Hi jonashauge / spuluka,
From your feedback it's look like the Cobranet is totally cannot run under Layer 3. My Campus Design Building A connect to Buuilding B using OSPF (physical interface). Both of building have Cobranet device. It's look like i need to redesign back my network due to this hell Cobranet. In the initial design this Cobranet not say anything regarding their limitation software. After all the network already live this issue come and Cobranet said the network design should follow their limitation not they follow the network design.
It's look like i need to change the Layer 3 using vlan (OSPF) instead of using physical. Beside of that i'm still hope if someone have an idea how to solve this without i'm need to change my network design.
Thanks