nerdexam
Cisco

350-401 · Question #759

Which two statements about the OSPF two-way neighbor state are true? (Choose two.)

The correct answer is A. Each neighbor receives its own router ID in a hello packet from the other neighbor. E. Each neighbor receives an acknowledgement of its own hello packet from the other neighbor.. In the OSPF Two-Way neighbor state, each router has received a Hello packet from its neighbor that explicitly lists its own Router ID in the Neighbor field, confirming bidirectional communication.

Submitted by carlos_mx· Mar 6, 2026Implement OSPF

Question

Which two statements about the OSPF two-way neighbor state are true? (Choose two.)

Options

  • AEach neighbor receives its own router ID in a hello packet from the other neighbor.
  • BEach neighbor receives a hello message from the other neighbor.
  • CIt is valid only on NBMA networks.
  • DIt is valid only on point-to-point networks.
  • EEach neighbor receives an acknowledgement of its own hello packet from the other neighbor.
  • FEach neighbor receives the router ID of the other neighbor in a hello packet from the other

How the community answered

(22 responses)
  • A
    86% (19)
  • B
    9% (2)
  • F
    5% (1)

Why each option

In the OSPF Two-Way neighbor state, each router has received a Hello packet from its neighbor that explicitly lists its own Router ID in the Neighbor field, confirming bidirectional communication.

AEach neighbor receives its own router ID in a hello packet from the other neighbor.Correct

The OSPF Two-Way (2WAY) state is reached when a router receives a Hello packet from a neighbor, and that Hello packet includes the router's own Router ID in its 'Neighbor' field, signifying bidirectional communication.

BEach neighbor receives a hello message from the other neighbor.

While each neighbor receives a Hello message, merely receiving a Hello only indicates one-way communication and corresponds to the 'Init' state, not the 'Two-Way' state.

CIt is valid only on NBMA networks.

The Two-Way state is a fundamental OSPF neighbor state that occurs on all network types, not exclusively on NBMA networks.

DIt is valid only on point-to-point networks.

The Two-Way state is a fundamental OSPF neighbor state that occurs on all network types, not exclusively on point-to-point networks.

EEach neighbor receives an acknowledgement of its own hello packet from the other neighbor.Correct

When a router receives its own Router ID within the 'Neighbor' field of an incoming Hello packet, it serves as an implicit acknowledgement that its own Hello packet was received by the sender, establishing two-way communication.

FEach neighbor receives the router ID of the other neighbor in a hello packet from the other

While routers exchange their own Router IDs in Hello packets, the specific condition for the Two-Way state is the receipt of *its own* Router ID in the *other's* Hello packet, not just the other's Router ID.

Concept tested: OSPF neighbor states (Two-Way)

Source: https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13689-18.html

Topics

#OSPF neighbor states#OSPF Hello protocol#Routing protocols

Community Discussion

No community discussion yet for this question.

Sign up to join the discussion
Full 350-401 Practice