Free Practice Questions for Huawei H12-821_V1.0 Exam

Comprehensive and Detailed Step-by-Step Explanation:

1. Multicast Applications:

Multicast is ideal for applications where data is sent from one source to multiple receivers, such as:

Real-Time Audio Conferencing: Multicast delivers audio streams to participants without duplicating the same data for each receiver.

Livestreaming: Streaming live events to viewers using multicast minimizes bandwidth usage by delivering a single stream to multiple users.

Network TV: Multicast is used in IPTV to broadcast TV channels efficiently.

2. Why Data Warehouse is Incorrect:

Data warehouse does not involve point-to-multipoint transmission. Data warehouse activities (e.g., analytics or database queries) typically use unicast connections for communication between the server and the client.

3. Summary:

The correct options are A, B, C , as they all involve point-to-multipoint communication supported by multicast.

Comprehensive and Detailed Step-by-Step Explanation:

Default OSPF Hello Timer:

The OSPF Hello timer is used to send periodic Hello packets and maintain neighbor relationships.

Default Hello timers:

Broadcast and P2P: 10 seconds

NBMA and P2MP: 30 seconds

Network Types Using 30s Hello Time:

P2MP (C): OSPF sends Hello packets every 30 seconds by default.

NBMA (D): OSPF also uses 30 seconds for NBMA networks.

Secure access channels include protocols that encrypt the transmitted data to protect against interception or unauthorized access. HTTPS (HyperText Transfer Protocol Secure) ensures data encryption over web communications, while SFTP (Secure File Transfer Protocol) provides secure file transfer by utilizing SSH for data encryption. Telnet and SNMPv2, on the other hand, lack robust encryption and are considered insecure. Huawei security standards highlight the importance of encrypted communication to prevent data leaks ​.

Comprehensive and Detailed Step-by-Step Explanation:

IS-IS Three-Way Handshake:

IS-IS uses a three-way handshake to establish neighbor relationships.

This process is applied on both point-to-point (P2P) and broadcast network types to confirm bidirectional communication.

P2P Networks:

Routers directly exchange IS-IS Hello (IIH) packets to establish adjacency.

Broadcast Networks:

IS-IS also uses the three-way handshake on broadcast networks to ensure that the Designated Intermediate System (DIS) election and adjacency formation are correct.

Comprehensive and Detailed Step-by-Step Explanation:

IPv4 Address Classes:

Class D: Reserved for multicast and defined by the first four bits as 1110 .

Address range: 224.0.0.0 to 239.255.255.255.

Structure:

Class D does not include a network/host division, as it is designed for group communication rather than device identification.

Comprehensive and Detailed Step-by-Step Explanation:

1. What is VRF (Virtual Routing and Forwarding)?

VRF is a network virtualization technology that enables multiple isolated routing tables to coexist on a single physical device.

Each VRF instance is independent, which ensures separation between different VPNs or users.

2. Resources That VRF Can Independently Own:

Option A: Interface

Correct.

Each VRF instance can have its own set of interfaces. These interfaces are bound to a specific VRF, isolating traffic at the physical or logical port level.

Option B: Routing table

Correct.

VRF instances maintain independent routing tables. This ensures that routes for one VPN do not overlap or interfere with routes of another VPN.

Option C: MAC address table

Incorrect.

The MAC address table is part of Layer 2 operations and is shared by all VRF instances on the device. VRF operates at Layer 3 and does not isolate MAC address tables.

Option D: Routing protocol process

Correct.

Each VRF instance can run its own routing protocol processes (e.g., OSPF, BGP), and these processes are completely independent of other VRF instances.

3. Summary:

The correct resources that can be independently owned by a VRF instance are Interface , Routing Table , and Routing Protocol Process .

BGP routes have a variety of path attributes that describe their characteristics and influence route selection. These attributes include well-known mandatory attributes like AS-PATH and NEXT-HOP, as well as optional attributes like MED and LOCAL_PREF.

In Huawei devices, there is a Huawei-specific attribute called " preference " , which is a local parameter used to influence BGP route selection on the device.

Key Characteristics of " preference " :

It is valid only locally on the router.

It is not shared with BGP peers.

It helps the router determine the best route when multiple routes exist for the same prefix.

It appears in the BGP routing table output in lowercase as preference.

Thus, the correct answer is preference (entered in lowercase as required).

Goal Analysis:

Requirement:

The route to 192.168.3.0/24 must exist in R1 ' s and R3 ' s routing tables.

The route must not exist in R2 ' s routing table.

This requires filtering to ensure the route is either:

Blocked on R2 ' s routing table (via filtering on R2), or

Blocked before it is advertised to R2.

Analysis of Each Option:

Option A (Filter-policy on R2 for filtering received routes):

Applying a filter-policy on R2 to filter received routes will block the route from entering R2 ' s routing table but still allow it to propagate to R3.

This meets the requirement.

Option B (Filter-policy on R2 for filtering the routes to be advertised):

Blocking the advertisement of routes from R2 to other routers does not affect the routes received by R2 itself.

This does not meet the requirement but does not affect the propagation to R3.

This is valid if the received route is blocked.

Option C (Filter-policy on R1 for filtering the routes to be imported):

If the route is filtered on R1 during the import phase, the route will not exist in R1’s routing table and thus cannot be advertised to either R2 or R3.

This fails to meet the requirement because the route must exist in R1 ' s and R3 ' s routing tables.

Option D (Filter-policy on R1 for filtering the imported routes to be advertised):

Filtering routes on R1 before advertising to R2 will prevent R2 from receiving the route but allow R1 to advertise the route to R3.

This meets the requirement.

Correct Option:

C (Filter-policy on R1 for filtering the routes to be imported): This will prevent the route from existing in both R1 and R3, violating the stated requirement.