SD-WAN

Brian K Berry - I found this bit of information.

OSPF routes are only redistributed into BGP if the OSPF routes are selected, and vice versa. And the static route distance is one of the keys when you create the static route, the other being the prefix. You can increase the distance for a given static route to insure that for that prefix, routes from other protocols are preferred over the static route.

John Peterson may have more/better info for you.

Brian K Berry from my understanding, ""use learned routes"" would be the correct type of service-route when you want the router to defer to it's RIB (which may be populated with routes from OSPF, BGP, static, etc.).

I believe ""routing stack"" is for directing packets into the routing engine itself, i.e. for protocol processing. I think the primary utility there is for BGP over SVR, to have packets containing BGP messages land on the BGP stack. David M Bond can keep me honest here.

Reid L Stidolph Brian K Berry 

So by default a router will use ""learned routes"" e.g. bgp, ospf, static, connected, etc if no service route is given. If a service route is given it will use the next-hops given in said service route. By having a service route the conductor auto generates some peer service routes on other routers to route traffic to this node. With this in mind `use learned routes` on a service route is the same as the default use but it also allows the conductor to generate the peer service routes. Without said `use learned routes` the local router would have have fib entries for the bgp routes but other routers not connected to the bgp network would not have a fib entry for the bgp routes.

Bgp over svr is a bit of a separate subject than this. It fills some of the same features in that if you have a few 128T routers and you use bgp peering between them any of the routes exchanged between them will be svred. If using bgp over svr however there is no need to use a `use learned routes` as any routes redistrubted into bgp will be seen on all routers you bgp over svr peer with.

Now as for `routing stack` the easy answer is there is no need to use it. I believe we are going to hide that from the UI. But yes it is something used in the internal implementation of bgp over svr and it sends received frames to the routing stack.

Follow-up question to David M Bond - regarding this statement from above:

""if you have a few 128T routers and you use bgp peering between them any of the routes exchanged between them will be svred. If using bgp over svr however there is no need to use a `use learned routes` as any routes redistrubted into bgp will be seen on all routers you bgp over svr peer with.""

So does this mean that since BGP routes will be SVR-ed to a 128T peer, will the peer service route be auto-generated, without the 'use learned routes' service route?

So in the configuration for bgp over svr there are no peer service routes for the bgp prefixes received being auto-generated . The traffic is svred without the need of peer service routes in the config. When a bgp route is received through bgp over svr we dynamically create a fib entry that will svr to said peer without a peer service route and without the need for use-learned-routes.