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

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

Comprehensive and Detailed In-Depth Explanation:

In VXLAN encapsulation, the data frame is encapsulated as follows:

Original Ethernet Frame:The data packet to be encapsulated.

VXLAN Header:Contains the VXLAN Network Identifier (VNI) and other information.

UDP Header:VXLAN usesUDP (User Datagram Protocol)to transport the encapsulated data over an IP network.

Outer IP Header:Provides the source and destination IP addresses of the VTEPs.

Therefore, theUDP header(C) isencapsulated between the outer IP header and the VXLAN header.

Comprehensive and Detailed Explanation:

✔Breakdown of the NETCONF Configuration:

✅(B) Huawei-YANG Model Used:The namespace contains http://www.huawei.com/netconf/vrp/huawei-vlan, indicatingHuawei 's YANG model.

✅(C) VLAN 10 is Created:10 confirms VLAN 10 is configured.

✅(D) Merge Operation Used:The xc:operation="merge" tag ensures changes aremergedrather than replacing the entire config.

❌(A) Incorrect:The operationmodifies the running configuration,not the startup configuration.

????Reference:Huawei HCIE Datacom – NETCONF Configuration Management

TheMPLS headerconsists of:

Label (20 bits)– Label value used for forwarding.

EXP (3 bits)– QoS field (Class of Service).

S bit (1 bit)– Bottom-of-Stack indicator.

TTL (8 bits)–Time-to-Live, similar to the TTL field in the IP header.

Function of TTL in MPLS:

It is used toprevent infinite loops.

Every LSRdecrementsthe TTL by 1.

When TTL reaches0, the packet isdiscarded.

This mirrors the behavior of IP TTL and ensures loop prevention in MPLS networks.

Correct answer: D. This field is used to prevent packet forwarding loops, similar to the TTL field in an IP header.

Understanding VGMP (Virtual Gateway Management Protocol)

????What is VGMP?

VGMP (Virtual Gateway Management Protocol) is used in Huawei firewalls to manage hot standby (HRP - Hot Standby Routing Protocol).

Ensures that theactive and standby firewalls synchronize their statesfor high availability.

????How Does VGMP Work?

TheActive and Standby firewalls exchange VGMP packetsto maintain state synchronization.

These packets are encapsulatedwithin UDPfor transport.

Thedefault UDP port for VGMP is 512.

Why is the Answer 512?

✅Huawei firewalls use UDP port 512 by default for VGMP communication.

✅This ensures that VGMP heartbeats and synchronization messages are correctly processed.

Real-World Application:

Enterprise Firewalls:VGMP ensuresfailover between active and standby firewalls.

Carrier-Grade Firewalls:UsesVGMP with HRP to achieve zero-downtime firewall redundancy.

✅Reference:Huawei HCIE-Datacom Guide – VGMP and HRP High Availability Mechanisms

Analyzing the Routing Table Output:

The command display ipv6 routing-table protocol isis showsall IPv6 routes learned via IS-IS.

The output shows"Summary Count: 6", meaning R1 hassix IS-IS IPv6 routes.

Explanation of Correct Answers:✅A. R1 has six IS-IS IPv6 routes.

The "Summary Count: 6" confirms thatsix IS-IS IPv6 routes existin R1's routing table.

✅C. IS-IS IPv6 must have been enabled on GigabitEthernet0/0/1 of R1.

Theinterface GigabitEthernet0/0/1is listed as thenext-hop, meaning IS-IS IPv6 must beenabled on that interface.

✅D. R1 is not a Level-1 device.

The protocol is listed as"ISIS-L2", indicating that R1 is anIS-IS Level-2 (backbone) router,not a Level-1 router.

Incorrect Answer Explanation:❌B. R1 does not have IS-IS IPv6 routes.

Wrong!The output clearlyshows six IS-IS IPv6 routes, proving this statement false.

Reference from Huawei HCIE-Datacom Documentation:

Huawei IPv6 Routing Protocols Guide – IS-IS for IPv6

HCIE-Datacom Routing & Switching Training – IS-IS L1 & L2 Operations

Huawei IS-IS Configuration Guide – IPv6 Route Management

InMPLS Traffic Engineering (TE),Label Switched Paths (LSPs)can be established:

Statically: Manual configuration.

Dynamically: Typically viaRSVP-TE.

Protocol roles:

RSVP-TE:Used to dynamically establish and signal TE LSPs→✅

OSPF / IS-IS: Act asIGP protocolsand provide TE-related link-state information (like bandwidth) butdo not establish LSPs themselves→❌

BGP: Used forroute advertisement, not forLSP setupin MPLS TE →❌

Correct answers: A, C, D

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.”

Comprehensive and Detailed Explanation:

✔MPLS labels in SR-MPLS are calculated using the SRGB (Segment Routing Global Block) baseand thePrefix-SID.

✔Label Calculation Formula:

MPLS Label=SRGB Base+Prefix-SID\text{MPLS Label} = \text{SRGB Base} + \text{Prefix-SID}MPLS Label=SRGB Base+Prefix-SID

✔Extracting Values from the LSDB:

SRGB Base:36000

Prefix-SID:300

✔Valid MPLS Labels:

36000 + 300 = 36300

40002 and 38002 fall within the SRGB range.

39002 is outside the expected range, making it theincorrect answer.

????Reference:Huawei HCIE Datacom – Segment Routing Label Calculation

DiffServ QoS model operates on per-hop behavior (PHB) and has these limitations:

A. ✅ Single-hop behavior; no end-to-end path awareness.

B. ✅ Cannot guarantee dedicated resources to individual users.

C. ✅ Does not address traffic bursts; congestion is still possible.

D. ✅ Queue limitations hinder fine-grained SLA assurance and deterministic delay.

Exact Extract – HCIE-Datacom QoS Section:

“DiffServ provides PHB without path-level control. It cannot guarantee SLA for individual users due to limited queuing mechanisms and lack of end-to-end visibility.”