352-001 Question #21: Real Exam Question with Answer & Explanation

The correct answer is A: a connection to 10.1.5.0/24 and links to R3, R2, and R1. The Designated Router generates a Type 2 Network LSA for its multi-access segment that lists the network and all fully adjacent routers attached to that segment, including the DR itself.

Question

Refer to the exhibit. All routers in this network are configured to place all interfaces in OSPF area 5. R3 is the designated router on the 10.1.5.0/24 network. If you examine the OSPF database on R4, what would the network (type 2) LSA, generated by R3, contain?

Exhibit

Options

Aa connection to 10.1.5.0/24 and links to R3, R2, and R1
Ba connection to 10.1.5.0/24 and links to R2 and R1
Cconnections to 10.1.5.0/24 and 10.1.1.0/31
Dno connections, R3 does not generate a network (type 2) LSA in this network

Explanation

The Designated Router generates a Type 2 Network LSA for its multi-access segment that lists the network and all fully adjacent routers attached to that segment, including the DR itself.

Common mistakes.

B. This option omits R3 itself; the DR is always included as an attached router in the Type 2 LSA it originates, since the DR is also connected to the segment it is describing.
C. A Type 2 LSA covers exactly one multi-access transit segment; subnets such as 10.1.1.0/31 are point-to-point links described in separate Router (Type 1) LSAs and are never bundled into a Network LSA.
D. R3 is the elected DR on 10.1.5.0/24, and OSPF mandates that the DR generate a Network LSA for every multi-access segment on which it holds that role.

Concept tested. OSPF Type 2 Network LSA generated by the DR

Reference. https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/7039-1.html

Community Discussion

No community discussion yet for this question.

Full 352-001 Practice