Free Huawei HCIP-Datacom-Core Technology V1.0 H12-821_V1.0 Exam Questions

Comprehensive and Detailed Step-by-Step

Blackhole Route Issue in BGP:

In IBGP, the next hop of a route learned from an EBGP peer is not changed by default. If an IBGP peer cannot reach the next hop, blackhole routes may occur.

To prevent this, the peer next-hop-local command is used to set the next hop to the local router's IP address.

Other Commands:

peer mpls-local-ifnet: Used in MPLS networks to set the next hop as the local interface address.

peer private-nexthop: Allows advertising private IP addresses as the next hop.

peer next-hop-invariable: Ensures the next hop is not modified during route advertisement, which is the opposite of what is required here.

HCIA-Datacom Study Guide, Chapter: BGP Next Hop Behavior

Huawei BGP Configuration Commands

In Huawei firewalls, the security level of a zone can be reconfigured by an administrator, making the statement that it cannot be changed false. Other statements accurately describe security level restrictions or defaults .

Edge ports are used in RSTP to bypass the spanning tree calculation for ports connected to end devices. By configuring ports like SWD's GE0/0/2 and SWC's GE0/0/2 as edge ports, they transition directly to the Forwarding state upon activation, ensuring faster convergence. Statement A is incorrect because receiving BPDU invalidates the edge port status .

ARP spoofing is a Layer 2 attack, as it targets ARP tables in switches or end devices. All other attacks, including IP spoofing, ICMP attacks, and Smurf attacks, are network layer (Layer 3) attacks .

The output shows that the router with the IP 10.0.12.2 is the Backup Designated Router (BDR), as indicated in the State: BDR field. The router ID is 10.0.2.2, the interface cost is 1, and the IP address of the interface is 10.0.12.2. Hence, C is the correct answer .

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IGMPv1 Querier Selection:

In IGMPv1, there is no built-in querier election mechanism. Querier selection depends on the multicast routing protocol (e.g., PIM).

IGMPv2 and IGMPv3 Querier Selection:

In IGMPv2 and IGMPv3, the router interface with the largest IP address in the multicast group is selected as the querier.

Correct Statement:

The statement accurately describes the querier selection mechanisms in IGMP versions.

HCIA-Datacom Study Guide, Chapter: IGMP Querier Mechanism

Huawei Multicast Protocol Comparison

The prefix list permits the prefix 1.1.1.1/24 with a mask length greater than or equal to /26 and less than or equal to /32. This means only prefixes with the base 1.1.1.1 and mask lengths between /26 and /32 will be permitted. Routes like 1.1.1.2/16 and 1.1.1.1/24 do not meet the mask length criteria, so they will be denied. Conversely, routes like 1.1.1.1/26 and 1.1.1.1/32 satisfy the condition and will be permitted .

Mandatory BGP Attributes

Next_Hop: Specifies the next hop to reach the destination.

AS_Path: Lists the autonomous systems traversed, crucial for loop prevention and route selection.

Optional Attributes

MED (Multi-Exit Discriminator) and Local_Preference are optional attributes that aid in route preference but are not mandatory.

HCIP-Datacom-Core Reference

BGP attribute behavior and classifications are detailed in BGP path selection principles.

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 .

Comprehensive and Detailed Step-by-Step

Overview of IGMP Versions:

IGMPv1: The simplest version, supports basic group membership management using Report messages but lacks Leave messages.

IGMPv2: Adds features like Leave messages and Group-Specific Queries.

IGMPv3: Supports specifying multicast sources for Source-Specific Multicast (SSM).

Feature Supported by All Versions:

Report messages are fundamental to IGMP functionality and are supported in all three versions.

Features Not Supported by All Versions:

Group-Specific Queries (A): Supported in IGMPv2 and IGMPv3.

Leave Messages (B): Introduced in IGMPv2.

Specifying Multicast Sources (D): Introduced in IGMPv3.

HCIA-Datacom Study Guide, Chapter: IGMP Overview

Huawei Multicast Protocol Details

Comprehensive and Detailed Step-by-Step

Analysis of the OSPF Neighbor State:

Router ID 10.0.5.5:

On interface 10.0.235.2 (GigabitEthernet0/0/1), the neighbor state is Full, indicating that adjacency is established.

The Designated Router (DR) is 10.0.235.5, which is the same as the neighbor's address.

Router ID 10.0.4.4:

On interface 10.0.24.2 (Serial1/0/1), the neighbor state is also Full, meaning adjacency is established.

The DR/BDR election status shows None, indicating that the interface is on a point-to-point link where DR/BDR election does not apply.

Validation of Each Option:

Option A: Correct. The DR IP address is explicitly shown as 10.0.235.5.

Option B: Correct. The neighbor state for both 10.0.5.5 and 10.0.4.4 is Full, confirming adjacency is established.

Option C: Incorrect. DR/BDR elections are irrelevant on point-to-point links like Serial1/0/1.

Option D: Correct. The Router IDs of R2's neighbors are explicitly listed as 10.0.5.5 and 10.0.4.4.

HCIA-Datacom Study Guide, Chapter: OSPF Neighbor Relationships

Huawei OSPF Neighbor and Adjacency Details

Comprehensive and Detailed Step-by-Step

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.

HCIA-Datacom Study Guide, Chapter: IPv4 Address Classes

Huawei Multicast Configuration Guidelines

Let me continue with the next set of questions!

Router LSAs (Type 1) and Network LSAs (Type 2) are advertised only within a single OSPF area, as they describe the topology within the area. In contrast, Summary LSAs (Type 3) and AS External LSAs (Type 5) are used for inter-area and external routing, respectively .

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BGP Origin Attribute Priority:

The Origin attribute determines the source of the route and affects the selection of the best path.

The priority order is as follows:

IGP (i): Highest priority. Routes injected using the network command.

EGP (e): Lower priority. Routes learned from the EGP protocol.

Incomplete (?): Lowest priority. Routes redistributed into BGP from other protocols.

Correct Option:

A: IGP > EGP > Incomplete is the correct order of priority.

HCIA-Datacom Study Guide, Chapter: BGP Path Selection

Huawei BGP Routing Rules

When a stack splits, the MAC addresses of the newly formed stacks do not change immediately. Instead, they retain their original MAC addresses until new ones are reassigned during topology updates. This delayed update prevents immediate conflicts and allows MAD (Multiple Active Detection) to handle any resulting issues .