-2014

Hi Dimitri,

The issue has been solved.

We have configured the virtual link between routers and everything works fine.

Thank you very much.

Regards