A router LSA is shown in the figure, which of the following statements is wrong?

Question

Options

• AThe Router ID of this router is 10.0.12.1
• BThis router is the DR
• CThis router has established an adjacency relationship
• DThis router supports the import of external routes

• A
  9% (4)
• B
  82% (37)
• C
  7% (3)
• D
  2% (1)

Explanation

Option B is the wrong statement because Router LSAs (Type 1) do not contain any bit or field indicating DR (Designated Router) status. DR status is conveyed by the Network LSA (Type 2), which is generated by the DR itself - if a router originates a Network LSA, that signals it is the DR, not its Router LSA.

Why the other options are correct (and therefore not the answer):

• A is correct: In a Router LSA, the "Link State ID" and "Advertising Router" fields both hold the originating router's Router ID - so 10.0.12.1 as Router ID is a valid, readable fact from the LSA.
• C is correct: The presence of transit-network link entries in the Router LSA implies the router has reached Full adjacency state with a DR, confirming adjacencies exist.
• D is correct: The Router LSA flags field includes an E-bit (External bit); when set, it marks the router as an ASBR (AS Boundary Router), which is exactly what "supports import of external routes" means.

Memory tip: Think of Router LSA flags as "BEV" - Border router (ABR), External routes (ASBR), Virtual link endpoint. There is no D for DR - DR lives in the Network LSA, not the Router LSA.

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