Free Practice Questions for Huawei H12-891_V1.0 Exam

Comprehensive and Detailed In-Depth Explanation:

The correct configuration is qos car inbound cir 50000 pir 100000.

CIR (Committed Information Rate):The guaranteed minimum bandwidth, set to 50 Mbit/s (50000 kbps).

PIR (Peak Information Rate):The maximum allowable bandwidth, set to 100 Mbit/s (100000 kbps).

This configuration ensures that during peak hours, the minimum guaranteed bandwidth is 50 Mbit/s, while during off-peak hours, the bandwidth can increase to a maximum of 100 Mbit/s. The settings align with the carrier's requirements for dynamic bandwidth allocation based on network load.

GRE (Generic Routing Encapsulation) has the following benefits:

B. VPN Construction — GRE is often used to build site-to-site VPNs.

C. ARP Encapsulation — GRE supports Layer 2 protocol encapsulation such as ARP.

D. Multicast Support — GRE tunnels can encapsulate multicast packets, unlike traditional IPsec.

A. Enlarging the hop limit is incorrect — GRE does not inherently change TTL or hop behavior; routing protocols still use standard IP processing.

Exact Extract - Huawei HCIE-Datacom Tunneling Chapter:

“GRE can encapsulate multicast and broadcast packets and supports L2 protocols like ARP. It is often used for VPN construction over the internet.”

Comprehensive and Detailed In-Depth Explanation:1. Understanding SRv6 (Segment Routing over IPv6):SRv6 uses theIPv6 headeralong with an additionalSRH (Segment Routing Header)to implement segment routing within an IPv6 network. The SRH contains:Segment List (SL):A list of IPv6 addresses (segments) to traverse.SL (Segments Left):An integer that indicates thenumber of segmentsyet to be visited.Active Segment:Thenext IPv6 addressin the segment list, stored in theDestination Addressfield of the IPv6 header.2. Analyzing the Given Scenario:Thesegment list (SL)in the SRH header shows:FC04::400FC04::4FC03::3The segment list is processed inreverse order(from bottom to top).SL (Segments Left)indicates theindex of the active segmentin the list.TheDestination Addressin the IPv6 header is currentlyFC04::4, indicating that theactive segmentis thesecond elementin the list.3. Determining the Value of SL:Theindexingin the segment list starts from0.SinceFC04::4is thesecond segment (from the bottom), the value ofSLwill be1.This means that1 segment is leftto be processed after the current one (FC04::4).Once the packet reachesFC04::4, theSL value will decrement to 0, and the next segment (FC03::3) will be processed.4. Why the Answer is 1:TheSL value decreases as segments are processed.As the currentactive segmentis thesecond in the list (from the bottom), theSL value is 1.

Authentication Header (AH) in IPsec

TheAuthentication Header (AH) protocolis part ofIPsecand providesauthentication, integrity, and replay protectionbutdoes NOT provide encryption.

✅B. AH provides data origin authentication.

Ensures thatpackets come from a trusted sourceusing cryptographic signatures.

✅C. AH provides anti-replay protection.

Usessequence numbersto prevent attackers from replaying old packets.

✅D. AH provides data integrity authentication.

Ensuresdata integrityby verifying that packetshave not been tampered withduring transmission.

❌A. AH provides packet encryption – Incorrect!

AH does not encrypt packet contents.It only authenticates headers.

ESP (Encapsulating Security Payload) is used for encryption in IPsec.

Reference from Huawei HCIE-Datacom Documentation:

Huawei IPsec Configuration Guide – AH vs. ESP

HCIE-Datacom Training Material – IPsec Security Mechanisms

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Comprehensive and Detailed In-Depth Explanation:

ThegRPC-based telemetry protocolutilizesprotocol buffers (.proto files)to define the structure and data format used in communication between a client and a server. In Huawei's telemetry architecture, these files are categorized based on their roles in the data model.

1. RPC Layer:

File:huawei-grpc-dialin.proto

TheRPC layer (Remote Procedure Call layer)handles communication between the client and server.

The filehuawei-grpc-dialin.protodefines thegRPC service interfaces, message structures, and procedures for remote method invocation.

It is essential forestablishing communicationandinvoking telemetry data collection.

Function:Managesdial-in and dial-out connectionsbetween the telemetry client and the server.

2. Telemetry Layer:

File:huawei-telemetry.proto

Thetelemetry layeris responsible forcollecting, packaging, and exporting telemetry data.

The filehuawei-telemetry.protocontains thedata modelused for telemetry reporting, includingstreaming data formatsandtelemetry messages.

It defines how thecollected datais organized and transmitted.

Function:Provides astructured way to export telemetry datain real-time or batch mode.

3. Service Data Layer:

File:huawei-debug.proto

Theservice data layercontains data models related todiagnostics, debugging, and operational data.

The filehuawei-debug.protois used tocollect debugging informationfrom network devices.

This file is crucial fortroubleshooting and monitoring the healthof the system.

Function:Facilitatesdebugging and diagnostic telemetry data collection.

Why This Mapping Is Correct:

The mapping is based on thefunctional role of each layerand thepurpose of each .proto filein the Huawei gRPC-based telemetry architecture.

