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

Comprehensive and Detailed In-Depth Explanation:

In MPLS (Multi-Protocol Label Switching), thelabel retention modedetermines how an LSR (Label Switching Router) handles labels received from its neighbors:

Liberal Mode:

An LSRretains all labels distributed by its neighbors, not just the labels from the next-hop LSR.

This approachensures faster convergencebecause the LSR does not need to request new labels if the next hop changes.

Itdoes not save memory or label space, as it stores more labels than strictly necessary.

Conservative Mode:

An LSRonly retains labels from its next-hop neighbors, saving memory and label space.

StatementsCandDare correct because they accurately describe liberal mode.

StatementsAandBare incorrect because they describe conservative mode.

Option B is incorrect because it falsely states that EBGP cannot be configured on Spoke-PE or Spoke-CE if the Hub-CE and Hub-PE run IGP. In reality, EBGP can still be used between Spoke sites and PE devices, regardless of the protocol between the Hub PE and CE. EBGP is often used for PE-CE communication, including in Hub-and-Spoke architectures.

Exact Extract - Huawei HCIE-Datacom VPN Section:

“In Hub&Spoke deployments, EBGP can be deployed between Spoke-CE and Spoke-PE. The choice of routing protocol between Hub-CE and Hub-PE does not limit this.”

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.

PQ (Priority Queuing) ensures low-latency services like voice and video are prioritized.

WFQ (Weighted Fair Queuing) fairly allocates remaining bandwidth to services like FTP.

Option B provides a balanced approach: guarantees for voice/video via PQ, and fairness for FTP via WFQ.

Exact Extract - Huawei HCIE-Datacom QoS Module:

“Voice and video traffic should be handled by PQ to minimize delay and jitter. Non-critical services such as FTP should be placed in WFQ queues to ensure bandwidth fairness.”

Understanding the Command Components:

This is aHuawei CLI commandused fordiagnosing connectivitywithin aVPN instancein an MPLS network.

ping -aX→ Specifies thesource IP address(X) of the ping packets.

-cY→ Specifies thenumber of ICMP Echo Request packetsto send (Y).

-sZ→ Defines thesize (in bytes) of each ICMP Echo Requestpacket (Z).

-vpn-instance M→ Specifies theVPN instance (VRF) Mto which the ping packets belong.

Why are all options correct?

✅A. The source IP address of the ping packets is X.

The -aX optionforces the ping to originate from IP Xinstead of the default interface IP.

✅B. The ping packets belong to VPN instance M.

The -vpn-instance M optionensures the ping is sent within VPN instance M, allowing verification ofMPLS L3VPN routing.

✅C. During the ping operation, the quantity of ICMP Request packets is Y.

The -cY parameter sets thenumber of ICMP Echo Requeststo be sent, making Y the total count.

✅D. The size of each ICMP Request packet for the ping operation is Z bytes.

The -sZ parameterdefines packet size, helping to testMTU (Maximum Transmission Unit)issues.

Real-World Application:

Verifying MPLS VPN connectivity:Ensure customer networks are reachable withinseparate VRFs.

Testing MTU & fragmentation:Using -sZ, operators can check ifpacket fragmentationoccurs.

Debugging asymmetric routing issues:By forcing -aX, engineers can trace return paths.

✅Reference:Huawei HCIE-Datacom Official Guide – MPLS VPN Troubleshooting & Ping Options

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.

✅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

✅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

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.”

802.1X Authentication Overview

802.1X is aport-based authentication mechanismused for secure network access control. It involves:

EAPoL (Extensible Authentication Protocol over LAN) communicationbetween theclient (supplicant) and the switch (authenticator).

RADIUS communicationbetween theauthenticator and the authentication server (AAA server).

✅A. 802.1X authentication uses EAPoL to exchange authentication information.

EAPoL (Extensible Authentication Protocol over LAN)is used to send authentication packets overEthernet (IEEE 802.3)networks.

✅B. In EAP termination mode, the network device terminates EAP packets and re-encapsulates them into RADIUS.

The switchacts as an authentication proxybyterminating EAP sessions and converting authentication information into RADIUS format.

✅C. EAPoL is for wired (802.3), EAPoW is for wireless (802.11).

EAPoL (EAP over LAN) is used in wired Ethernet networks.

EAPoW (EAP over Wireless) is used in Wi-Fi (802.11) networks.

✅D. In EAP relay mode, EAP packets are encapsulated into RADIUS using EAPoR (EAP over RADIUS).

The switchdoes not terminate the EAP sessionbut insteadforwards EAP messages to the AAA server inside RADIUS packets.

Reference from Huawei HCIE-Datacom Documentation:

Huawei 802.1X Configuration Guide – EAPoL, EAPoW, and EAPoR

HCIE-Datacom Training Material – AAA Authentication Modes

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.”