H12-821_V1.0 Exam Dumps - Huawei HCIP-Datacom Questions and Answers

When configuring VRRP, the virtual router priority and virtual IP address are mandatory because they define the VRRP instance and its role within the group. Preemption mode and preemption delay are optional configurations that influence how routers take over the master role when priorities change. These are not mandatory for the VRRP protocol to function ​.

Comprehensive and Detailed Step-by-Step Explanation:

Analysis of VRRP Configuration:

Option A (Preemption): Correct. The output explicitly states that preemption is enabled.

Option C (Authentication): Correct. Authentication is enabled using MD5.

Option D (Group ID): Correct. The VRRP group ID is explicitly stated as 1.

False Statement:

Option B (mVRRP Group): The output does not indicate this is an mVRRP (Multicast VRRP) group. This feature must be explicitly configured and is not enabled by default.

References:

HCIA-Datacom Study Guide, Chapter: VRRP Configuration Details

Huawei VRRP Command Reference

Comprehensive and Detailed Step-by-Step Explanation:

Routing Table Structure:

Routers maintain a local core routing table and separate protocol routing tables for OSPF, BGP, etc.

The local core routing table stores optimal routes selected based on metrics, protocol preferences, and administrative distances.

Fields in the Core Routing Table:

Destination Address (A): Indicates the destination network or host.

Routing Protocol Preference (B): Determines the priority of routing protocols (e.g., OSPF > RIP).

Routing Protocol (D): Specifies the protocol (e.g., OSPF, BGP) that contributed the route.

Inbound Interface: This is stored in the protocol-specific routing table but not in the local core table.

References:

HCIA-Datacom Study Guide, Chapter: Routing Table Management

Huawei Routing Fundamentals

Comprehensive and Detailed Step-by-Step Explanation:

Single-Hop BFD:

Single-hop BFD is used for detecting link failures in directly connected devices.

It uses UDP port 3784 for communication.

Multi-Hop BFD:

For multi-hop scenarios, BFD uses UDP port 4784 to ensure end-to-end connectivity.

Incorrect Options:

TCP ports 3784 and 4784 (C and D): BFD does not use TCP.

References:

HCIA-Datacom Study Guide, Chapter: BFD Ports and Functions

Huawei BFD Configuration Details

In inter-AC roaming scenarios, an AC (Access Controller) can serve as the mobility server for multiple mobility groups, enabling it to manage roaming among multiple groups. However, an AC can only belong to one specific mobility group. This constraint ensures that mobility management remains streamlined and avoids conflicts. Huawei WLAN mobility configuration guides validate this setup ​.

The Originator ID in a BGP route represents the Router ID of the device that originally advertised the route into the BGP domain. Since RTA originates the route 10.1.1.0/24 into the BGP process, the Originator ID in the route received by RTD will be set to 1.1.1.1 ​.

Multi-channel protocols such as H.323 and FTP use separate control and data channels. H.323 uses different channels for call signaling and media streaming, while FTP uses a control channel for commands and a data channel for file transfers. Telnet and SMTP are single-channel protocols ​.

A screenshot of a computer Description automatically generated

Explanation of Root Port Election in STP:

In a Spanning Tree Protocol (STP) network, the Root Port is selected on each switch (except the Root Bridge). The Root Port is the port with the lowest path cost to the Root Bridge. If there is a tie in path cost, the following criteria are used in sequence to break the tie:

Steps for Root Port Election in Sequence:

RPC Comparison (Root Path Cost):

The port with the lowest Root Path Cost is preferred.

Root Path Cost is the cumulative cost of the path to the Root Bridge.

Peer BID (Bridge ID) Comparison:

If the Root Path Costs are equal, the Bridge ID of the connected switch (peer) is compared.

The port connecting to the switch with the lower Bridge ID is preferred.

Peer PID (Port ID) Comparison:

If the Bridge IDs are equal, the Port ID of the peer's sending port is compared.

The port connecting to the lower Port ID is preferred.

Local PID (Port ID) Comparison:

If all else is equal, the Local Port ID of the switch is used.

The port with the lower Local Port ID is selected.

A stateful inspection firewall tracks the state of active connections. If a packet matches an existing session in the firewall's state table, it is allowed to pass. The diagram indicates that the TCP packet matches the session state, so the firewall forwards it ​.