ospf terms...

read em and weep... from ocg, p. 143

Link state database 


The data structure held by an OSPF router for the purpose of storing topology data.


Shortest Path First (SPF) 

The name of the algorithm OSPF uses to analyze the LSDB. The analysis determines the best (lowest cost) route for each prefix/length.

Link State Update (LSU)

The name of the OSPF packet that holds the detailed topology information, specifically LSAs


Link State Advertisement (LSA)

The name of a class of OSPF data structures that hold topology information. LSAs are held in memory in the LSDB and communicated over the network in LSU messages.

Area


A contiguous grouping of routers and router interfaces. Routers in an area strive to learn all topology information about the area, but they do not learn topology information about areas to which they do not connect.

Area Border Router (ABR)


A router that has interfaces connected to at least two diferent OSPF areas, including the backbone area. ABRs hold topology data for each area, and calculate routes for each area, and advertise about those routes between areas.

Backbone router

Any router that has at least one interface connected to the backbone area.

Internal routers


A router that has interfaces connected to only one area, making the router completely internal to that one area.

Designated Router (DR)


On multiaccess data links like LANs, an OSPF router elected by the routers on that data link to perform special functions. These functions include the generation of LSAs representing the subnet, and playing a key role in the data-
base exchange process.

Backup Designated Router (BDR)


A router on a multiaccess data link that monitors the DR
and becomes prepared to take over for the DR, should the
DR fail.