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

The Time-To-Live (TTL) field in MPLS is essential for preventing infinite loops and enhancing security.

MPLS TTL Field Functionality:

It prevents packets from circulating indefinitely in the MPLS network.

It allows traceroute (tracert) to identify MPLS hops when TTL propagation is enabled.

Explanation of Correct Answers:✅ B. The processing of IP TTL copy hides the LSR in an MPLS domain, improving security.

If TTL propagation is disabled, MPLS routers do not decrease TTL, hiding internal LSRs from traceroute, enhancing security.

✅ C. MPLS provides two TTL processing modes:

Default Mode: The MPLS TTL copies the IP TTL value when an IP packet enters the MPLS network.

Uniform Mode: The ingress LER sets the MPLS TTL to 255, so it does not decrement.

✅ D. MPLS encapsulation in frame mode supports the TTL field, while cell mode does not.

Frame Mode (Ethernet, PPP, etc.) supports TTL.

Cell Mode (ATM/MPLS) does not support TTL.

Incorrect Answer Explanation:❌ A. If TTL copy is disabled, users can use the tracert function to view MPLS hops.

Wrong! If TTL propagation is disabled, tracert cannot see LSRs inside the MPLS core network.

Reference from Huawei HCIE-Datacom Documentation:

Huawei MPLS Technology Guide – TTL Field & Loop Prevention

HCIE-Datacom MPLS VPN Configuration Guide – Traceroute in MPLS Networks

Comprehensive and Detailed Explanation:

✔ Fit APs require additional configurations before going online, such as:

AP authentication and onboarding through DHCP Option 148 or manual registration.

Firmware upgrade and provisioning from iMaster NCE-Campus.

Policy enforcement and VLAN assignment.

Since additional steps are required, Fit APs do not go online immediately, making the statement FALSE.

???? Reference: Huawei HCIE Datacom – AP Registration and Authentication

Understanding the Network Scenario:

R2 is the boundary router between OSPF and IS-IS.

OSPF and IS-IS do not automatically redistribute routes between each other.

R4 ' s loopback (10.1.4.4/32) exists in the IS-IS domain.

To allow R1 (OSPF) to reach R4’s loopback, R2 must redistribute IS-IS routes into OSPF.

Why Option C Is Correct (✅)

✔ default-route-advertise in OSPF on R2:

This advertises a default route into the OSPF domain, allowing OSPF routers (R1, R3) to forward unknown traffic to R2.

Since IS-IS routes are not automatically injected into OSPF, this ensures R1 can reach R4.

✔ IS-IS Already Has Routes to OSPF

IS-IS routers (R3, R4) already learn routes from OSPF via R2 (assuming route redistribution is properly configured).

No need to run default-route-advertise in IS-IS.

Why Other Options Are Incorrect (❌)

❌ A. Run default-route-advertise in both OSPF and IS-IS views on R2

Unnecessary in IS-IS. The IS-IS domain already learns OSPF routes from R2 via redistribution.

Only OSPF needs a default route to forward unknown traffic to R2.

❌ B. No configuration is required

Incorrect, because OSPF does not automatically learn IS-IS routes.

A default route or redistribution is needed for R1 to reach R4.

❌ D. Run default-route-advertise only in the IS-IS view on R2

Incorrect, because IS-IS already has routing information from OSPF.

The issue is with OSPF not learning IS-IS routes, so the command needs to be in OSPF view.

???? Reference: Huawei HCIE Datacom – OSPF and IS-IS Route Redistribution and Interoperability

???? R1 – Headend

It receives a normal IPv6 packet from CE1.

It inserts the SRH (Segment Routing Header) with segment list.

Therefore, R1 is the Headend.

Huawei Reference:

“The SRv6 headend node receives a normal IPv6 packet and inserts an SRH, becoming the source of the SR path.”

(Source: HCIE-Datacom V1.0 – SRv6 Fundamentals)

???? R2 – Transit Node

R2 simply forwards the SRv6-encapsulated packet.

It does not process any segment SID.

Hence, R2 is a Transit node.

“Transit nodes in SRv6 just forward packets based on the active segment in the IPv6 destination address without processing SRH.”

