Free Huawei H12-891_V1.0 Practice Exam with Questions & Answers | Set: 7

NAFTIR (Network Address Flow Traffic Incoming Rate) policingis a traffic control mechanism that can only be applied toinboundtraffic.

Purpose:

Monitorsandlimitsthe traffic entering a network device.

Preventsupstream devices fromoverloadingthe network with excessive data.

Key Fact:Outbound policing requires different mechanisms likeQoS shapingortraffic scheduling.

✅Reference:Huawei HCIE-Datacom Study Guide - Traffic Policing and Shaping

Understanding SR-MPLS TE (Segment Routing MPLS Traffic Engineering)

????What is SR-MPLS TE?

Segment Routing (SR) replaces traditional MPLS LDP/RSVP-TE signaling.

UsesSR-TE policiesto define network pathswithout requiring per-flow state on intermediate routers.

????How is the SR-MPLS TE Path Calculated?

✅By the SDN Controller (Centralized Path Computation)

The controller (e.g.,Huawei iMaster NCE) calculates theoptimal SR pathbased on:

Bandwidth requirements

Latency constraints

Traffic policies

The controllerthen delivers the SR policy to the ingress router.

✅By the Ingress Router (Distributed Path Computation)

Theingress routercomputes theSR path dynamicallybased onlocal constraints.

This method is usefulwhen no centralized controller is available.

Why is the Answer TRUE?

✅Both centralized (controller-based) and distributed (ingress router-based) path computation are supported in SR-MPLS TE.

Real-World Application:

5G and Cloud WANs:Centralized path optimizationreduces congestion dynamically.

Enterprise Networks:Local path computation ensuresfast rerouting in case of failures.

✅Reference:Huawei HCIE-Datacom Guide – SR-MPLS TE and Path Computation Methods

Understanding MPLS Label Retention Modes

In MPLS (Multiprotocol Label Switching), aLabel Switching Router (LSR)can operate in one of two label retention modes:

1️⃣Liberal Label Retention Mode (LLRM)

Stores all labels receivedfrom neighbors, even if they are not immediately used.

Advantage:Fast convergenceduring link failures.

Disadvantage:Consumes more memory & label space.

2️⃣Conservative Label Retention Mode (CLRM)

Only keeps labels for the best next-hop path.

Advantage:Saves memory & label space.

Disadvantage:Slower convergence when topology changes.

Why are C and D Correct?

✅C. An LSR reserves all labels distributed by its neighbor.

Correct:InLiberal Mode, the routeraccepts and stores all labelsreceived, even for non-best paths.

✅D. The liberal mode requires more memory and label space.

Correct:Since the routerkeeps all labels, it requireshigher memory & storage.

Why are A and B Incorrect?

❌A. An LSR retains labels from a neighboring LSR only when the neighbor is its next hop.

Incorrect:This describesConservative Mode, not Liberal Mode.

❌B. This label retention mode saves memory and label space.

Incorrect:Liberal Mode consumes more memory, not less.

Real-World Application

Liberal Mode is used in large-scale MPLS networks where fast failover is critical.

Conservative Mode is preferred in memory-constrained environments.

✅Reference:Huawei HCIE-Datacom Study Guide – MPLS Label Retention Modes

Comprehensive and Detailed Explanation:

✔Fit APs require additional configurations before going online, such as:

AP authentication and onboardingthroughDHCP Option 148ormanual registration.

Firmware upgrade and provisioningfrom iMaster NCE-Campus.

Policy enforcementand VLAN assignment.

Since additional steps are required,Fit APs do not go online immediately, making the statementFALSE.

????Reference:Huawei HCIE Datacom – AP Registration and Authentication

✔TI-LFA (Topology Independent Loop-Free Alternate)is an enhancedFast Reroute (FRR) mechanismused inSR-MPLSnetworks.

✔How TI-LFA Works:

A virtual node is created, aggregating multiple route advertisements.

Backup paths are precomputedusingSegment Routing (SR) SIDs.

When a link failure occurs, traffic isrerouted in <50mswithout waiting forIGP convergence.

????Reference:Huawei HCIE Datacom – TI-LFA and SR-MPLS TE Protection

Virtual Networks in Huawei CloudCampus Solution:

Virtual networks (VNs) aresegmented based on services(e.g., IoT, Guest Wi-Fi, Enterprise Wi-Fi).

Each VN has its ownrouting and forwarding instance(VRF).

Isolation Between Virtual Networks:

By default,different virtual networks are isolated.

If inter-VN communication is required, it must be manually configuredusingpolicy-based routing (PBR), inter-VRF routing, or firewall policies.

Reference from Huawei HCIE-Datacom Documentation:

Huawei CloudCampus Solution Guide – Virtual Networks and Segmentation

HCIE-Datacom Training Material – Policy-Based Inter-VN Communication

Huawei’sNetwork Access Control (NAC)Portal authentication supports various identity authentication methods for user login via a web page. These include:

Username and password— standard method.

Passcode— one-time password or PIN.

SMS verification code— users receive a dynamic code via SMS for identity verification.

However:

MAC addressauthentication is used inMAC-based authentication, not Portal. MAC authentication allows a device to be authenticated using its MAC address without user interaction (i.e., not via a Portal page).

Correct answer: D. User’s MAC address

HTTP/2 is a TCP-based protocol, not UDP-based. It runs on top of TCP port 443 (usually via TLS). The protocol enhances performance using multiplexing, header compression, and stream prioritization, but it still relies on TCP, unlike newer protocols like HTTP/3, which uses UDP and QUIC.

Exact Extract - Huawei Application Networking Fundamentals:

“HTTP/2 continues to use TCP as its transport layer, introducing improvements like multiplexing over a single TCP connection. UDP-based HTTP/3 is a separate protocol built on QUIC.”

In Huawei’sCloudCampus Solution, VNs (Virtual Networks) areisolated by defaultfor security purposes. To enableinter-VN communication, you must explicitly configure policies that allow traffic between different VNs.

The correct way to control and enable this communication is viarouting policies, especiallyinter-VN routing policieson thecore or border nodes.

Static routesorOSPF deploymentsare not sufficient or appropriate for policy-controlled VN communication in this context.

Correct answer: D. Deploy a routing policy

NETCONF architecture consists of the following conceptual layers:

Secure Transport Layer – Ensures confidentiality (e.g., SSH, TLS)

Messages Layer – Handles framing and encoding (XML-based)

Operations Layer – Includes , , , etc.

Content Layer – Carries the actual configuration and state data defined by YANG models

This makes Option D correct.

Exact Extract – Huawei HCIE-Datacom NETCONF Architecture Overview:

“NETCONF is divided into four conceptual layers: secure transport, message framing, operations, and content layers.”