H12-821_V1.0 HCIP-Datacom-Core Technology V1.0 Questions and Answers

The security policy specifies that traffic originating from 12.1.1.2 and destined for the untrust zone is permitted. Since the source address of the packet (12.1.1.1) does not match this rule, the packet matches the default implicit deny rule. However, rule 1 does not deny all other traffic explicitly, so the packet is forwarded based on further configurations ​.

The Link State ID in a Type 3 LSA (Summary LSA) indicates the network or subnet being summarized, not the router ID of an ABR. All other statements accurately describe OSPF functionality, making D the false statement ​.

When routes are imported into BGP using the import-route command, the origin attribute is set to incomplete by default. This indicates that the route's origin is not known or is from an external source, as opposed to being explicitly learned through an IGP (IGP) or EGP (EGP) protocol ​.

Attributes such as community, tag, and origin can be directly referenced in the apply clause of a route-policy. However, IP-prefix is not an attribute but a prefix list used for matching, and it cannot be directly applied ​.

Comprehensive and Detailed Step-by-Step Explanation:

Default Next Hop Behavior in BGP:

Locally Originated Routes (A): The next hop is set to the advertising router's interface IP address.

Routes Received from EBGP (B): The next hop is not changed when these routes are advertised to IBGP peers. (This makes Option B false.)

Routes Advertised to EBGP (C): The next hop is set to the interface IP address of the advertising router.

Routes Advertised Between IBGP Peers (D): The next hop is not modified by default.

Incorrect Statement:

Option B is incorrect because the next hop of a non-labeled route received from an EBGP peer is not changed when it is advertised to IBGP peers.

References:

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

Huawei BGP Routing Principles

BFD control packets are encapsulated in UDP packets, and the destination port number for multi-hop BFD control packets is 4784. This is a standardized port for multi-hop BFD operation ​.

The Origin attribute in the display bgp routing-table output is marked as i, indicating that the route was injected into the BGP routing table using the network command. The other options are incorrect because the AS path is not displayed, the MED is 0, and the route is marked as the best (>), meaning it is the optimal route ​.

The information provided indicates that the configured query interval is 60 seconds, which applies to general queries. Group-specific queries are sent at a shorter interval, usually derived from the maximum response time. Therefore, the statement about a 60-second interval for group-specific queries is false. Other statements regarding maximum response time (10s), IP address, and IGMP version (V2) are correct ​.

OSPF (Open Shortest Path First) mandates that the backbone area (Area 0) serves as the central area for routing information exchange. To avoid inter-area routing loops, routing information is only exchanged between the backbone area and non-backbone areas, not directly between two non-backbone areas. Consequently, each Area Border Router (ABR) must connect to the backbone area to facilitate this routing exchange ​.

To compress the IPv6 address 2001:0DB8:0000:C030:0000:0000:09A0, the following rules are applied:

Remove leading zeros in each hextet (e.g., 0DB8 becomes DB8).

Replace contiguous blocks of zeros with :: (only once in the address).Thus, the compressed form is 2001:DB8:0:C030::9A0 ​.

When STP and RSTP coexist in a network, RSTP switches will downgrade their operation to STP to ensure compatibility. However, this disables RSTP's rapid convergence features, as the protocol behaves like STP to maintain interoperability ​.

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 asbr-summary command is executed in the global OSPF view to summarize external routes. The abr-summary command is executed in the OSPF area view to summarize routes between areas. By default, the advertise parameter is enabled unless explicitly overridden by the not-advertise option ​.

Option A correctly configures the DHCP relay agent (AC) to forward requests to the DHCP server using VLAN 10.Option B correctly configures the DHCP server (AR) with the correct IP pool (10.1.1.0/24), gateway, and excluded IP addresses. The static route to 10.1.1.0 through 172.21.1.1 ensures proper routing ​.

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Comprehensive and Detailed Step-by-Step Explanation:

1. Port Priority in RSTP:

RSTP (Rapid Spanning Tree Protocol) elects root and designated ports based on port priority and port ID.

