For OSPF neighbors to reach Full state, they must exchange LSAs (Link State Advertisements) properly and synchronize their databases.

Possible Causes Preventing OSPF from Entering Full State:

✅ A. A link works abnormally

If the physical or Layer 2 link is unstable, OSPF Hello packets may 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 match on both ends.

Example: If one router is P2P and the other is Broadcast, adjacency issues occur.

✅ C. The router IDs of neighbors are the same

Router ID conflicts prevent OSPF adjacencies from forming.

Each router must have a unique 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

In MPLS LDP, there are two types of sessions:

Direct LDP sessions: Established between directly connected LSRs using LDP Hellos over a link.

Remote LDP sessions (also called targeted LDP sessions): Established between non-directly connected LSRs. These require manual configuration of the remote peer.

In this scenario, SWA and SWC are not directly connected, so a remote (targeted) LDP session must be set up.

For a remote LDP session:

You must configure the remote peer using the command:

[SWA-MPLS-LDP] targeted-peer x.x.x.x

Where x.x.x.x is the LSR ID of SWC (33.3.3.3 in this case).

The current configuration does not include this required step.

Thus, the correct statement is:

D. You need to create a remote peer and specify an LSR ID for the remote peer.

Let’s break it down:

A. ❌ Incorrect — Path computation can be done by both controller and ingress routers, not just the controller.

B. ✅ SR-MPLS extends IGP protocols (e.g., OSPF/IS-IS) for segment distribution, allowing smooth evolution.

C. ✅ Supports TI-LFA (Topology Independent Loop-Free Alternate) for fast failure recovery.

D. ✅ Through source routing, SR-MPLS integrates easily with applications for programmable path control.

Exact Extract – HCIE-Datacom Segment Routing Chapter:

“SR-MPLS supports distributed and centralized path computation, uses IGP extensions for deployment, and supports TI-LFA for FRR. It allows interaction with applications through programmable routing.”

IS-IS (Intermediate System to Intermediate System) protocol has a limit on the size of Link-State PDUs (LSPs).

Why Fragmentation?

LSPs contain routing and topology information.

If the LSP exceeds the maximum size, fragmentation allows the device to store and forward more routes by breaking them into smaller LSPs.

Key Point: IS-IS fragmentation is essential in large-scale networks where routing tables grow beyond the default LSP size limit.

✅ Reference: Huawei HCIE-Datacom Guide - IS-IS Protocol and Route Scaling

X = 0

Y = 0

Z = 1

Understanding MPLS Label Headers

???? What is MPLS (Multiprotocol Label Switching)?

MPLS is a high-performance forwarding technology that replaces IP lookups with label switching.

Packets are forwarded based on labels instead of destination IP addresses.

MPLS labels are stacked when passing through multiple hops.

???? MPLS Label Stack Structure

Each MPLS label has four fields:

Label – 20-bit identifier used for forwarding.

EXP (Experimental Bits / Traffic Class) – 3-bit field used for QoS (Quality of Service).

S (Bottom of Stack) – 1-bit flag that indicates whether this is the last (bottom) label in the stack.

TTL (Time-To-Live) – 8-bit field to prevent loops.

Understanding the EXP Fields (X, Y, Z) in the Figure

The image shows a packet with three MPLS labels.

Each label has an EXP field (X, Y, Z) representing the QoS bits.

By default, MPLS EXP bits are copied from the top label to lower labels unless modified by QoS policies.

If no QoS policy modifies the EXP bits, they remain the default value of 0.

The bottom label in the stack (Label 3) often has an EXP value of 1 to indicate specific QoS policies.

Why Are the Answers X = 0, Y = 0, Z = 1?

✅ X = 0 (Default EXP for Label 1, the top label in the stack).

✅ Y = 0 (EXP for Label 2, unchanged from the default value).

✅ Z = 1 (EXP for Label 3, indicating a QoS setting applied to the bottom label).

Real-World Application:

MPLS QoS (Quality of Service): EXP values determine packet priority in Service Provider networks.

Traffic Engineering (TE): MPLS labels guide packets through optimized paths, ensuring low-latency services.

Enterprise WAN Optimization: MPLS traffic is prioritized for critical applications like VoIP, Video Conferencing, and Cloud Services.

✅ Reference: Huawei HCIE-Datacom Guide – MPLS Label Stack and QoS EXP Field Processing

Comprehensive and Detailed Explanation:

On-premise mode refers to deploying the Huawei iMaster NCE-Campus controller within the enterprise network instead of using a cloud-based solution.

✔ Best suited for small and midsize campus networks that require:

Greater control over data security

Local network automation

No reliance on cloud connectivity

Since on-premise mode is recommended for small and midsize campus networks, the statement is TRUE.

???? Reference: Huawei HCIE Datacom – iMaster NCE Deployment Modes

Understanding NETCONF < config > Operation Attributes

???? What is NETCONF?

NETCONF (Network Configuration Protocol) is an IETF-standardized protocol for network automation.

Uses XML-based configuration transactions with < config > operations.

???? Common NETCONF < config > Operation Attributes:

✅ A. create → Adds new data but fails if it already exists.

✅ B. delete → Removes the specified data from the configuration datastore.

✅ C. merge → Updates existing data or creates it if it does not exist.

❌ D. remove (Incorrect Choice)

NETCONF does not support remove as an operation.

delete is the correct operation for removing data.

Why is the Answer A, B, C?

✅ NETCONF supports create, delete, and merge, but NOT remove.

Real-World Application:

SDN Controllers & Network Automation: Uses NETCONF to configure devices dynamically.

Huawei iMaster NCE-WAN: Automates device onboarding and template-based configurations.

✅ Reference: Huawei HCIE-Datacom Guide – NETCONF Protocol and Configuration Operations

Comprehensive and Detailed In-Depth Explanation:

Telemetry in a narrow sense refers specifically to the device-side telemetry process, which includes the following key modules:

Data generation (A): The device collects and generates telemetry data, such as performance metrics or operational statistics.

Data push (B): The device actively pushes the collected data to the configured destination (such as a collector or management system) using a data streaming protocol.

Data source (C): The entity on the device that generates or provides the monitored data.

Data subscription (D) is not part of the device-side telemetry; it is related to the management system side, where users subscribe to specific telemetry data streams.

Therefore, the correct answers are A, B, C.

Dynamic VLAN Authorization in Huawei CloudCampus

Dynamic VLAN assignment allows users to be placed into specific VLANs based on authentication methods, ensuring security and network segmentation.

Correct Explanations:

✅ A. Wired users using 802.1X authentication receive VLAN assignments dynamically.

After authentication, the access control system (e.g., iMaster NCE-Campus) assigns VLANs dynamically.

✅ C. Wireless users using 802.1X authentication also receive VLAN assignments.

Similar to wired users, wireless 802.1X authentication allows dynamic VLAN assignment via the RADIUS server.

✅ D. Wired users using MAC authentication can receive VLAN assignments.

If a user does not support 802.1X, MAC authentication can still be used to assign VLANs dynamically.

Incorrect Statement Explanation:

❌ B. When wireless users pass Portal authentication, they join the authorization VLANs delivered to edge nodes.

Wrong! In Portal authentication, VLAN assignment is not dynamically delivered because Portal authentication typically applies access policies, not VLAN changes.

Dynamic VLAN assignment is mainly used with 802.1X or MAC authentication.

Reference from Huawei HCIE-Datacom Documentation:

Huawei CloudCampus Configuration Guide – Dynamic VLAN Assignment and Authentication

HCIE-Datacom Training Material – VLAN Authorization in Virtualized Campus Networks