Correctly identifying the file location is crucial foreffective telemetry configurationanddata collection.

According to the displayed OSPF error statistics from the Huawei device, the key HELLO packet error shown is:

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CopyEdit

2 : Netmask mismatch

This indicates that the OSPF adjacency formation is failing due to a subnet mask mismatch between the two OSPF neighbors on the corresponding interface (GigabitEthernet 0/0/0). OSPF uses the subnet mask in Hello packets to ensure that neighbors are in the same network. If the masks do not match, OSPF will not form an adjacency.

From the Huawei Official HCIE-Datacom Study Guide (Version 3.0) — under the OSPF Troubleshooting Section:

"Netmask mismatch: If the subnet mask configured on the interfaces of OSPF neighbors does not match, a 'Netmask mismatch' error occurs. OSPF requires neighbors to be on the same subnet to establish an adjacency. This is a common reason for failure in adjacency formation."

(Reference: Huawei HCIE-Datacom V3.0, OSPF Troubleshooting Chapter, Section 4.2 – OSPF Hello and Adjacency Establishment Issues)

Thus, among the given options:

A. Area type inconsistency would result in an area ID mismatch error, not netmask.

B. Authentication mismatch would show a bad authentication key or type error.

D. Hello interval mismatches would trigger a Hello timer mismatch error.

Only C. The IP address masks of the interfaces are inconsistent directly matches the actual error observed: Netmask mismatch.

In Huawei’sVXLAN implementation, the typical mapping betweenVNIs (VXLAN Network Identifiers)andBDs (Bridge Domains)is:

1:1 mapping— each VNI is uniquely associated with a single bridge domain.

This allows properMAC learning and forwardingin the data plane for isolated tenant traffic.

Other mappings (N:1, 1:N, N:M) may be technically possible butnot recommendedor supported in most enterprise deployments.

Correct answer: B. 1:1

Understanding User Authentication Points in a Network

Authentication pointscan be deployed at different network layersbased on security and scalability needs:

✅Access Layer Authentication:

Ensureshigh security & granular control(user-level authentication).

Preferred inhigh-security enterprise networks.

✅Aggregation or Core Layer Authentication:

Reduces authentication overheadbutprovides less granular control.

Suitable forlarge-scale networkswhere authentication load needs to be balanced.

Analysis of the Answer Choices:

✅A. Deploying user authentication points at the access layer achieves granular permission management and high network security.

Correct:Providesfine-grained control per userand prevents unauthorized access.

✅B. Moving user authentication points from the access layer to the aggregation or core layer greatly reduces the number of user authentication points, thereby effectively mitigating the pressure on the AAA server.

Correct:Fewer authentication points meanless load on the AAA server.

✅C. Deploying user authentication points at the access layer has both advantages and disadvantages when compared to doing so at the aggregation or core layer. Policy association can be applied if user authentication points are deployed at the access layer.

Correct:Policy-based authentication isbest applied at the access layerforgranular control.

❌D. When user authentication points are moved from the access layer to the aggregation layer, MAC address authentication for users may fail.

Incorrect:MAC authentication worksat both layers, butpolicy adjustmentsmay be needed.

✅Reference:Huawei HCIE-Datacom Guide – User Authentication Strategies in Enterprise Networks

In BGP EVPN configuration forVXLAN-based networks, Huawei uses the command:

[bgp] advertise l2vpn evpn

This command enables the BGP process toadvertise routes from a VPN instance into the EVPN (L2VPN) address family, which is used for VXLAN control-plane operations like MAC/IP advertisement.

Option A (advertise irbvfi)— invalid command.

Option B (advertise vpnv4)— used for MPLS VPNs, not EVPN.

Option C (advertise irb)— not a recognized Huawei command.

Option Dis the correct and officially used command.

Correct answer: D. advertise l2vpn evpn

Understanding User Isolation in the Same VLAN

In a traditional VLAN,all devices within the same VLAN can communicateunless additional security policies are applied.To isolate users within the same VLAN, the following technologies can be used:

✅B. Port Isolation (Private VLAN or Layer 2 Isolation)

Prevents communication between ports within the same VLAN.

Common in enterprise and campus networksto improve security.

Example:Isolating guest users from employees within the same VLAN.

✅C. IPSG (IP Source Guard)

BlocksIP address spoofingwithin the same VLAN.

UsesDHCP snooping binding tableto verify whether a device is using anauthorized IP address.

✅D. Ethernet Port Security

Limits the number of MAC addressesallowed per port.

Preventsunauthorized devicesfrom communicating within the VLAN.

❌A. Super VLAN (Incorrect Choice)

Super VLANgroups multiple VLANs under a single Layer 3 gateway, but it doesnot provide isolationwithin the same VLAN.

Real-World Application:

Public Wi-Fi Networks:Ensures thatusers within the same VLAN cannot communicatewith each other.

Enterprise Security:Prevents unauthorized access or attacks withinshared VLANs.

✅Reference:Huawei HCIE-Datacom Guide – VLAN Security and User Isolation Technologies