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

VXLAN Inter-Subnet Routing with Symmetric IRB

VXLAN supports inter-subnet routing using Integrated Routing and Bridging (IRB). In symmetric IRB, both ingress and egress VTEPs perform Layer 3 forwarding to ensure efficient packet forwarding across subnets.

✅ A. Both the ingress VTEP and egress VTEP forward packets based on the Layer 3 forwarding table.

In symmetric IRB, both ingress and egress VTEPs perform Layer 3 lookup and forwarding.

The ingress routes packets before encapsulating them in VXLAN, and the egress performs another Layer 3 lookup to determine final delivery.

✅ D. When VTEPs forward inter-subnet user communication packets, the VNI carried in the VXLAN header is the L3VNI.

L3VNI (Layer 3 VXLAN Network Identifier) is used for inter-subnet routing between VXLAN segments.

✅ 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, < /tag > closes an element, defining the end of a structure.

✅ C. < ?: indicates the start of an instruction.

The < ?xml line declares an XML document and its version/encoding.

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

Closes the XML declaration.

Reference from Huawei HCIE-Datacom Documentation:

Huawei NETCONF Development Guide – XML Formatting Rules

HCIE-Datacom Training Material – Understanding XML in Network Automation

In Huawei’s CloudCampus Solution, VNs (Virtual Networks) are isolated by default for security purposes. To enable inter-VN communication, you must explicitly configure policies that allow traffic between different VNs.

The correct way to control and enable this communication is via routing policies, especially inter-VN routing policies on the core or border nodes.

Static routes or OSPF deployments are not sufficient or appropriate for policy-controlled VN communication in this context.

Correct answer: D. Deploy a routing policy

When selecting core devices for a WAN in enterprise networks, considerations typically include:

Service volume: Ensures the core device can handle expected traffic.

Physical location: Important for latency, redundancy, and network design.

Node quantity: Affects topology, scalability, and routing complexity.

Device naming conventions, however, are purely administrative and do not affect the functional selection of core devices.

Correct answer: A. Device naming conventions

Huawei SD-WAN supports various intelligent traffic steering mechanisms to optimize link utilization and balance network traffic across multiple links.

✅ D. Traffic bandwidth-based traffic steering

This method ensures that traffic is distributed across multiple links based on available bandwidth.

SD-WAN dynamically selects links based on their real-time bandwidth utilization, ensuring optimal performance and load balancing.

Comprehensive and Detailed In-Depth Explanation:

An NVE (Network Virtualization Edge) interface is responsible for connecting physical or virtual devices to a VXLAN network. It functions as the VTEP (VXLAN Tunnel Endpoint) and supports encapsulation and decapsulation of VXLAN packets.

Layer 2 VXLAN gateway (D) is used for intra-subnet communication, but the NVE interface is the actual point where traffic enters the VXLAN network.

Layer 3 VXLAN gateway (A) is used for inter-subnet communication.

VLANIF interface (C) is used for VLAN-based communication, not directly for VXLAN.

Therefore, the NVE interface (B) is the correct answer as it serves as the traffic ingress and egress point for the VXLAN network.

GRE (Generic Routing Encapsulation) supports encapsulation of many protocol types:

Supports IPv4 and IPv6 unicast encapsulation — ✅

Does not support IPv6 broadcast encapsulation. GRE doesn’t natively handle multicast or broadcast IPv6 traffic well — ❌

It is a lightweight tunneling protocol and relatively easy to deploy, placing minimal overhead on devices — ✅

Correct answer: C. GRE can encapsulate IPv6 broadcast packets — is incorrect.

The Loopback interface is not advertised by default in IS-IS, unless a specific command is used (like network entity with loopback settings or enabling it manually). In this case, the GE0/0/0 and GE0/0/1 interfaces are both UP, and have IS-IS L1/L2 enabled. These two interfaces qualify to advertise IS-IS routes.

Exact Extract - Huawei HCIE-Datacom V1.0 IS-IS Chapter

“By default, only physical interfaces in UP state and configured with IS-IS (L1, L2, or L1/L2) participate in IS-IS. Loopback interfaces must be explicitly advertised using route import policies.”

IS-IS Multi-Process:

Huawei devices support running multiple IS-IS processes simultaneously.

These processes are completely independent of one another: different LSDBs, interfaces, routing tables, etc.

Each process can be associated with a separate VPN instance, and a single VPN instance can be served by multiple IS-IS processes.

IS-IS Multi-Instance:

One IS-IS process can run multiple instances, typically used for multi-VPN scenarios.

However, Huawei ' s current implementation prefers one VPN per process for clarity and control.

Based on Huawei’s design:

A is incorrect — an IS-IS process can serve multiple VPNs in other vendors, but Huawei typically uses one process per VPN for clean separation.

B is correct — a VPN instance can be associated with multiple IS-IS processes.

C is incorrect in Huawei implementation context.

D is correct — IS-IS processes are independent.

Correct answers: B, D

IPsec (Internet Protocol Security) provides secure communication over IP networks through several essential functions. Let’s explain each function and its purpose:

1. Data Origin Authentication:

Description: The receiver verifies the identity of the sender.

Explanation:

This function ensures that the data received actually comes from the claimed source.

IPsec achieves this using IKE (Internet Key Exchange) and digital signatures.

The Authentication Header (AH) and Encapsulating Security Payload (ESP) support authentication.

Use Case: Verifying that a message claiming to be from a specific IP address is genuinely from that source.

2. Data Encryption:

Description: The sender encrypts the data, and the receiver decrypts the data.

Explanation:

Encryption ensures data confidentiality by transforming readable data (plaintext) into unreadable data (ciphertext).

Only the intended receiver with the correct decryption key can convert the ciphertext back to plaintext.

Common encryption algorithms used include AES (Advanced Encryption Standard) and DES (Data Encryption Standard).

Use Case: Protecting sensitive data transferred over public networks.

3. Data Integrity:

Description: The receiver verifies received data to determine whether the data has been tampered with.

Explanation:

Ensures that the data was not altered during transmission.

Uses cryptographic hash functions (e.g., SHA-1, SHA-256) to generate a message digest.

The digest is sent with the data and verified on the receiving side.

Use Case: Detecting any changes made to the data packet during transmission.

4. Anti-Replay:

Description: The receiver rejects duplicate data packets.

Explanation:

Prevents attackers from capturing packets and replaying them later.

Uses sequence numbers to detect replayed or duplicated packets.

The receiver keeps a sliding window of sequence numbers to compare incoming packets.

Use Case: Blocking malicious actors from sending previously intercepted packets to disrupt communication.

Why This Mapping Is Correct:

The functions and descriptions are aligned based on the core concepts of IPsec and the roles they play in ensuring secure data transmission.

Each function addresses a specific aspect of security: authentication, confidentiality, integrity, and replay protection.