Based on the provided OSPF configuration for R1 and R2, which statement accurately describes their adjacency and route calculation capabilities?

Question

Options

• AR1 and R2 can establish an adjacency relationship, but cannot complete route calculation.
• BR1 and R2 can establish an adjacency relationship and complete route calculation.
• CR1 and R2 cannot establish an adjacency relationship because the configuration of the interface is inconsistent.
• DR1 and R2 cannot establish an adjacency relationship because the OSPF process numbers are inconsistent.

• A
  78% (28)
• B
  14% (5)
• C
  6% (2)
• D
  3% (1)

Explanation

Option A is correct because OSPF process numbers are locally significant - R1 and R2 can form a full adjacency even when their process numbers differ, since only Hello parameters (area ID, timers, authentication, subnet) must match. However, if both routers share the same Router ID (a common trap in exam configs), the LSDB becomes corrupted: each router treats the other's LSAs as its own self-originated LSAs and may flush or ignore them, making SPF calculation impossible.

Why the distractors fail:

• B is wrong because adjacency succeeding doesn't guarantee a usable LSDB - duplicate Router IDs silently break route calculation after the neighbors reach Full state.
• C is wrong because the interface is consistent (matching area, timers, subnet) - that's precisely what allows adjacency to form.
• D is wrong because OSPF process numbers are locally significant and have no bearing on adjacency; routers with process 1 and process 100 can neighbor just fine.

Memory tip: Think "process number = your own business, Router ID = your public name." Two routers can shake hands regardless of their internal process numbering, but if they hand each other the same business card (duplicate RID), the network gets confused about who owns which routes.

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