Huawei Updated H12-821_V1.0 Exam Questions and Answers by roisin

Comprehensive and Detailed In-Depth Explanation:

Stub areas do not allow external routes (Type 5 LSAs).

Since ASBRs are responsible for redistributing external routes into OSPF, they cannot exist in a stub area .

If an ASBR were placed in a stub area, it would attempt to inject external routes into the OSPF domain, which contradicts the stub area rules.

To allow external routes, Not-So-Stubby Areas (NSSAs) are used instead, which allow ASBRs and use Type 7 LSAs to carry external routes.

???? Reference: Huawei HCIA-Datacom Study Guide, OSPF Area Types and ASBR Restrictions.

A is correct – Confederations are specifically designed for large-scale BGP deployments where a full IBGP mesh is impractical.

B is correct – Sub-ASs within a confederation establish EBGP-like connections between each other but behave like IBGP within the overall AS. These sub-ASs do not require full-mesh inside the confederation , but EBGP rules are followed between sub-ASs.

C is false – Not all devices need to be reconfigured . Devices within the same sub-AS retain normal IBGP behavior and minimal changes.

D is correct – Confederation is transparent to external peers , so the logical topology remains the same from outside the AS.

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

“BGP confederation divides an AS into multiple sub-ASs. EBGP-like sessions are established between sub-ASs, while reducing IBGP mesh complexity. The external AS still sees the AS as one unit.”

(Chapter: BGP Scalability Enhancements – Section: Confederation)

 Non-Client Definition in IBGP

In an IBGP setup with a Route Reflector (RR), a non-client is an IBGP peer that is neither the RR itself nor its client.

Non-clients must establish fully meshed IBGP connections with all other non-clients and the RR because IBGP rules prohibit route propagation between non-clients without a direct connection.

 HCIP-Datacom-Core Reference

The behavior of non-clients in an RR topology is clearly outlined in the BGP implementation chapters​​.

VRRP defines the following states:

Initialize – The router is starting up or has not joined a VRRP group.

Backup – The router is in standby and monitors the Master.

Master – The only state where the device forwards traffic for the virtual IP address .

Only the router in the Master state owns the virtual MAC and responds to ARP for the virtual IP.

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

“In VRRP, only the Master forwards packets destined for the virtual IP address. Backup routers take over only if the Master fails.”

(Chapter: VRRP Concepts – Section: State Roles and Transitions)