OSPF over SVI

[NewComer]

Hello,

I'm experiencing an odd issue with my catalyst 6500. I have an SVI created running OSPF with cost 400. I have a second connection as a routed interface and not an SVI with identical configuration but cost 100. For some reason, no matter what I do, the SVI is prefered over the routed interface. See below.

I had an instance that the SVI far-end failed and traffic did not re-route to the second link and OSPF neighbor on the 6500 was in "init" state. The only way it failed over was when I shut the SVI manually. I now want to SVI, OSPF, make the routed interface the primary link but I'm unable without having to down the SVI. I read that BFD can be the solution but could not find anyone online that has used it to solve a similar problem as mine. Any help is much appreciated. 

SVI

interface TenGigabitEthernet1/3.1209
encapsulation dot1Q 1209
ip address x.x.x.x 255.255.255.252
ip ospf network point-to-point
ip ospf cost 400
ip ospf retransmit-interval 1

Routed Interface 

interface TenGigabitEthernet7/2
ip address x.x.x.x 255.255.255.252
ip ospf network point-to-point

ip ospf cost 100

ip ospf retransmit-interval 1

OSPF config on the 6500

router ospf 1
router-id x.x.x.x
log-adjacency-changes
auto-cost reference-bandwidth 10000
area 7 nssa default-information-originate
redistribute connected
passive-interface default
no passive-interface TenGigabitEthernet1/3.1209
no passive-interface TenGigabitEthernet7/2
network x.x.x.x 0.0.0.3 area 7
network x.x.x.x 0.0.0.3 area 7

[Giuseppe Larosa]

Hello NewComer,

the configurations that you have provided are both of routed interfaces.

The first one uses a subinterface in vlan 1209.

are these the new configuration ?

An SVI is a logical interface like

interface Vlan 1209

ip address x.x.x.x 255.255.255.252
ip ospf network point-to-point
ip ospf cost 400
ip ospf retransmit-interval 1

+

int tengiga 1/3

switchport

switchport trunk enc dot1q

swithcport mode trunk

switchport trunk allowed vlan 1209

!

However, when using SVI interface Vlan X type of interface you need to control what L2 ports are in L2 Vlan 1209 including all trunk ports.

if the Vlan 1209 is allowed in any trunk port, the SVI Vlan 1209 does not fall to up/down when the physical interface te1/3 goes down.

This is called autostate: the SVI is up/up if at least one L2 interface is up/up and in STP forwarding state for the corresponding Vlan.

In your case it is better to use routed interfaces.

About the fact that the router prefers routes learned on the link with higher local cost:

Your router is configured as an internal router in NSSA area 7 (unless you have omitted portions of OSPF confguration).

You should look at the OSPF database to understand what is happening.

Use show ip ospf database and more specific commands to see the details of received LSAs

Hope to help

Giuseppe