Port priority is a configurable value that helps determine which port becomes the root or designated port when multiple ports are eligible.

The port ID consists of the port priority and port number. When priorities are equal, the port number is used as a tiebreaker.

2. Default Port Priority on Huawei Switches:

On Huawei switches, the default port priority is 128.

This value can be adjusted in increments of 16 using the command stp port priority.

3. Analysis of Options:

Option A: 1

Incorrect. This is not the default port priority value.

Option B: 128

Correct. This is the default port priority value on Huawei switches.

Option C: 4096

Incorrect. This is not a valid default port priority value.

Option D: 32768

Incorrect. This is the default bridge priority, not the port priority.

4. Summary:

The default port priority on Huawei switches is 128.

The hardware modules of Huawei modular devices and their functions are:

Main Processing Unit (MPU): Provides control and management planes for the entire system, responsible for protocol processing, system security, and software upgrades.

Switch Fabric Unit (SFU): Provides the data plane, enabling high-speed data switching between service modules.

Line Processing Unit (LPU): Manages data forwarding, offering various interfaces (optical and electrical) for data access​​.

Comprehensive and Detailed in-depth Step-by-Step Explanation:OSPF routers establish neighbor relationships and progress through various states during the adjacency formation process. The ExStart state is where routers negotiate the master and slave roles. This negotiation is critical because the master initiates the Data Description (DD) packet exchange process.

Here’s a breakdown of the relevant OSPF states:

ExStart State:

This is the phase where the routers determine which one will act as the master and which will be the slave.

The decision is based on the Router IDs of the two routers. The router with the higher Router ID becomes the master.

Exchange State:

After the master-slave roles are established, the routers exchange DD packets. These packets contain summaries of the LSAs in their respective LSDBs.

2-way State:

This state indicates that bidirectional communication has been established between the two routers, but it occurs before master-slave negotiation.

Init State:

This is an early state where a router has sent a Hello packet to its neighbor but has not yet received a Hello packet in response.

Key Point:The negotiation of master and slave roles happens exclusively in the ExStart state, making D. ExStart the correct answer.

References:

Huawei HCIA-Datacom Study Guide, Chapter on "OSPF Neighbor States".

RFC 2328 – OSPF Version 2 (Section 10.8).

 OSPF Area Design and Loop Prevention:OSPF uses a hierarchical structure with areas to improve scalability and efficiency. Area 0, the backbone area, plays a crucial role in ensuring loop-free route distribution between areas. The following mechanisms are key to preventing routing loops:

Strict adherence to hierarchical area design.

Prohibition of direct inter-area route exchanges between non-backbone areas.

The error indicates "Incorrect remote AS," which refers to a mismatch in the autonomous system (AS) numbers during BGP peer configuration. This issue is unrelated to the neighbor address. The neighbor address (10.1.1.5) and timestamp (2010-03-22 12:40:39) provided in the output are correct, and the error type confirms a neighbor relationship issue ​.

Access Control Lists (ACLs) can be classified into several types, including Basic ACL (filters based on source IP), Advanced ACL (filters based on multiple parameters like source and destination IP, protocol, and ports), and Layer 2 ACL (filters based on MAC addresses). User-defined ACLs are not a standard classification ​.

In asynchronous mode, two devices exchange BFD Control packets to monitor connectivity. However, this mode does support the echo function, which tests bidirectional paths by sending packets that loop back to the origin. This statement is incorrect. Demand mode, on the other hand, minimizes the control packet exchange, relying on periodic echo packets if configured. Huawei's BFD configuration guides emphasize these distinctions ​.

Intra-area route calculation in OSPF involves only Router LSAs (Type 1) and Network LSAs (Type 2). Summary LSAs (Type 3) are used for inter-area routes and do not participate in intra-area route calculation. Therefore, the statement is false ​.

 IS-IS Interface Types

IS-IS interfaces are categorized based on physical link characteristics:

Point-to-Point (P2P): Direct connections between two routers.

Broadcast: Shared medium networks where multiple routers communicate.

