Passed Exam Today H12-891_V1.0

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.

VRRP (Virtual Router Redundancy Protocol) and Flapping

VRRP ensures gateway redundancy by allowing multiple routers to work together as a virtual router. Flapping occurs when the master and backup routers frequently switch roles.

Causes of VRRP Flapping:

✅ A. Too small interval between Advertisement packet transmissions – Can cause flapping

If the Advertisement interval is too short, frequent VRRP state changes can occur.

✅ C. Packet loss on an interface of the backup device – Can cause flapping

If the backup router loses VRRP packets, it might assume the master is down and initiate an election.

✅ D. Flapping on the link transmitting VRRP Advertisement packets – Can cause flapping

If the link used for VRRP experiences instability, packets may be lost, triggering VRRP role changes.

Incorrect Answer Explanation:

❌ B. Inconsistent preemption delay settings – Does NOT cause VRRP flapping

Preemption delay only affects when a router takes over as master after recovering from a failure.

It does not directly cause flapping because the role change happens only after a delay, preventing frequent transitions.

Reference from Huawei HCIE-Datacom Documentation:

Huawei VRRP Configuration Guide – Preventing VRRP Flapping

HCIE-Datacom Study Material – VRRP Timers and Stability

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

Comprehensive and Detailed In-Depth Explanation:

In the Huawei iMaster NCE-Campus solution, when using a third-party Portal authentication application, the following process occurs:

After the Wi-Fi user connects to the network, any attempt to access a website for the first time triggers HTTP redirection.

The user is redirected to the login page provided by the third-party authentication application.

This mechanism ensures that the user authenticates before accessing external resources.

The redirection behavior is consistent with captive portal functionality, which is standard for user authentication on Wi-Fi networks.

Therefore, the statement is TRUE.