7b - OSPF Concepts Flashcards
What is Link State?
A routing protocol that uses an SPF algorithm with an LSDB to compute routes.
What is the OSPF metric?
OSPF totals the cost associated with each interface in the end-to-end route, with the cost based on link bandwidth.
When is a 2-way state reached?
- Once routers have agreed to be neighbors* Both routers reach a 2-way state with each other, it means that both routers meet all OSPF configuration requirements to become neighbors. Effectively, at that point, they are neighbors, and ready to exchange their LSDB with each other.
When is a full state reached?
After the routers have completed the exchange of LSUs and the LSDB exchange has been completed.
What is an ABR
Area Border Router - a router with interfaces connected to the backbone area and at least one other area.
What is a Backbone Router
A router connected to the backbone area including ABRs.
What is a Internal Router
A router with all interfaces within a single area but not the backbone area.
What is an Area
A set of routers and links that share the same LSDB information, but not with routers in other areas for efficiency.
What is the Backbone Area
Area 0. A special area to which all other areas must connect.
What is an Intra-area Route?
A route to a subnet inside the same area as the router.
What is an Inter-area Route?
A route to a subnet in an area of which the router is not a part.
What is a DR?
Designated Router - a router on a shared link like Ethernet to which all the other routers - DROther - exchange database information. The DR router makes sure the other routers on the shared link get a copy of each LSA.
What is a BDR?
Backup Designated Router. Takes over the DR duties if the DR fails.
What is a DROther?
Routers on a shared link that are NOT DR or BDR. They sync with the DR but not with each other. DROther routers never go beyond 2-way state with each other.
What is Fully Adjacent?
In OSPF, a characterization of the state of a neighbor in which the two neighbors have reached the full state.
