nerdexam
Cisco

352-001 · Question #547

Which OSPF design consideration, with regards to simplicity and address preservation, must be considered when connecting two Layer 3 switches directly using 10 GBASE-T cabling and formatting an OSPF n

The correct answer is E. The OSPF network type must be set to point-to-point. When two Layer 3 switches are connected directly via a point-to-point link, setting the OSPF network type to point-to-point eliminates unnecessary DR/BDR election and allows /31 subnets to conserve IP addresses.

Layer 3 Control Plane

Question

Which OSPF design consideration, with regards to simplicity and address preservation, must be considered when connecting two Layer 3 switches directly using 10 GBASE-T cabling and formatting an OSPF neighbor adjacency?

Options

  • AMesh groups must be included in the design
  • BThe OSPF Hello and Dead timers must be tuned to detect failures as quickly as possible
  • CThe OSPF network type must be set to point-to-multipoint
  • DAn OSPF neighbor adjacency formed over loopback interfaces must be placed in Area 0
  • EThe OSPF network type must be set to point-to-point

How the community answered

(27 responses)
  • A
    4% (1)
  • B
    4% (1)
  • C
    7% (2)
  • E
    85% (23)

Why each option

When two Layer 3 switches are connected directly via a point-to-point link, setting the OSPF network type to point-to-point eliminates unnecessary DR/BDR election and allows /31 subnets to conserve IP addresses.

AMesh groups must be included in the design

Mesh groups are an OSPF feature for NBMA networks used to control flooding and are not applicable to a direct two-switch physical connection.

BThe OSPF Hello and Dead timers must be tuned to detect failures as quickly as possible

Tuning Hello and Dead timers addresses failure detection speed, not the simplicity or address-conservation concerns stated in the question.

CThe OSPF network type must be set to point-to-multipoint

Point-to-multipoint network type is designed for hub-and-spoke topologies where one interface reaches multiple remote peers, not for a direct physical link between two switches.

DAn OSPF neighbor adjacency formed over loopback interfaces must be placed in Area 0

Placing loopback-based adjacencies in Area 0 is a backbone adjacency design pattern unrelated to the design considerations for a direct 10GBASE-T physical link.

EThe OSPF network type must be set to point-to-pointCorrect

Ethernet interfaces default to the OSPF broadcast network type, which triggers a DR/BDR election even on a two-device segment where it provides no benefit, adding unnecessary complexity. Setting the OSPF network type to point-to-point removes the DR/BDR requirement and supports /31 prefix addressing per RFC 3021, satisfying both the simplicity and address preservation design goals simultaneously.

Concept tested: OSPF point-to-point network type on direct Layer 3 links

Source: https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13683-20.html

Topics

#OSPF network type#point-to-point#address conservation#adjacency

Community Discussion

No community discussion yet for this question.

Full 352-001 Practice