H12-891_V1.0 Exam Dumps - Huawei HCIE-Datacom Questions and Answers

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

Correct Order of Steps:

1️⃣Network planning

2️⃣Site design

3️⃣Device management

4️⃣Fabric management

5️⃣VN (Virtual Network) management

6️⃣Service deployment

Understanding the iMaster NCE-Campus Deployment Process

????iMaster NCE-Campus is Huawei’s AI-driven network automation and management platform for campus networks.

????The deployment follows a structured sequence to ensure a fully operational network.

Detailed Explanation of Each Step:

✅1️⃣Network Planning(First Step)

Defines the overallnetwork architecture, topology, and business requirements.

DeterminesWAN, LAN, and WLAN coveragefor the campus.

EnsuresIP addressing, VLANs, and security policiesare planned.

✅2️⃣Site Design(Second Step)

Createssite layoutsand determinesdevice placement(switches, APs, routers).

Definespower, cabling, and uplink requirementsfor optimal connectivity.

✅3️⃣Device Management(Third Step)

Onboards network devices (e.g., switches, APs, firewalls) into iMaster NCE-Campus.

Configuresinitial settingssuch asIP addresses, interfaces, and SNMP settings.

Ensuresdevices are registered and reachablein the management platform.

✅4️⃣Fabric Management(Fourth Step)

EstablishesVXLAN-based network fabricforautomated Layer 2/3 connectivity.

ConfiguresEVPN/VXLAN overlays, VTEPs, and underlay routing.

✅5️⃣VN (Virtual Network) Management(Fifth Step)

Definesvirtual networks (VNs) for different departments, tenants, or services.

ConfiguresQoS, ACLs, and network segmentation policies.

✅6️⃣Service Deployment(Final Step)

Activatesnetwork services like DHCP, security policies, and application access.

Ensures thatend-user connectivity and application traffic policies are in place.

Why Is This the Correct Order?

✅Each step builds upon the previous one, ensuring a smooth and structured deployment process.

✅Service deployment comes last because it finalizes user access and application connectivity.

Real-World Application:

Enterprise Campus Networks:Deployssecure, scalable campus connectivity with AI-based automation.

University Campuses & Smart Cities:UsesSDN-driven network segmentation and automationto simplify operations.

✅Reference:Huawei HCIE-Datacom Guide – iMaster NCE-Campus Deployment & Automation

Comprehensive and Detailed Explanation:

Inter-AS MPLS L3VPN Option BrequiresASBRs to exchange VPNv4 routesusingeBGPwith label information.

Analysis of Inter-AS VPN Solutions:

Option B uses eBGP to exchange labeled VPNv4 routes between ASBRs but does not require MPLS between ASBRs.

Option A does not exchange VPNv4 routes over ASBRs (uses IP routing instead).

Option C uses MP-BGP and requires full MPLS between ASBRs.

Since Option B requires ASBRs to exchange VPNv4 routes, the correct answer is B.

????Reference: Huawei HCIE Datacom – MPLS Inter-AS VPNs

Intra-Area-Prefix-LSA (Type 9) is used in OSPFv3 to carry IPv6 prefix information for a router or network and is flooded within the area.

Link-LSA (Type 8) is only sent on the local link and is not flooded throughout the area.

Inter-Area-Prefix-LSA (Type 3) and Inter-Area-Router-LSA (Type 4) are also flooded within an area but originate from ABRs, typically for cross-area route advertisement.

That said, Intra-Area-Prefix-LSA is specifically flooded within an area, matching the context of the question directly.

Exact Extract - Huawei HCIE-Datacom OSPFv3 Module:

“Intra-Area-Prefix-LSAs are flooded within the area and advertise the IPv6 prefixes associated with router and network LSAs.”

Comprehensive and Detailed Explanation:

The IS-IS peer output shows:

IPv4 Peer Address:10.1.34.1

IPv6 Peer Address:FE80::2E0:FCFF:FE98:2576

MT IDs (Multi-Topology) Supported:0 (IPv4), 2 (IPv6)

Sinceboth IPv4 and IPv6 peer addressesare listed, it confirms thatboth IPv4 and IPv6 IS-IS neighbor relationships are establishedbetweenR4 and ee8c.a0c2.baf3.

????Reference:Huawei HCIE Datacom – IS-IS Multi-Topology Support

Understanding SR-MPLS Label Calculation

SR-MPLS usesSegment Routing Global Block (SRGB)andPrefix SIDsto assign labels dynamically. TheMPLS labelfor a node’s loopback interface is calculated as follows:

MPLS Label=SRGB Base+Prefix SID Index

Where:

SRGB Base=20000(as given in the figure)

Prefix SID Index=30(configured for R3’s Loopback1)

Label Calculation:

20000+30=20030

Thus, theMPLS label corresponding to the loopback1 interface of R3 is 20030.

