In OSPF, the DR and BDR elected in a broadcast network listen to both the 224.0.0.5 address and the 224.0.0.6 address.

Question

Options

• ATRUE
• BFALSE
• C
• D

• A
  77% (41)
• B
  4% (2)
• C
  13% (7)
• D
  6% (3)

Explanation

In OSPF broadcast networks, the DR and BDR listen on 224.0.0.5 (AllSPFRouters) because they are OSPF routers like all others, AND on 224.0.0.6 (AllDRouters) because they hold the special DR/BDR roles that require receiving updates sent directly to the designated routers. Regular DROther routers only join 224.0.0.5 and send their LSAs to 224.0.0.6 - meaning only the DR/BDR will process them, which reduces flooding overhead on the segment. Option B is wrong because it incorrectly implies the DR/BDR skip one of these addresses; they must listen to both to function correctly. Memory tip: Think "D and B get Both" - the DR and BDR listen to Both multicast groups (224.0.0.5 and 224.0.0.6), while plain DROther routers only get one.

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