 Incorrect Options

C. P2MP and D. NBMA are not standard interface classifications in IS-IS.

 HCIP-Datacom-Core Reference

IS-IS physical link classifications are elaborated in IS-IS link configuration sections​​.

BGP does not advertise all routes learned from peers to other peers. By default, only the best (optimal) routes selected by BGP are advertised to other peers. Additionally, routes learned from IBGP peers are not forwarded to other IBGP peers unless a route reflector or confederation setup is used. The statement claiming all learned routes are advertised is false ​.

Comprehensive and Detailed in-depth Step-by-Step Explanation:In an Intermediate System to Intermediate System (IS-IS) network, a Designated Intermediate System (DIS) is elected on broadcast networks to perform the following functions:

Represent the broadcast network as a pseudonode.

Generate and update the Link State Protocol Data Units (LSPs) for the pseudonode.

The DIS is elected based on the DIS priority value, which is configured on IS-IS interfaces. If two routers have the same priority, the router with the higher MAC address becomes the DIS.

The default DIS priority for IS-IS interfaces is 64, which can be modified depending on the network requirements.

Option A (200): Incorrect. This is not the default value.

Option B (64): Correct. This is the default DIS priority value.

Option C (1): Incorrect. This is not the default value.

Option D (100): Incorrect. This is not the default value.

References:

Huawei HCIA-Datacom Study Guide, Chapter on "IS-IS Basics".

RFC 1195 – Use of OSI IS-IS for Routing in TCP/IP and Dual Environments.

The forwarding plane of a switch consists of data forwarding hardware, such as line cards or forwarding engines, and is responsible for tasks like encapsulating/decapsulating packets, providing high-speed data channels, and collecting packet statistics. However, main control boards are part of the control plane, not the forwarding plane. This distinction ensures a separation of data forwarding and control functionalities ​.

Comprehensive and Detailed Step-by-Step Explanation:

Session Creation in Firewalls:

Firewalls create session entries for packets requiring stateful inspection (e.g., TCP, UDP, ICMP, and GRE).

Subsequent fragments of large packets do not require new sessions. Instead, they are processed based on the session created for the first fragment.

Correct Option:

C (Subsequent Fragment): Does not trigger a new session entry as it belongs to an existing session.

References:

HCIA-Datacom Study Guide, Chapter: Firewall Session Handling

Huawei Fragmentation Processing in Firewalls

 LSA Lifetime and Deletion

The LS Age field in the LSA header tracks the age of an LSA. When the LS Age reaches its maximum value (3600 seconds), the LSA is marked for deletion. This ensures old or stale LSAs are removed from the network to maintain accurate routing information.

 HCIP-Datacom-Core Reference

Detailed explanation of LS Age behavior and LSA deletion processes can be found in the OSPF LSDB and LSA sections​​.

When the router ID is configured in both the system view and the BGP view, the router ID in the BGP view takes precedence because BGP-specific configurations override global settings. This ensures that BGP operates with the most relevant configurations ​.

OSPF supports both area-level and interface-level authentication. When both are configured, interface authentication takes precedence over area authentication. This hierarchy ensures that specific interface-level configurations override the broader area-level settings when applicable ​.

Comprehensive and Detailed Step-by-Step Explanation:

STP and RSTP Behavior:

STP: Only the designated port processes inferior BPDUs. Inferior BPDUs are received from downstream switches and typically indicate topology changes.

RSTP: All ports, regardless of role (root, designated, or alternate), process inferior BPDUs to ensure faster convergence.

Behavior Difference:

RSTP improves convergence by allowing any port to process inferior BPDUs, unlike STP, which restricts this function to designated ports.

References:

HCIA-Datacom Study Guide, Chapter: STP vs RSTP

Huawei STP and RSTP Configuration Comparison

Comprehensive and Detailed in-depth Step-by-Step Explanation:BGP (Border Gateway Protocol) uses specific message types to establish and maintain peer relationships between routers. The primary BGP messages involved during the establishment and maintenance of peer relationships are:

Open (D):

The Open message is the first message sent after a TCP connection is established between BGP peers.

