Pass the Huawei HCIE-Datacom H12-891_V1.0 Questions and answers with CertsForce

Comprehensive and Detailed In-Depth Explanation:

In OSPF, a Not-So-Stubby Area (NSSA) is a type of area that allows for the injection of external routes (like a standard area) while maintaining some stub area characteristics.

Type 7 LSAs (NSSA External LSAs) are generated by ASBRs within an NSSA.

An ABR at the NSSA boundary translates these Type 7 LSAs into Type 5 LSAs to propagate them into the rest of the OSPF domain.

This translation is necessary because Type 5 LSAs are the standard method for advertising external routes in OSPF.

Therefore, the statement is TRUE.

In OSPF (Open Shortest Path First), routers connected over broadcast networks (like Ethernet) elect a Designated Router (DR) and Backup Designated Router (BDR). DR election is based on the interface priority. If the priority is set to 0, the router cannot become a DR or BDR.

When both routers have a priority of 0, no DR or BDR will be elected, and since the election fails, the neighbor relationship between the two routers will not advance beyond the 2-Way state. In this state, the routers acknowledge each other but do not exchange routing information in detail (as they only form full adjacency with the DR/BDR).

Therefore, the OSPF neighbor relationship remains in the 2-Way state.

In Huawei’s Free Mobility solution:

Authentication Point (AP): Identifies users and associates them with a Security Group Tag (SGT) upon access.

Policy Enforcement Point (PEP): Enforces policies between different security groups, such as allowing or denying traffic.

Key points:

A is correct — The PEP enforces inter-group access based on defined policies.

B is incorrect — AP and PEP can be on separate devices, offering deployment flexibility.

C is incorrect — The policy enforcement happens at the PEP, not the AP. AP ' s job is to authenticate and tag traffic.

D is correct — AP and PEP can be deployed on different devices.

Correct answers: A, D

NETCONF defines datastores to manage device configurations:

running: Active configuration in use

candidate: Staging area for changes before applying

startup: Configuration loaded on reboot

NETCONF operations:

< commit > : Applies changes from candidate → running → ✅

< delete-config > : Deletes a specified datastore (e.g., startup) → ✅

< validate > : Validates syntax/logic in the candidate datastore → ✅

Statement D is incorrect: < commit > never submits config from startup to running — that’s handled automatically at boot time, not through NETCONF commands.

Correct answer: D

Error analysis:

The error SSLError and CertificateError indicates the server ' s SSL certificate ' s hostname doesn ' t match the IP address being used in the request.

This happens when a certificate is issued for a domain (like devzone.huawei.com), but the client accesses it via an IP address (139.9.213.72), causing a trust failure.

Correct statements:

A — ✅: The client doesn ' t trust the SSL certificate → correct.

B — ✅: SSL verification fails due to hostname mismatch.

C — ✅: Disabling verification with verify=False bypasses the check (only recommended in lab/testing environments).

D — ❌: Uses http instead of https, which changes protocol and defeats the purpose of SSL. Also uses POST without API path.

Correct answers: A, B, C

Congestion Avoidance in Networking

Congestion avoidance mechanisms prevent packet loss and delay by managing queues before congestion occurs.

Common Congestion Avoidance Techniques:

Weighted Random Early Detection (WRED) – Randomly drops low-priority packets before congestion builds up.

Explicit Congestion Notification (ECN) – Marks packets instead of dropping them to signal congestion.

Queue Management – Techniques like priority queuing (PQ) and weighted fair queuing (WFQ) help prevent congestion.

Reference from Huawei HCIE-Datacom Documentation:

Huawei QoS Configuration Guide – Congestion Avoidance Technologies

HCIE-Datacom Study Material – Traffic Management and Queue Optimization

Comprehensive and Detailed Explanation:

✔ SR-MPLS Policy candidate paths are used for flexible path selection and load balancing in Segment Routing (SR-MPLS) networks.

✔ Correct Statements:

✅ (A) Each candidate path can have multiple segment lists, each with its own weight for load balancing.

✅ (B) Load balancing is supported both between candidate paths and within segment lists.

✅ (C) An SR-MPLS Policy can contain multiple candidate paths, each with a preference value.

✅ (D) The candidate path with the highest preference is selected as the primary path.

???? Reference: Huawei HCIE Datacom – SR-MPLS Policy Path Selection

Node segments in SR-MPLS (Segment Routing over MPLS) are typically automatically generated and distributed via IGP protocols (such as IS-IS or OSPF) using SR extensions. There is no need to manually configure node segments on every router.

Exact Extract – Huawei HCIE-Datacom Study Guide – Segment Routing:

“Node SIDs are automatically generated and advertised by IGPs with SR extensions. Manual configuration is not required except in special cases like adjacency SIDs.”