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OSPF route vs static route

jamie-nicol
Level 1
Level 1

Hi all,

Please see attached diagram for clarity.

 

i have a multipod environment (2 pods).

 

in each pod, i use a static default route to a local firewall, and leaf switches in each pod send default traffic to the local exit point, as you'd expect.

 

if i then use OSPF to advertise the default route, from the Pod2 firewall, and then delete the static route in Pod2, the OSPF border leaf prefers the OSPF route (which is good). However, all other leaves in pod2 prefer the static route learned from pod1!

i'd expect the Pod2 leafs to follow the OSPF route learned from Pod2.

 

any idea why this is, and how i can get the Pod2 leafs to prefer the route learned from Pod2?

Routing metrics are:

 

Border leaf (Pod2):   0.0.0.0/0, ubest/mbest: 1/0 via 10.x.x.x, vlan14, [110/1], 20:25:54, ospf-default, type-2

 

Other leaf (Pod2):   0.0.0.0/0, ubest/mbest: 2/0 *via 10.x.x.x%overlay-1, [110/0], 00:00:48, bgp-65111, internal, tag 65111 recursive next hop: 10.x.x.x/32%overlay-1  (this is via a leaf in Pod1 which has a static default route)

 

I suspect the highlighted metrics are playing a part, but i don't know how to manipulate these.

If i introduced OSPF in Pod1, would the metrics then be equal in each pod, and behave as we'd expect?

 

TIA for any help.

1 Reply 1

joezersk
Cisco Employee
Cisco Employee

I suspect you did not add your POD2 spines to be route-reflectors under the ACI system settings (if using later ACI versions), or under Fabric >  Fabric Policies (if using older ACI versions).

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