IOS-XR /24 OSPF Loopback Advertisement

[ThomasCampbell64]

I am trying to advertise a loopback with a /24 subnet mask into OSPF however due to it's default behavior its still advertising it as a /32.

I have added "network point-to-point" under the interface but still see it showing as a /32 in the routing table.

What am I missing?

router ospf 1
router-id 1.1.1.1
auto-cost reference-bandwidth 19000
address-family ipv4 unicast
area 0
interface Loopback100
network point-to-point
!
interface GigabitEthernet0/0/0/3
!
!
!
end

[Cristian Matei · Accepted solution]

Hi,

    IOS-XR does not support changing the OSPF network-type for Loopback interface, so your configuration is ignored; you can check by issuing command "show ospf interface Loopback100"; this was actually a tweak on IOS-XE.

   On IOS-XR, if you want to advertise the Loopback with its original mask, you ned to globally, under OSPF process, configure Loopbacks as stub networks via command "loopback stub-network enabled"; from the RFC perspective, this is a cleaner and more logical way of doing it.

Best,

Cristian.

[Flavio Miranda]

@ThomasCampbell64 

Try to advisertise with redistribute connected

[Cristian Matei]

Hi,

   Redistribute connected, although resolves the challenge, should be avoided at all costs within MPLS environment for many reasons; even if this would be a pure IP environment, always use the solution which was designed to fix the problem, not a workaround like distribution which fixes the problem but brings other perks alongside.

Best,

Cristian.