(Source: HCIE-Datacom Study Guide – SRv6 Node Roles)

???? R3 – Endpoint

The first SID in SRH is FC03::3, which belongs to R3.

R3 processes the SID, pops it, and forwards the packet to the next segment FC04::4.

Thus, R3 is an Endpoint for one segment.

???? R4 – Endpoint

The final destination SID in the SRH is FC04::4, which belongs to R4.

R4 performs the final End behavior, handling the payload.

So, R4 is also an Endpoint.

Virtual Networks in Huawei CloudCampus Solution:

Virtual networks (VNs) are segmented based on services (e.g., IoT, Guest Wi-Fi, Enterprise Wi-Fi).

Each VN has its own routing and forwarding instance (VRF).

Isolation Between Virtual Networks:

By default, different virtual networks are isolated.

If inter-VN communication is required, it must be manually configured using policy-based routing (PBR), inter-VRF routing, or firewall policies.

Reference from Huawei HCIE-Datacom Documentation:

Huawei CloudCampus Solution Guide – Virtual Networks and Segmentation

HCIE-Datacom Training Material – Policy-Based Inter-VN Communication

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)

Since both IPv4 and IPv6 peer addresses are listed, it confirms that both IPv4 and IPv6 IS-IS neighbor relationships are established between R4 and ee8c.a0c2.baf3.

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

Understanding Huawei’s Free Mobility Solution

Huawei’s Free Mobility solution is designed to ensure that users can seamlessly access the network regardless of their physical location while maintaining consistent policies.

???? Key Components in Free Mobility Solution:

1️⃣ iMaster NCE-Campus (Answer A - Core Role)

Manages network policies & user access.

Implements centralized policy control & orchestration.

2️⃣ Policy Enforcement Device (Answer B - Core Role)

Ensures that user policies (such as QoS, security, VLANs) are applied dynamically.

Typically a switch or gateway enforcing access control.

3️⃣ Policy Control Device (Answer D - Core Role)

Stores and dynamically assigns policies based on user role & device type.

Works closely with iMaster NCE-Campus.

???? Why is C (Authentication Device) NOT a Core Role?

❌ Authentication devices (such as a RADIUS or AAA server) are not a core component of Huawei’s Free Mobility solution.

They are part of the broader network security framework but not mandatory for Free Mobility.

Real-World Application:

Used in enterprise & campus networks where employees, guests, and IoT devices need seamless access while maintaining security policies.

✅ Reference: Huawei HCIE-Datacom Guide – Free Mobility Architecture & Policy Management

The command output shows:

* > i before both networks, which means these routes are the preferred routes (*) and are learned via internal BGP (i).

Two networks are listed: 3002::3 and 3002::4, which means R1 does have these two routes in its BGP IPv6 routing table.

For 3002::4, the path origin shows 65001 i, which means this route originated from AS 65001 and was learned through IBGP.

The AS Path attribute is only shown for 3002::4, but both routes are clearly present.

Therefore, the correct conclusion is:

D. R1 has routes 3002::3/128 and 3002::4/128.

Understanding HTTP/1.1 Response Structure

???? What is an HTTP Response?

The response is sent from the server to the client after processing an HTTP request.

The structure follows a standardized format:

Elements of an HTTP/1.1 Response:

✅ A. Status Line → Contains protocol version, status code, and reason phrase.

✅ B. Response Body → Contains HTML, JSON, XML, or other content.

✅ C. Response Header → Provides metadata about the response (e.g., Content-Type, Server).

✅ D. Empty Line → A blank line separates headers from the response body.

Example of an HTTP/1.1 Response:

HTTP/1.1 200 OK

Date: Sat, 08 Mar 2025 14:00:00 GMT

Server: Apache/2.4.41 (Ubuntu)

Content-Type: text/html; charset=UTF-8

< html >

< body >

< h1 > Welcome to Huawei Datacom < /h1 >

< /body >

< /html >

Why is the Answer A, B, C, D?

✅ An HTTP response includes a status line, headers, an empty line, and a response body.

Real-World Application:

Web Application Debugging: Helps developers analyze server responses.

API Security: Validates response headers to prevent injection attacks.

✅ Reference: Huawei HCIE-Datacom Guide – HTTP Protocol and Response Headers