topic Re: How to implement SHARED route policy in NSO? in NSO Developer Hub Discussions

How to implement SHARED route policy in NSO?

Elvin J — Tue, 08 Oct 2024 13:29:21 GMT

Hi, I want to create one shared route policy that multiple services can use. With my current implementation, this shared policy gets rewritten every time, which is not what I want. I want it to be extended with each request instead. Even if I can manage shared RPL to be extended , I think the other connected services will get out of sync. Do you have any ideas or suggestions on how to do this?

Re: How to implement SHARED route policy in NSO?

snovello — Tue, 08 Oct 2024 14:31:41 GMT

The issue here is you are probaly using the IOS-XR CLI NED that models a route policy as a name and a single leaf with the policy definition. If the policy definition has a structure and different services for example can add a 'match' in the policy, then the way to do this is to have a service dedicated to managing the route policy. You model that service as you need, for exampl with a leaf-list of matches. The create callback of your services goes through the list of matches and build the required policy string.

Then the services that require a match to be added, specify that match in the template by adding a match under the service that manages the route policy. That's an example of the stacked services pattern, where the template of a service is specifying what it's intent is, in terms of a lower level service.

Re: How to implement SHARED route policy in NSO?

Elvin J — Wed, 09 Oct 2024 07:04:27 GMT

Thanks for the answer, could you please show example code?

Re: How to implement SHARED route policy in NSO?

snovello — Fri, 11 Oct 2024 07:18:51 GMT

After some conversation with Elvin, we now have this small NSO example package.

https://github.com/StefanoNovello/shared-route-policy/