OSPF Default Route Propagation Subcommand
| Router subcommand |
Description |
|---|---|
| default-information originate | Originates a type 5 LSA with a link ID of 0.0.0.0 only if the default route already exists in the routing table. |
| default-information originate always | Originates a type 5 LSA with a link ID of 0.0.0.0 regardless of whether the default route is in the routing table of the router |
Configuring OSPF Default Route Propagation
Pre-requisite: Open Shortest Path First (OSPF) protocol states
Default Route Propagation method supported by OSPF is to learn and redistribute default routes. OSPF requires that the router subcommand default-information originate, which essentially tells OSPF to redistribute default routes found in the routing table, either of the following :
- Static routes
- Routes from another routing protocol
Default routing feature when using default-information originate command with OSPF :
- Redistribution of any default route (0.0.0.0/0) in the routing table.
- Set the metric to cost 1 and the metric type to type E2 by default.
- OSPF also allows the use of the “always” keyword, which means that the default is sourced despite whether the default route is in the routing table or not.