Free Huawei H12-891_V1.0 Practice Exam with Questions & Answers | Set: 9

Huawei AR routers used as egress gateways in CloudCampus solutions support multiple onboarding and deployment methods, including:

DHCP Option 148-based auto-deployment

Web-based management

CLI-based deployment and configuration (also supported)

So, the statement is incorrect—CLI-based deployment is supported.

Exact Extract - Huawei CloudCampus AR Router Deployment Guide:

“AR series routers support multiple deployment methods including CLI, DHCP Option 148, and web-based registration.”

InMPLS VPN, packets are forwarded usingtwo labels:

Outer label (Transport Label)– Used by the MPLS backbone for forwarding.

Inner label (VPN Label)– Used by theegress PEto identify the correct VPN instance.

Explanation of Correct Options:

✅A. The egress PE sends the data packet to the correct VPN based on the inner label.

Theinner label is assigned by the egress PEand determines the final destination VPN instance.

✅B. The penultimate hop removes the outer label before forwarding the data packet to a peer egress PE.

Penultimate Hop Popping (PHP)occurs when thesecond-to-last router(P router) removes the outer MPLS label before forwarding to theegress PE.

This reduces theprocessing overheadon the egress PE.

✅D. The penultimate-hop device receives a packet with an outer label.

Theouter label is used to forward the packet across the MPLS backbone.

Before reaching the egress PE, thepenultimate router still has the outer labeland processes it.

Incorrect Option:

❌C. The IP data packet received by the egress LSR is without labels.

This isincorrectbecause theinner label (VPN label) is still presentwhen the packet reaches the egress PE.

Only theouter labelis removed by PHP, not the inner VPN label.

Reference from Huawei HCIE-Datacom Documentation:

Huawei MPLS VPN Configuration Guide – Label Processing

HCIE-Datacom MPLS Traffic Engineering and PHP Mechanism

Huawei iMaster NCE-Campus MPLS VPN Implementation Guide

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

6PE (IPv6 Provider Edge over MPLS) vs. 6VPE (IPv6 VPN Provider Edge over MPLS VPNs)

6PE (IPv6 over MPLS without VPNs):

Uses global IPv6 routingover MPLS.

No VPN instances (VRFs) are created on PEs.

IPv6 addresses cannot be reusedacross different CEs because all traffic is routed using a single global table.

6VPE (IPv6 over MPLS with VPNs):

Uses MPLS VPN (VRF instances) to provide IPv6 VPN services.

VPN instances (VRFs) are created on PEsto separate customer networks.

IPv6 addresses of CEs can be reusedin different VPN instances because each VRF maintains separate routing tables.

Correct Answer Explanation:

✅C. In 6VPE networking, IPv6 addresses of a CE can be reused.

Sinceeach VPN instance (VRF) maintains its own IPv6 routing table, IPv6 addresses of CEscan be reused across different VPNs.

Incorrect Answer Explanations:

❌A. In 6PE networking, VPN instances need to be created on PEs.

Wrong!6PEdoes not use VPN instances (VRFs); it relies on a global IPv6 routing table.

❌B. In 6PE networking, IPv6 addresses of a CE can be reused.

Wrong!Since 6PE uses asingle IPv6 global routing table, IPv6 addressescannot be reused.

❌D. In 6VPE networking, no VPN instance needs to be created on PEs.

Wrong!6VPErequires VPN instances (VRFs) on PEsto separate customer traffic.

Reference from Huawei HCIE-Datacom Documentation:

Huawei MPLS VPN Configuration Guide – 6PE and 6VPE Deployment

HCIE-Datacom Training Material – IPv6 MPLS Solutions

Comprehensive and Detailed In-Depth Explanation:

Prefix Segment:

Represents adestination prefixin the network.

APrefix SID (Segment Identifier)is a globally unique SID that maps to anIP prefixand is within theSRGB (Segment Routing Global Block)range.

Therefore,Cis correct.

Ais incorrect because a prefix SIDis within the SRGB range, not out of it.

Adjacency Segment:

Represents alink (adjacency)between two nodes.

AnAdjacency SIDislocally significantand typically allocated from theSRLB (Segment Routing Local Block)range.

It uniquely identifies a link between nodes in thesource node’s local routing table.

Therefore,Dis correct, whileBis incorrect because an adjacency SID is not necessarily an offset within the SRGB.

✅A. encoding: indicates the character set encoding format. Currently, only UTF-8 encoding is supported.

UTF-8 is the default and only supported character encoding in NETCONF XML.

✅B. /: indicates the end of the current tag.

In XML, closes an element, defining the end of a structure.

✅C.

The <?xml linedeclares an XML documentand its version/encoding.

✅D. ?>: indicates the end of an instruction.

Closes theXML declaration.

Reference from Huawei HCIE-Datacom Documentation:

Huawei NETCONF Development Guide – XML Formatting Rules

HCIE-Datacom Training Material – Understanding XML in Network Automation

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

IGP Metric Design in Enterprise WANs

In anenterprise bearer WAN, routingmetrics determine path selection. Theaggregation layerconnects multiple access-layer devices to the core network, so it should have alower metricto:

✅Ensure traffic is forwarded through higher-capacity aggregation links instead of lower-bandwidth access links.

✅Optimize traffic flow, reduce congestion, and improve network efficiency.

✅Enhance reliability by preferring more stable aggregation links.

IGP Routing Protocols Considerations:

OSPF: Lower cost values indicate preferred paths.

IS-IS: Lower link metrics result in preferred forwarding paths.

Reference from Huawei HCIE-Datacom Documentation:

Huawei IGP Design Guide – Enterprise WAN Routing Optimization

HCIE-Datacom Training Material – Metric Calculation and Path Selection in OSPF/IS-IS

Understanding 6PE & 6VPE in MPLS Networks

6PE (IPv6 Provider Edge) and 6VPE (IPv6 VPN Provider Edge) areMPLS-based solutionsthat allowIPv6 trafficto be carried over anMPLS IPv4 core networkwithout requiring the entire backbone to support IPv6.

????6PE (IPv6 over MPLS - No VPN)

Used forglobal IPv6 routingwithout VPN segmentation.

No need forVRFs (VPN Routing and Forwarding instances)because IPv6 prefixes arehandled natively.

????6VPE (IPv6 VPN over MPLS - Supports VPNs)

ExtendsMPLS L3VPNto supportIPv6 routing inside VPN instances.

UsesMP-BGP VPNv6to distribute IPv6 prefixes insideMPLS VPNs.

Why is the Answer TRUE?

✅No VRFs are required for 6PE:

6PEonly needs BGP labeled IPv6 routesin theglobal routing table.

IPv6 prefixes are carried usingMPLS labelswithout VPN segmentation.

✅VRFs are required for 6VPE, NOT for 6PE:

6VPE requires VPN instances (VRFs)forIPv6 L3VPNs, but6PE does not.

✅Real-World Application:

6PE is used in large ISP networkswhere IPv6 deployment is needed butwithout VPN separation.

6VPE is used for enterprise MPLS VPNs, allowing customers to haveisolated IPv6 routing tables.

✅Reference:Huawei HCIE-Datacom Guide – MPLS IPv6 Transition Technologies (6PE & 6VPE)