Huawei H12-821 Exam Questions
HCIP-Datacom-Core Technology V1.0 (Page 9 )

Updated On: 12-Jun-2026

When the MTUs of two interfaces connecting two routers in a broadcast network do not match, which of the following statements of two routers regarding OSPF neighbor state change is true?

  1. The OSPF neighbor state remains Init.
  2. The OSPF neighbor state remains Exstart.
  3. The OSPF neighbor state can be Full.
  4. The OSPF neighbor state remains 2-way.

Answer(s): B

Explanation:

When the MTUs of two interfaces on a broadcast network do not match, the OSPF neighbor adjacency cannot fully form due to a mismatch during the Database Exchange (DBD) process. The Exstart state is where OSPF determines the master and slave roles for exchanging Database Description (DBD) packets. If the MTUs of the interfaces differ, the routers cannot agree on the exchange, and the process is stalled.



Which of the following methods is usually used by a network administrator to configure a newly purchased device for the first time?

  1. Telnet
  2. SNMP
  3. Login through the Console port
  4. FTP

Answer(s): C

Explanation:

When a newly purchased device is being configured for the first time, it typically does not have any pre- configured IP addresses or remote access protocols enabled. Therefore, the Console port is the most reliable and commonly used method to configure the device for the first time.



A forwarding information database (FIB) can directly guide packet forwarding on a router.

  1. TRUE
  2. FALSE

Answer(s): A

Explanation:

A Forwarding Information Base (FIB) is a data structure used by a router to make forwarding decisions. It is derived from the router's routing table (RIB - Routing Information Base) and contains the next-hop information for forwarding packets efficiently.

Key Characteristics of the FIB:
5. Purpose:
The FIB is used to directly guide the forwarding of packets.

It contains precomputed information for efficient packet forwarding, such as destination prefixes, next hops,

and outgoing interfaces.
6. Separation from the RIB:
While the RIB contains all the routing information (from OSPF, BGP, RIP, etc.), the FIB includes only the best routes needed for actual packet forwarding.
This separation enhances performance by avoiding complex route calculations during packet forwarding.

7. Hardware Usage:
In modern routers, the FIB is often implemented in hardware (e.g., TCAM on high-speed switches) to ensure fast packet forwarding.



Which of the following statements regarding OSPF route summarization commands are true? (Choose all that apply.)

  1. The asbr-summary command is executed in the OSPF view.
  2. The abr-summary command is executed in the OSPF area view.
  3. advertise is the default parameter of the abr-summary command. That is, if not-advertise is not specified in the abr-summary command, the advertise parameter takes effect by default,
  4. not-advertise is the default parameter of the abr-summary command. That is, if advertise is not specified in the abr-summary command, the not-advertise parameter takes effect by default.

Answer(s): B,C

Explanation:

The abr-summary command is executed in the OSPF area view.
True: The abr-summary command is used to summarize routes advertised between areas. It is executed in the OSPF area view because route summarization between areas occurs at the ABR (Area Border Router) level.
advertise is the default parameter of the abr-summary command. That is, if not-advertise is not specified in the abr-summary command, the advertise parameter takes effect by default.
True: By default, the abr-summary command advertises the summarized route. If not-advertise is not explicitly specified, the advertise behavior takes effect.



DRAG DROP (Drag and Drop is not supported)

BFD for OSPF is deployed on a directly connected link. If the physical link is disconnected, drag the following BFD processes to the corresponding sequence numbers.

Select and Place:

  1. See Explanation section for answer.

Answer(s): A

Explanation:




1. Link fault alarm: The physical disconnection of the link triggers a fault alarm on the interface.
2. The BFD session goes down: As BFD relies on the direct connectivity of the link, the session goes down due to the link fault.
3. Interrupted OSPF neighbor relationship: With the BFD session down, OSPF detects the neighbor failure and terminates the neighbor relationship, initiating route recalculation.



See the command output of a router below.
Which of the following statements is true?

  1. The router ID is 10.0.12.2.
  2. The interface cost is 1500.
  3. This router is a BDR.
  4. The interface IP address is 10.1.12.1.

Answer(s): C

Explanation:

This router is a BDR.
True: The output states "State: BDR", indicating that this router is the Backup Designated Router (BDR) for the OSPF process.



See the command output of a router below.
Which of the following statements are true? (Choose all that apply.)

  1. The interface IP address is 10.1.12.1.
  2. The network type of the interface is broadcast.
  3. The router is a DR.
  4. The router ID is 10.1.1.1.

Answer(s): B,C,D

Explanation:

The network type of the interface is broadcast.
True: The output explicitly states "Type: Broadcast", confirming that the network type is broadcast.
The router is a DR.
True: The output explicitly states "State: DR", indicating that this router is the Designated Router (DR).
The router ID is 10.1.1.1.
True: The output explicitly states "Router ID 10.1.1.1", confirming that this is the router's ID.



Which of the following LSAs are advertised only within a single area?

  1. Network LSA
  2. Router LSA
  3. Summary LSA
  4. AS External LSA

Answer(s): A,B

Explanation:

Network LSA (Type 2):
Network LSAs are generated by the Designated Router (DR) on a broadcast or NBMA network.

They describe all the routers connected to the segment and are advertised only within the local area.

Router LSA (Type 1):
Router LSAs are generated by every router to describe its directly connected interfaces, link types, and costs.
They are advertised only within the local area.



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