Refer to the exhibit. Which two design options reduce the size of OSPF database? (Choose two)

The correct answer is A. Prefix suppression D. Layer 2 link aggregation between core switches. OSPF database (LSDB) size is driven by the number of LSAs, which correlates to the number of links and prefixes advertised. Prefix suppression (A) instructs routers to omit transit point-to-point link prefixes from their LSAs. Since routers only need to know about loopback/endpoi

Layer 3 Control Plane

Question

Exhibit

Options

APrefix suppression
BLoop Free Alternate
CIncremental SPF
DLayer 2 link aggregation between core switches
EType 3 LSA filtering

How the community answered

(13 responses)

A
77% (10)
B
8% (1)
C
8% (1)
E
8% (1)

Explanation

OSPF database (LSDB) size is driven by the number of LSAs, which correlates to the number of links and prefixes advertised. Prefix suppression (A) instructs routers to omit transit point-to-point link prefixes from their LSAs. Since routers only need to know about loopback/endpoint prefixes for reachability (not transit subnets), suppressing them reduces LSA count and LSDB size without affecting connectivity. Layer 2 link aggregation (D) replaces multiple individual Layer 3 links between core switches with a single logical Layer 2 port channel. OSPF only sees one adjacency and one link instead of several, directly reducing the number of LSAs. Loop Free Alternate (B) is a fast-reroute mechanism and does not affect LSDB size. Incremental SPF (C) optimizes SPF recalculation speed but does not shrink the database. Type 3 LSA filtering (E) applies only between OSPF areas at ABRs and would not reduce the database within a single-area design.

Topics

#OSPF optimization#prefix suppression#LSA filtering#link aggregation

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