H12-891_V1.0 Huawei HCIE-Datacom V1.0 Free Practice Exam Questions (2025 Updated)

Comprehensive and Detailed In-Depth Explanation:

TheiMaster NCE-IP controllerusesTelemetryto collect real-timedevice running statusinformation efficiently and with low latency.

Telemetry (A):Enables continuousdata streamingto the controller, including network performance and link state information.

Telnet (B):Used for manual device management and not suitable for automated data collection.

BGP-LS (C):Used fordistributing link-state information, but not for real-time performance data collection.

IS-IS (D):AnIGP protocol, not used for collecting device status.

SRv6 Policies can be:

Statically configured via CLI on routers.

Dynamically generated and delivered from a controller such as Huawei iMaster NCE for centralized path computation.

This dual approach allows flexibility in deployments.

Exact Extract – Huawei SRv6 Deployment Guide:

“SRv6 Policies can be locally configured or dynamically delivered via PCEP from the controller, enabling both static and SDN-based implementations.”

An IPsec Security Association (SA) includes the following critical components:

SPI (Security Parameter Index)

Destination IP address

Security Protocol (AH or ESP)

Encryption/Authentication algorithms

The Source IP address is not a defining parameter of an SA. SA is unidirectional and identified based on the SPI and destination address.

Exact Extract - Huawei Security Configuration Guide – IPsec Fundamentals:

“An SA is uniquely identified by the SPI, destination IP, and security protocol. The source address is not a determining factor in the SA.”

Infirewall hot standby (HRP - Hot Standby Routing Protocol) mode, certain data can be synchronized between the active and standby firewalls to ensure uninterrupted service.

Thefollowing data is backed up:

✅Server mapping table:Contains information about NAT mappings and other session mappings.

✅AAA user table (excluding the default user admin):Ensures that authenticated users do not need to re-authenticate in case of failover.

✅Session table:Ensures that existing connections remain active when switching to the standby firewall.

❌Dynamic MAC address table is NOT backed upbecause it is dynamically learned and not relevant to firewall session synchronization.

✅Reference:Huawei HCIE-Datacom Guide - Firewall HRP Synchronization

SSH (Secure Shell) is a protocol designed for secure remote access and is always built on TCP, typically on port 22. UDP is not supported for SSH, as it is connectionless and doesn't provide the required reliability and order.

Exact Extract – Huawei Security Protocol Fundamentals:

“SSH is a TCP-based protocol. It does not support UDP. TCP ensures session reliability and data integrity, which are critical for SSH.”

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.

SRv6 Instruction Naming Conventions

SRv6 (Segment Routing over IPv6)uses segment identifiers (SIDs) with specific functions, indicated byinstruction keywords:

✅A. T: Searches a specified routing table to forward packets.

T (Table Lookup)→ Performsa lookup in a specified routing tableand forwards packets accordingly.

❌B. M: Searches a Layer 2 forwarding table for unicast forwarding.

Incorrect!SRv6 does not use M for Layer 2 unicast forwarding.

✅C. V: Searches a VPN instance routing table to forward packets.

V (VPN Routing Table Lookup)→Performs a lookup in a VPN instance (VRF) tablefor forwarding.

✅D. X: Forwards packets through one or a group of specified Layer 3 interfaces.

X (Cross-connect forwarding)→Forwards packets via a specified Layer 3 interface or group of interfaces.

Reference from Huawei HCIE-Datacom Documentation:

Huawei SRv6 Configuration Guide – SRv6 SID Naming and Instruction Set

HCIE-Datacom Study Material – Segment Routing over IPv6 (SRv6) Functionality

In IPsec, a symmetric encryption algorithm (e.g., AES) is used for encrypting data due to its speed. To securely exchange the symmetric key between peers, asymmetric encryption algorithms (like RSA) are used.

This method ensures:

High performance (due to fast symmetric encryption)

Secure key exchange (asymmetric protection)

Exact Extract - Huawei HCIE-Datacom Guide – IPsec Encryption:

“IPsec uses symmetric algorithms to encrypt data for performance and asymmetric algorithms to securely exchange symmetric keys during IKE negotiation.”

