Free Practice Questions for Huawei H12-891_V1.0 Exam

Huawei Open Programmability System (OPS) and HTTP Request Headers

Huawei OPS allows network automation and programmability through HTTP-based APIs. When using Python scripts to send HTTP requests to network devices, the request headers must specify the content format for data exchange.

✅ B. Content-Type: text/json, Accept: text/json (Correct Answer)

Content-Type: text/json → Specifies that the request body contains JSON-formatted data.

Accept: text/json → Specifies that the response should be in JSON format.

In OSPFv3, each LSA type has a defined flooding scope:

Link-LSA (Type 8)

Advertised only on the local link

Contains router’s link-local address and prefixes

Scope: Within the local link scope ✅

AS-External-LSA (Type 5)

Used to advertise external routes from outside the AS

Flooded across the entire autonomous system, except stub/NSSA areas

Scope: Within an AS ✅

Network-LSA (Type 2)

Generated by the Designated Router (DR)

Describes all routers on a broadcast or NBMA segment

Flooded within the originating area

Scope: Within an area ✅

Correct Mappings:

Link LSA → Within the local link scope

AS-External-LSA → Within an AS

Network-LSA → Within an area

OSPFv3 (for IPv6) introduces significant changes compared to OSPFv2 (for IPv4).

While both versions share similar routing mechanisms, there are key LSA format and functional differences beyond just address changes.

Major Differences Between OSPFv2 and OSPFv3:

Address Independence (LSA Format Changes)

OSPFv3 LSAs do not contain IP addresses directly; they rely on Link-LSA and Intra-Area Prefix LSA to advertise addresses.

In OSPFv2, IP addresses were included in LSA headers.

New LSA Types in OSPFv3

LSA Type 8 (Link-LSA): Advertises a router’s IPv6 address to neighbors.

LSA Type 9 (Intra-Area Prefix LSA): Replaces the address information in Router-LSAs and Network-LSAs.

Support for Multiple Address Families (AF)

OSPFv3 can support both IPv4 and IPv6 in newer implementations (RFC 5838).

Authentication Mechanism Removed

OSPFv3 relies on IPsec for authentication, whereas OSPFv2 had built-in authentication mechanisms.

Incorrect Statement Explanation:

❌ The statement " LSA formats and functions remain unchanged " is false because:

LSA structures were modified in OSPFv3.

New LSA types were introduced to handle IPv6 addresses separately.

Reference from Huawei HCIE-Datacom Documentation:

Huawei OSPFv3 Configuration Guide – LSA Differences from OSPFv2

HCIE-Datacom Study Material – OSPFv3 Evolution & IPv6 Implementation

Comprehensive and Detailed In-Depth Explanation:

By default, OSPF does not automatically associate a domain ID with a process ID. The concept of " domain ID " is primarily used when redistributing routes between OSPF and BGP, particularly in MPLS VPN scenarios. The domain ID in OSPF helps maintain loop prevention and correct route advertisement between different OSPF domains. You can manually configure the domain ID using the domain-id command within the OSPF process view, but it is not inherently set to the process ID.

The provided Python code uses the requests.post() function to make an HTTP POST request to retrieve a token from iMaster NCE. The body is structured using the json={} parameter, which serializes the dictionary into JSON format. The proper content-type and accept headers are included.

Let ' s analyze each option:

✅ Option A is correct: The print(r.json()) is a valid method to display JSON response from the server.

✅ Option B is correct: The token URL is constructed correctly: https://139.9.213.72:18002/controller/v2/tokens.

✅ Option C is correct: The request body is clearly in JSON format, specified by the json={...} argument.

❌ Option D is incorrect: The HTTP method used is POST, not GET. The statement is false, making it the correct answer to select.

Huawei Official Documentation Reference:

“To obtain a token, the client sends a POST request to /controller/v2/tokens, including credentials in the request body in JSON format.”

(Source: Huawei iMaster NCE RESTful API Reference Guide – Authentication Section)

Comprehensive and Detailed In-Depth Explanation:

In the Label Distribution Protocol (LDP) session establishment process, the Initialization message is sent by the initiator to propose parameters for the session. If the responder finds that the proposed parameters are not acceptable, it responds with an Error Notification Message. This message indicates that the session could not be established due to incompatible or incorrect parameters.

The Error Notification Message typically includes details about why the session could not be established, such as parameter mismatch or unsupported features. If the parameters are acceptable, the responder would instead reply with a Keepalive Message to maintain the session.

Comprehensive and Detailed In-Depth Explanation:

The Huawei SD-WAN Solution uses HTTP/2 as the primary protocol to report device performance data to the controller.

HTTP/2 is chosen for its high efficiency, low latency, and enhanced data transfer speed.

It supports bidirectional communication between devices and the iMaster NCE-Campus controller.

While protocols like NetFlow and SNMP are traditionally used for monitoring, Huawei SD-WAN specifically uses HTTP/2 for real-time performance reporting and control due to its modern web-based architecture.

In Huawei ' s SD-WAN architecture, the following channels are defined:

Management Channel (Callout 1)

Between iMaster NCE and Edge devices.

Used for device registration, configuration, and monitoring.

Encrypted with HTTPS.

Control Channel (Callout 2)

Between Edge devices and RR (Route Reflector).

Used for route exchange and control signaling, typically over MPLS or Internet.

Data Channel (Callout 3)

Between Edge to Edge (e.g., HQ to branch).

Used for actual service traffic transmission, carried over MPLS, Internet, or both.

Correct Mapping:

Management channel → Callout 1 (from iMaster NCE to Edge)

Control channel → Callout 2 (Edge to RR)

Data channel → Callout 3 (Edge to Edge, over MPLS/Internet)

A. The device sends sampled data every second → Correct, since sample interval is 1000ms = 1 second.

B. The subscription mode is static subscription → Correct, as shown by Sub state: PASSIVE. Passive indicates a static subscription.

C. The IP address of the device is 192.168.56.1 → Incorrect — this IP address is the destination (telemetry collector), not the device’s own IP.

D. The subscription name is Sub1 → Correct, as per Sub name : Sub1.

Correct answer: C. The IP address of the device is 192.168.56.1 — this is incorrect because it ' s actually the collector’s IP, not the device ' s.

In hot standby (active-active/load balancing) scenarios, Quick Session Backup is critical. This function ensures that session entries are immediately synchronized between firewalls to handle asymmetric traffic (where return traffic goes through a different firewall than the forward traffic).

Without it, the return packet may be dropped due to missing session information on the alternate firewall.

Exact Extract - HCIE-Datacom Security Module:

“When VGMP is in load balancing mode, quick session backup must be enabled to prevent traffic loss due to inconsistent forward and return paths.”