Why the Answer is 20030?

✔The SRGB defines the base label range.

✔Each router is assigned a unique Prefix SID index.

✔The label is dynamically computed by adding the Prefix SID Index to the SRGB Base.

Why Other Numbers Are Incorrect?

❌Any value outside the range 20000-21000

Would be incorrect because it must be withinR3’s SRGB range.

❌Using the Prefix SID Index directly (30)

Incorrect becauseMPLS labels are not assigned directly using Prefix SIDs; they are computed using the SRGB.

????Reference:Huawei HCIE Datacom – SR-MPLS Label Calculation and SRGB

IS-IS (Intermediate System to Intermediate System) protocolhas a limit on the size ofLink-State PDUs (LSPs).

Why Fragmentation?

LSPs contain routing and topology information.

If the LSPexceeds the maximum size, fragmentationallows the device to store and forward more routesby breaking them into smaller LSPs.

Key Point:IS-ISfragmentation is essentialin large-scale networks where routing tables grow beyond the default LSP size limit.

✅Reference:Huawei HCIE-Datacom Guide - IS-IS Protocol and Route Scaling

BGP in Huawei SD-WAN

Huawei SD-WAN usesBGP (Border Gateway Protocol) as the primary routing protocolto exchange VPN routes between Customer Premises Equipment (CPEs) and the controller.

✅Why BGP is Used in SD-WAN?

Scalability: BGP can handle a large number of VPN routes.

Policy-Based Routing: BGP allowstraffic engineering and policy controlacross SD-WAN tunnels.

Multiprotocol Support: Huawei SD-WAN usesMP-BGP to exchange IPv4, IPv6, and VPNv4 routes.

Comprehensive and Detailed Explanation:

IP Source Guard (IPSG)is aLayer 3 security featureused to protect againstIP address spoofingby filtering packets based onbound IP-MAC mappings.

Correct Statements:✔IPSG is a Layer 3 filtering mechanismthat checks if the source IP address of a packet matches thelearned or configuredbindings (Option B).✔IPSG prevents unauthorized IP address changesby enforcing binding rules (Option C).✔IPSG defends against IP spoofing attacksby dropping packets fromunauthorized sources(Option D).

Incorrect Statement:❌Option A is incorrectbecause IPSGdoes not send alarms to an NMSwhen an invalid packet is detected. Instead, itdropsthe packet.

Thus, the correct answer isA.

????Reference:Huawei HCIE Datacom Security Guide - IP Source Guard (IPSG)

Understanding VXLAN and ARP Suppression in BGP EVPN

VXLAN (Virtual Extensible LAN) is used toextend Layer 2 networks over Layer 3 infrastructure.

VXLAN uses VTEPs (VXLAN Tunnel Endpoints) to encapsulate and forward Layer 2 traffic.

BGP EVPN (Ethernet VPN)is used forMAC/IP address learning and distributionacross VXLAN networks.

How ARP Request Forwarding Works in This Scenario?

1️⃣ARP Broadcast Suppression Enabled (VXLAN Optimized Forwarding)

SinceARP broadcast suppressionis enabled onVTEP1, theARP request is not flooded.

Instead, VTEP1checks its EVPN learned databaseto findPC2’s MAC address (MAC C).

2️⃣VTEP1 Encapsulates the ARP Request

VTEP1encapsulates the ARP request in a VXLAN packetand sends it toVTEP2.

Theoriginal ARP frame inside the VXLAN tunnel still has:

Source MAC:MAC A(PC1's MAC)

Destination MAC:MAC C(PC2's MAC, learned via EVPN)

3️⃣VXLAN Outer Headers

Theouter VXLAN headeruses:

Source IP:1.1.1.1 (VTEP1)

Destination IP:2.2.2.2 (VTEP2)

VNI (VXLAN Network Identifier):200(BD 20)

4️⃣VTEP2 Receives and Forwards the ARP Request

VTEP2 decapsulates the VXLAN packetand forwards theoriginal ARP requesttoPC2 (MAC C).

This ensures thatonly the intended receiver (PC2) gets the ARP request, preventing unnecessary broadcast flooding.

Why the Answer is MAC C?

✅B. MAC C is Correct

Thedestination MAC of the inner data frameisPC2’s MAC (MAC C).

This is becauseVTEP1 forwards the ARP request directly to VTEP2, which then forwards it to PC2.

Why Other Answers Are Incorrect?

❌A. MAC B (Incorrect)

MAC B is VTEP1’s MAC address, which is used in theouter VXLAN header, not in the inner Ethernet frame.

❌C. MAC A (Incorrect)

MAC A is the source MACof the ARP request (PC1), not the destination.

❌D. MAC D (Incorrect)

MAC D is not mentioned in the topology, so it is irrelevant.

????Reference:Huawei HCIE Datacom – VXLAN BGP EVPN and ARP Suppression