Comprehensive and Detailed In-Depth Explanation:

Analyzing the output:

A. The device sends sampled data every second:Correct. Thesample interval is 1000 ms (1 second).

B. The subscription name is Sub1:Correct. Thesubscription nameis clearly shown asSub1.

C. The subscription mode is static subscription:Correct. Since theSub-stateisPASSIVE, it indicates astatic subscription.

D. The IP address of the device is 192.168.56.1:Incorrect. The IP address192.168.56.1shown in the output is thedestination IPwhere the telemetry data is sent, not the IP address of the device itself.

Network Slicing Using Channelized Sub-Interfaces and FlexE

Bothchannelized sub-interfacesandFlexE (Flexible Ethernet)are used fornetwork slicing, but they have differentapplication scenarios:

✅A. Channelized sub-interface is recommended for interfaces with bandwidth < 50 Gbit/s.

Channelized sub-interfacessplit a physical interfaceinto multiple logical sub-interfaces.

Best for lower-bandwidth links (<50 Gbit/s).

✅B. FlexE is recommended for 50GE and higher-rate interfaces.

FlexEdivides a high-bandwidth physical link(e.g.,100GE, 400GE) into multiple virtual slices.

Used in high-speed backbone and data center networks.

✅C. Only FlexE-based network slicing can be deployed across OTN devices.

FlexE is compatible with Optical Transport Network (OTN)and can be used for long-haul slicing across OTN.

❌D. Only channelized sub-interface-based network slicing can be deployed across MSTP devices.

Incorrect!While MSTP supports channelized interfaces,FlexE is not restricted to MSTP deployment.

Reference from Huawei HCIE-Datacom Documentation:

Huawei FlexE Technology Whitepaper – Network Slicing in Transport Networks

HCIE-Datacom Training Material – Channelized Sub-Interface and FlexE in Network Slicing

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.”

ForOSPF neighbors to reach Full state, they must exchangeLSAs (Link State Advertisements) properlyand synchronize their databases.

Possible Causes Preventing OSPF from Entering Full State:

✅A. A link works abnormally

If thephysical or Layer 2 linkis unstable,OSPF Hello packetsmay be lost, preventing the Full state.

✅B. The OSPF network types on both ends of the link are inconsistent

OSPF network types (Broadcast, P2P, NBMA, etc.) must matchon both ends.

Example: If one router isP2Pand the other isBroadcast, adjacency issues occur.

✅C. The router IDs of neighbors are the same

Router ID conflicts prevent OSPF adjacencies from forming.

Each router must have aunique Router ID.

✅D. The OSPF MTU values of interfaces on both ends of the link are different

If MTU settings do not match,OSPF Database Description (DD) packets may be dropped, preventing Full state.

Reference from Huawei HCIE-Datacom Documentation:

Huawei OSPF Configuration Guide – Troubleshooting OSPF Neighbor Issues

HCIE-Datacom Study Material – OSPF Adjacency and Route Synchronization

To analyze this question, let's break down the key concepts and the given LSDB (Link State Database) information from the figure:

Understanding the LSDB Output:

The output shows the OSPF LSDB on R2 with Router ID 10.1.123.2.

Area 0.0.0.0 (Area 0) is displayed along with several Link State Advertisements (LSAs) including Router LSAs, Network LSAs, and Summary LSAs.

Area 0.0.0.1 (Area 1) also displays Router LSAs and a Type 7 LSA (NSSA LSA) with Link-State ID 0.0.0.0.

An External LSA (Type 5) with Link-State ID 0.0.0.0 and AdvRouter 10.1.123.2 is also present.

Analysis of Each Option:

Option A: Area 1 is an NSSA.

Correct.

The presence of a Type 7 LSA (NSSA LSA) in the database indicates that Area 1 is configured as an NSSA (Not-So-Stubby Area).

NSSA allows the injection of Type 7 LSAs for external routes while blocking Type 5 LSAs from entering the area.

Option B: R2 translates Type 7 default route into Type 5 default route.

Correct.

In an NSSA, if an ABR (like R2) has the NSSA ASBR capability, it will convert Type 7 LSAs to Type 5 LSAs before injecting them into the backbone area (Area 0).

