Huawei H12-821 Exam Questions
HCIP-Datacom-Core Technology V1.0 (Page 19 )

Updated On: 12-Jun-2026

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See the following figure. All routers on the network run IS-IS and are in area 49.0001. By referring to the LSDB of R1, the Level-2 DIS is____. (Enter the device name, for example, R1.)



  1. R3

Answer(s): A

Explanation:

Based on the provided LSDB (Link State Database) of R1, the Level-2 DIS (Designated Intermediate System) can be determined by identifying the router with the highest priority or the highest system ID if the priorities are the same.

From the Level-2 Link State Database (LSDB) section:
The LSPID with the system ID 0100.0000.3003 (R3) is present.

Typically, the router with the highest system ID is elected as the DIS for Level-2 in the absence of priority differentiation.

Thus, the Level-2 DIS is R3.



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R1, R2, R3, and R4 run IS-IS, and the DIS priorities of their interfaces are shown in the following figure. If all these devices are started simultaneously, ______ will be elected as the DIS. (Enter the device name, for example, R1)

  1. R4

Answer(s): A

Explanation:

Based on the IS-IS election process for a Designated Intermediate System (DIS):
1. The router with the highest DIS priority is elected as the DIS.
2. If priorities are the same, the router with the highest MAC address (or system ID) is chosen.

From the provided diagram:
R4 has the highest DIS priority of 40.

Therefore, R4 will be elected as the DIS.



See the network shown in the following figure. R1 and R2 run IS-IS, and establish an adjacency. IS-IS is enabled on Loopback0 of R2 but disabled on Loopback3 of R2. The configurations shown in the figure are performed in the IS-IS process of R2.
Which of the following statements are true? (Choose all that apply.)

  1. The routing table of R1 contains the route 10.0.2.3/32.
  2. The routing table of R1 does not contain the route 10.0.2.3/32.
  3. The routing table of R1 does not contain the routes 10.0.2.2/32 and 10.0.2.3/32.
  4. The routing table of R1 contains the route 10.0.2.2/32.

Answer(s): B,D

Explanation:

Configuration Details:
set-overload:

- The overload bit in IS-IS indicates that the router should not be used for transit traffic. However, this does not prevent the router from advertising its own directly connected routes (like Loopback0).
import-route direct:

- This command imports directly connected routes into IS-IS. Thus, R2 advertises the connected route 10.0.2.2/32 (Loopback0).
Loopback Interfaces:
IS-IS is enabled only on Loopback0 (10.0.2.2/32), so R2 advertises this route.

IS-IS is disabled on Loopback3 (10.0.2.3/32), so this route is not advertised.

Impact on R1's Routing Table:
10.0.2.2/32: R2 advertises this route to R1, and it is added to R1's routing table.

10.0.2.3/32: This route is not advertised because IS-IS is disabled on Loopback3, so it does not appear in

R1's routing table.



Which of the following statements regarding the BGP error display of a router is false?

  1. The error occurred at 11:40:39 on March 22, 2010.
  2. The neighbor address of this router is 10.1.1.2.
  3. The error may be caused by the incorrect peer AS number.
  4. Error Type indicates that the BGP error is caused by the neighbor relationship error.

Answer(s): C

Explanation:

Analysis of the Error Display:
1. Error Type: Peer Error
This indicates a problem with the BGP neighbor relationship, not an AS number mismatch.

2. Error Info: Router-ID conflict
The specific error is a Router-ID conflict, meaning two BGP neighbors are configured with the same

Router ID. This is unrelated to the peer AS number.
3. Date/Time: 2010-03-22 11:40:39
The error occurred at the specified time.

4. Peer Address: 10.1.1.2
This is the address of the BGP peer causing the issue.

The error may be caused by the incorrect peer AS number.
False: The error is due to a Router-ID conflict, not an incorrect AS number.



Which of the following statements regarding the display bgp routing-table command output is true?

  1. The route to the destination address 192.168.1.0 is learned through AS 200.
  2. The MED value of the route to the destination address 192.168.1.0 is 100.
  3. The route to the destination address 192.168.1.0 is not the optimal route in the BGP routing table.
  4. The route to the destination address 192.168.1.0 is injected into the BGP routing table using the network command.

Answer(s): D

Explanation:

Analysis of the Output:
5. Route: 192.168.1.0/24
This is the destination address in the BGP routing table.

6. NextHop: 10.1.1.1
The next-hop IP address for this route is 10.1.1.1.

7. MED: 0
The Multi-Exit Discriminator (MED) value is 0, indicating no specific MED preference has been assigned.

8. Origin: i
The i (IGP) origin code indicates that the route was injected into BGP using the network command, as opposed to being learned through redistribution or external sources.
9. Status Code: *>
The *> indicates that the route is valid (*) and is the best route (>).

The route to the destination address 192.168.1.0 is injected into the BGP routing table using the network command.
True: The i origin code confirms that the route was injected using the network command.



Multiple BGP processes cannot be configured on the same router.

  1. TRUE
  2. FALSE

Answer(s): B

Explanation:

Multiple BGP (Border Gateway Protocol) processes can be configured on the same router. This is referred to as BGP multi-instance or multiple BGP processes, which allows different BGP routing domains to run independently on the same router. Each BGP process can have its own set of configurations, neighbor relationships, and routing tables.
Key Points:
Multiple BGP processes can be used to segment BGP routing domains, typically in environments where different routing policies or separate AS numbers are needed.
These processes are independent of each other, meaning they do not exchange information unless explicitly configured (e.g., through redistribution).
The ability to run multiple BGP processes provides flexibility in network design, especially for complex topologies.
Thus, the statement that multiple BGP processes cannot be configured on the same router is false.



Which of the following parameters are not mandatory during the configuration of a BGP peer? (Choose all that apply.)

  1. password
  2. Peer IP address
  3. as-number
  4. description

Answer(s): A,D

Explanation:

While password (used for authentication in BGP sessions) is a good security practice, it is not mandatory to configure a password for a BGP peer. If no password is configured, BGP will still function but without authentication.
The description field is used for human-readable purposes and does not affect the functionality of BGP. It can be added for documentation or clarity, but it is not required for BGP operation.



Which of the following statements regarding the MED value in BGP are true? (Choose all that apply.)

  1. According to BGP route selection rules, the MED value has a lower priority than AS Path, Preferred-Value,
    Local-Preference, and Origin.
  2. The default MED value of BGP routes is 0.
  3. By default, BGP can compare the MED values of routes from different ASs.
  4. By default, if there is no MED value in routes, the value 0 is used. If the bestroute med-none-as-maximum command is configured, the maximum MED value 4294967295 is used.

Answer(s): A,B,D

Explanation:

According to BGP route selection rules, the MED value has a lower priority than AS Path, Preferred- Value, Local-Preference, and Origin.
The MED (Multi-Exit Discriminator) is used to indicate the preferred exit point for traffic entering the AS, but in the BGP route selection process, the MED is compared after considering AS Path, Preferred-Value, Local- Preference, and Origin. This means MED has a lower priority than these factors when BGP is determining the best path.
The default MED value of BGP routes is 0.
The default MED value is indeed 0 for BGP routes. If no MED value is configured, BGP assumes a value of 0 when comparing routes.
By default, if there is no MED value in routes, the value 0 is used. If the bestroute med-none-as- maximum command is configured, the maximum MED value 4294967295 is used.
By default, if a route does not have a MED value, BGP assumes the value 0. If the bestroute med-none- as-maximum command is configured, routes without a MED value are treated as having the maximum possible MED value of 4294967295, which is a configurable option in some BGP implementations.



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