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300-420 · Question #183

Refer to the exhibit. An architect must design a solution that uses the direct link between R1 and R2 for traffic from 10.10.10.0/24 toward network 10.10.20.0/24. Which solution should the architect…

The correct answer is D. Configure the link to provide multiarea adjacency. OSPF multiarea adjacency (defined in RFC 5185) allows a single physical link to participate in multiple OSPF areas simultaneously. In this scenario, the direct link between R1 and R2 is in a non-backbone area. OSPF always prefers intra-area routes over inter-area routes, and…

Advanced Addressing and Routing Solutions

Question

Refer to the exhibit. An architect must design a solution that uses the direct link between R1 and R2 for traffic from 10.10.10.0/24 toward network 10.10.20.0/24. Which solution should the architect include in the design?

Exhibit

300-420 question #183 exhibit

Options

  • AConfigure the OSPF cost of the link to a value lower than 30.
  • BLower the Administrative Distance for OSPF area 0.
  • CPlace the link into area 2 and install a new link between R1 and R2 in area 0.
  • DConfigure the link to provide multiarea adjacency.

How the community answered

(39 responses)
  • A
    3% (1)
  • B
    8% (3)
  • C
    18% (7)
  • D
    72% (28)

Explanation

OSPF multiarea adjacency (defined in RFC 5185) allows a single physical link to participate in multiple OSPF areas simultaneously. In this scenario, the direct link between R1 and R2 is in a non-backbone area. OSPF always prefers intra-area routes over inter-area routes, and inter-area routes require traversal through Area 0. By configuring multiarea adjacency on the direct link with Area 0, the link becomes treated as a backbone link in addition to its existing area, making the direct path an intra-area Area 0 path. This causes OSPF to prefer it for routing between the two networks. Lowering OSPF cost (A) may not overcome the area preference rules. Changing the Administrative Distance (B) affects protocol preference, not path selection within OSPF. Moving the link to Area 2 with a new Area 0 link (C) adds complexity unnecessarily.

Topics

#OSPF Multiarea#OSPF Virtual Links#Routing Path Selection#Network Design

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