In the LSDB, we see both a Type 7 LSA (NSSA) and a corresponding Type 5 External LSA, confirming that R2 performs this translation.

Option C: R2 advertises the default route in the OSPF process.

Incorrect.

There is no indication that R2 itself is originating the default route.

The Type 7 LSA in Area 1 and the Type 5 LSA in Area 0 only indicate translation from another source, not R2 advertising it directly.

Option D: Area 1 does not have Type 3 LSAs. The possible cause is that R2 filters Type 3 LSAs in the outbound direction of Area 1.

Incorrect.

In an NSSA area, Type 3 LSAs (Inter-Area Prefix LSAs) are typically not generated for external routes.

The absence of Type 3 LSAs in Area 1 is due to the nature of NSSA itself rather than any filtering configured on R2.

A. The device sends sampled data every second→Correct, since sample interval is 1000ms = 1 second.

B. The subscription mode is static subscription→Correct, as shown by Sub state: PASSIVE. Passive indicates astatic subscription.

C. The IP address of the device is 192.168.56.1→Incorrect— this IP address is thedestination (telemetry collector),notthe device’s own IP.

D. The subscription name is Sub1→Correct, as per Sub name : Sub1.

Correct answer: C. The IP address of the device is 192.168.56.1— this is incorrect because it's actually the collector’s IP, not the device's.

Understanding BFD (Bidirectional Forwarding Detection)

BFDis ahigh-speed fault detection protocolused to monitor link failures inmilliseconds.

It operates atLayer 2 (Data Link Layer) and Layer 3 (Network Layer)to providefast convergence.

Why Can BFD Detect Failures in Milliseconds?

Useslightweight control packetsthat are exchanged between routers.

Works withOSPF, IS-IS, BGP, and MPLSto trigger fast convergence.

Detection time = (Transmit Interval) × (Detect Multiplier)

Example: If the interval is3msand the multiplier is3, failure detection takes9ms.

Why is the Answer TRUE?

✅BFD achieves millisecond-level detectionby sending rapid probe packets.

✅Used in high-availability networkswhere link failures must be detected inreal-time.

Real-World Application

Service Provider Networks:BFD improves network resilience by detecting link failuresfaster than traditional routing timers.

Enterprise WANs:Used inSD-WANsto switch paths dynamically.

MPLS Fast Reroute (FRR):Works withMPLS Traffic Engineeringfor near-instantaneous failover.

✅Reference:Huawei HCIE-Datacom Guide – BFD for Fast Link Failure Detection

BGP routing policiesallow administrators to:

Control incoming and outgoing routes.

Filter routes based onprefix, AS-PATH, communities, MED, next hop, etc.

Apply route maps, prefix lists, or filter policies during:

Route advertisement

Route reception

Route import/export into local RIB or VPN instance

This is a fundamental capability of BGP and is widely used in production environments for traffic engineering, route filtering, and policy-based routing.

Correct answer: A. TRUE

Understanding the Telemetry Output:

Dest-addr: 192.168.56.1→The destination IP address is 192.168.56.1.✅

Dest-name: Dest1→The destination group name is Dest1.✅

Protocol: gRPC→Data push uses the gRPC protocol.✅

Vpn-name: - (empty)→No VPN encapsulation is used.❌

Incorrect Answer Explanation:

❌C. "VPN encapsulation is used for data push"→Incorrect!

The Vpn-name field isempty, indicating thatVPN encapsulation is NOT enabled for telemetry data transport.

Reference from Huawei HCIE-Datacom Documentation:

Huawei Telemetry Configuration Guide – Destination and Data Push Methods

HCIE-Datacom Study Material – gRPC and Telemetry Data Streaming

Comprehensive and Detailed In-Depth Explanation:

Analyzing the output:

A. Key authentication is disabled for the tunnel:Correct. The output explicitly states"key disabled".

B. The destination IP address of the tunnel is 10.0.3.3:Correct. The output shows"destination 10.0.3.3".

C. The tunnel is a GRE tunnel:Correct. The output states"Tunnel protocol/transport GRE/IP".

D. Keepalive detection is enabled on the tunnel:Incorrect.The output clearly shows"keepalive disabled".

Therefore, the correct answer isDbecause the tunnel doesnot have keepalive enabled.