What Does BDR Mean in 200-301?
Full form: Backup Designated Router
Also known as: Backup Designated Router
Quick Definition
The OSPF router elected to take over as DR if the current DR fails.
Full Definition
The BDR is the second router elected in an OSPF multi-access network. It monitors the DR and takes over its role instantly if the DR fails, preventing a full re-election and minimising convergence time. The BDR also has full adjacency with all DROTHER routers and receives all LSAs. Routers that are neither DR nor BDR are called DROTHER routers.
Exam Trap — Don't Get Fooled
DROTHER routers (non-DR, non-BDR) form adjacency only with the DR and BDR — not with each other. Their neighbour state with other DROTHERs stays at 2-Way, not Full.
Related 200-301 Terms
Frequently Asked Questions
What does BDR mean on the 200-301 exam?
The BDR is the second router elected in an OSPF multi-access network. It monitors the DR and takes over its role instantly if the DR fails, preventing a full re-election and minimising convergence time. The BDR also has full adjacency with all DROTHER routers and receives all LSAs. Routers that are neither DR nor BDR are called DROTHER routers.
How does BDR appear as a trap on the 200-301?
DROTHER routers (non-DR, non-BDR) form adjacency only with the DR and BDR — not with each other. Their neighbour state with other DROTHERs stays at 2-Way, not Full.
How important is BDR on the 200-301 exam?
BDR falls under the Routing domain of the 200-301 exam. Understanding it in context with related terms like dr and ospf is essential for answering scenario-based questions correctly.