Free Practice Questions for Huawei H12-821_V1.0 Exam

In dual-link MSB networking with load balancing, the new AP will connect to the AC with the lower number of connected APs. In this case, AC2 has only 20 connected APs, while AC1 has 100. Therefore, the new AP will connect to AC2 ​.

The Local-Preference attribute is used within an AS to influence outbound traffic paths. The default value is 100, and it is a well-known discretionary attribute, meaning it is not mandatory and does not travel across AS boundaries ​.

On Huawei devices, multiple BGP processes can be configured on the same router, but they are typically used for specific use cases such as multi-instance deployments or virtual routers. This flexibility is supported by Huawei's routing protocols ​.

Comprehensive and Detailed in-depth Step-by-Step Explanation:

BGP confederations are used to reduce the complexity of IBGP full-mesh connections within a large AS by dividing the AS into multiple sub-ASs (called "member ASs") while still appearing as a single AS to external ASs. Below is an analysis of each option:

A. The ASs outside a confederation still consider the confederation as one AS:

This is true. Externally, the entire confederation is seen as a single AS, identified by the main AS number.

B. After a confederation is configured, the original IBGP attributes can be retained:

This is true. The configuration of a confederation does not affect the IBGP attributes exchanged between routers.

C. After a confederation is configured, the original AS number is used as the confederation ID of each router:

This is true. The main AS number is used as the Confederation Identifier for all member ASs in the confederation.

D. A confederation divides an AS into several sub-ASs, and EBGP full-mesh connections are established in each sub-AS:

This is false. Within each sub-AS of a confederation, IBGP connections are still used (not EBGP). Confederations are designed to reduce the number of IBGP full-mesh connections required within a large AS by creating smaller, manageable sub-ASs.

Therefore, the correct answer is D.

 DIS and DR Election

The IS-IS Designated Intermediate System (DIS) is responsible for generating and updating pseudonode LSPs on a broadcast network.

Unlike OSPF DR, the IS-IS DIS does not preempt by default. This behavior avoids unnecessary flapping in the network due to frequent DIS re-elections.

 HCIP-Datacom-Core Reference

The characteristics of DIS and DR behavior are explained in IS-IS network operation chapters​​.

A is false – The correct formula is: Skew_Time = (256 - Priority)/256 × Advertisement_Interval.

B is false – By default, the preemption delay is typically 0s, not 1s, meaning a higher-priority backup router can preempt immediately unless configured otherwise.

C is true – The default Advertisement interval in VRRP is 2 seconds.

D is true – The formula Master_Down_Interval = 3 × Advertisement_Interval + Skew_Time is correct.

Reference from Huawei HCIP-Datacom-Core Technology Study Guide:

“The VRRP Skew_Time is calculated as (256 - Priority)/256 × Adver_Interval. The Master_Down interval includes this Skew_Time to stagger failover.”

(Chapter: High Availability – Section: VRRP Timer Mechanism)

 OSPF Authentication Overview

The Auth Type field in the OSPF packet header determines the authentication mode. If the Auth Type is 1, plaintext authentication is used.

Plaintext authentication involves transmitting the password in an easily readable format, which is less secure compared to MD5.

 HCIP-Datacom-Core Reference

Authentication mechanisms, including plaintext authentication, are detailed in the OSPF security configuration chapter, confirming that Auth Type = 1 corresponds to plaintext​​.