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

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IPsec (Internet Protocol Security) provides secure communication over IP networks by implementing multiple security functions.

✔Data Origin Authentication:

Ensures that the sender of the data is genuine and not impersonated.

Uses techniques such as HMAC (Hash-Based Message Authentication Code).

Correct Match:"The receiver verifies the identity of the sender."✅

✔Data Encryption:

Protects data confidentiality by encrypting packets using AES, 3DES, or other encryption algorithms.

Ensures that only the intended recipient can decrypt the data.

Correct Match:"The sender encrypts the data, and the receiver decrypts the data."✅

✔Data Integrity:

Ensures that data is not altered in transit.

Uses cryptographic hashes (e.g., SHA-256) to verify integrity.

Correct Match:"The receiver verifies received data to determine whether the data has been tampered with."✅

✔Anti-Replay:

Protects against packet replay attacks, where an attacker resends captured packets to disrupt communication.

Uses sequence numbers to detect and reject duplicate packets.

Correct Match:"The receiver rejects duplicate data packets."✅

????Reference:Huawei HCIE Datacom – IPsec Security Functions

Before performing anetwork cutover (migration or upgrade), it is essential to collectbaseline datato ensure that services operate normally before and after the change.

Importance of Pre-Cutover Information Collection:

Identifies Network Baseline– Helps comparepre-cutover and post-cutover performance.

Detects Hidden Issues– Ensures that no existing network issues interfere with the cutover process.

Prevents Service Interruptions– Ensures all dependent services are accounted for.

Provides Rollback Plan– If issues arise, administrators canrestore previous configurations.

Reference from Huawei HCIE-Datacom Documentation:

Huawei Network Change Management Guide – Pre-Cutover & Post-Cutover Best Practices

HCIE-Datacom Training Material – Service Assurance & Risk Analysis

In Huawei'sSRv6 instruction namingsystem, each letter keyword represents a specific forwarding behavior:

X (Cross): Forwards packets viaspecified Layer 3 interfaces→✅

M (MAC): SearchesLayer 2 forwarding tableforbroadcast/multicast,not unicast→❌

V (VPN): Searches theVPN routing table (VRF)for forwarding →✅

T (Table): Searches aspecific routing table (e.g., user-defined)→✅

Correct answers: A, C, D

Understanding IRB (Integrated Routing and Bridging) Forwarding in VXLAN

VXLAN (Virtual Extensible LAN) supportsLayer 2 and Layer 3 forwardingbetween Virtual Network Identifiers (VNIs).

IRB (Integrated Routing and Bridging)enables inter-subnet communication within a VXLAN fabric.

There aretwo modes of IRB forwarding:

Symmetric IRB

Asymmetric IRB

Why the Answer is "Symmetric" IRB Forwarding?

✔Ingress VTEP performs both Layer 2 and Layer 3 lookups:

Symmetric IRBrequiresboth ingress and egress VTEPsto performLayer 3 lookups.

Theingress VTEP (source gateway) performs a Layer 2 MAC lookup, then aLayer 3 lookupto find the destination VTEP.

Theegress VTEP (destination gateway) performs another Layer 3 lookupbefore forwarding the packet to the destination.

✔Asymmetric IRB does not perform two lookups at the ingress VTEP:

In Asymmetric IRB,the ingress VTEPperforms both Layer 2 and Layer 3 forwardingandsends a Layer 2 packet to the egress VTEP.

Theegress VTEP only does a Layer 2 lookup, not a Layer 3 lookup.

Since thequestion states that both L2 and L3 lookups occur at the ingress VTEP,asymmetric IRB is incorrect.

✔Why Symmetric IRB is More Common?

Scalability:Supportsany-to-any communicationacross VXLAN networks.

More Efficient Routing:UsesLayer 3 VXLAN encapsulation, ensuring efficient routing between VNIs.

????Reference:Huawei HCIE Datacom – VXLAN Symmetric and Asymmetric IRB Forwarding

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

Comprehensive and Detailed In-Depth Explanation:

In theiMaster NCE-Campusvirtualized network management platform, devices can be added using various methods:

A. In Batches:Correct. Devices can be added in bulk for efficient management.

B. By Device Role:Correct. Devices can be grouped and managed based on their role (e.g., access, aggregation, core).

C. By Device ESN (Electronic Serial Number):Correct. The ESN uniquely identifies the device within the system.

D. By Device Model:Incorrect. The platform does not use the device model as a primary criterion for adding devices. Instead, devices are typically added byrole, ESN, or batch operations.

In MPLS LDP, there are two types of sessions:

Direct LDP sessions: Established between directly connected LSRs using LDP Hellos over a link.

Remote LDP sessions (also called targeted LDP sessions): Established between non-directly connected LSRs. These requiremanual configurationof the remote peer.

In this scenario, SWA and SWC arenot directly connected, so aremote (targeted) LDP sessionmust be set up.

For a remote LDP session:

Youmust configure the remote peerusing the command:

[SWA-MPLS-LDP] targeted-peer x.x.x.x

Where x.x.x.x is theLSR ID of SWC(33.3.3.3 in this case).

The current configuration does not include this required step.

Thus, the correct statement is:

D. You need to create a remote peer and specify an LSR ID for the remote peer.

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

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

Comprehensive and Detailed Explanation:

✔The Best Protection Against MITM and Spoofing Attacks:

✅(D) Associating DHCP Snooping with IPSG (IP Source Guard) and DAI (Dynamic ARP Inspection)providescomplete protectionby:

Blocking rogue DHCP servers.

Preventing MAC/IP spoofing.

Ensuring only valid clients access the network.

✔Why Not Other Options?

❌(A) Configuring trusted/untrusted interfacesonly helpsblock rogue DHCP servers, but does not prevent spoofing.

❌(B) Limiting MAC address learningprevents MAC flooding, but does not stopMITM attacks.

❌(C) Checking the CHADDR field in DHCP Snoopinghelps detectspoofed requests, but does not block all MITM scenarios.

????Reference:Huawei HCIE Datacom – Security Mechanisms for Intranet Protection