Forwarding address (FA) in OSPF LSAs

In scenarios where we have multiple ABRs converting/translating same network from Type7 to Type5 LSA, then OSPF database need to act on only one of them. The other must withdraw its LSA. This is one of many loop avoidance techniques adopted in OSPF. The RFC 2328 says “if two routers, both reachable from one another, … Continue reading Forwarding address (FA) in OSPF LSAs

Default route (0.0.0.0/0) LSA Types in different OSPF areas

As we already know OSPF has different area types (normal, stub, totally stub, not-so-stubby/nssa and nssa totally stub) and the LSAs permitted inside them varies accordingly. In OSPF the default-route is treated differently. By default OSPF does not allow a default-route from any other domain to be advertised/redistributed into its domain. We need to configure … Continue reading Default route (0.0.0.0/0) LSA Types in different OSPF areas