It is used to exchange parameters such as the AS number, BGP version, hold time, and BGP identifier.

Keepalive (A):

After the Open message exchange, Keepalive messages are sent periodically to maintain the BGP session.

These messages confirm that the connection is still alive.

Update (C):

Update messages are used to exchange routing information after the peer relationship is established.

They contain information about network prefixes and their associated path attributes.

Hello (B):

Hello messages are not used in BGP. They are typically used in protocols like OSPF or IS-IS to establish and maintain neighbor relationships.

Thus, the correct answers are A (Keepalive), C (Update), and D (Open).

References:

Huawei HCIA-Datacom Study Guide, Chapter on "BGP Message Types".

RFC 4271 – Border Gateway Protocol 4 (BGP-4).

Comprehensive and Detailed Step-by-Step Explanation:

1. Understanding IGMP Version Compatibility:

IGMP (Internet Group Management Protocol) supports multiple versions, such as IGMPv1, IGMPv2, and IGMPv3.

A device running a later version of IGMP is backward-compatible and can identify Report messages from earlier versions.

However, a device running an earlier version of IGMP cannot recognize the newer features or formats of later IGMP versions.

2. Best Practice:

To avoid compatibility issues, the IGMP version configured on the switch should be the same as or later than the version used by the member hosts in the network.

3. Why the Statement is TRUE:

The statement is correct because it describes the compatibility behavior of IGMP versions and advises setting the switch IGMP version appropriately.

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:

iMaster NCE-Campus Overview:

iMaster NCE-Campus is Huawei’s network management platform for managing and controlling campus networks.

It supports user authentication, including STA (Station) authentication, in WLAN environments.

Authentication Modes Supported:

iMaster NCE-Campus integrates with AAA (RADIUS) servers to perform authentication for wireless clients.

Correct Statement:

The platform can function as an authentication server for WLAN STAs.

References:

HCIA-Datacom Study Guide, Chapter: WLAN Management with iMaster NCE-Campus

Huawei iMaster NCE-Campus Product Overview

In a stateful inspection firewall, if the status detection mechanism is enabled, it tracks and validates the state of connections using the session table. If there is no session table and a SYN+ACK packet reaches the firewall, it checks the security policy. If the policy explicitly permits the packet, it will pass through the firewall, but no session table will be created without the initial SYN packet. The other options are either incorrect or misrepresent the behavior of stateful inspection ​.

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 ​.

Comprehensive and Detailed Step-by-Step Explanation:

Multi-Channel Protocols:

Multi-channel protocols use separate channels for control and data communication, requiring application-specific packet filtering (ASPF) to track sessions.

Examples:

FTP (A): Uses separate control and data channels.

SIP (B): Uses multiple ports for signaling and media.

H.323 (D): A VoIP protocol using multiple channels.

Single-Channel Protocol:

SMTP (C): A single-channel protocol for email communication, which does not require ASPF.

References:

HCIA-Datacom Study Guide, Chapter: Firewall ASPF Configuration

Huawei Multi-Channel Protocol Handling

 ACL Modification

Named ACLs can be modified after their creation. Unlike numbered ACLs, named ACLs provide greater flexibility for editing individual rules without deleting the entire ACL.

Therefore, the statement is incorrect.

 HCIP-Datacom-Core Reference

The flexibility and editability of named ACLs are discussed in the ACL configuration sections​​.

 IP Prefix List Matching Conditions

An IP prefix list matches based on:

Mask: Specifies the subnet mask length.

Action: Specifies whether to permit or deny.

Index: Orders the rules within the prefix list.

Port numbers are not applicable as matching conditions in an IP prefix list.

 HCIP-Datacom-Core Reference

IP prefix list configurations are detailed in the routing policy and route filtering chapters​​.

BFD operates at the network layer, providing rapid fault detection for forwarding paths, such as IP routing and MPLS tunnels. It interacts closely with network protocols (e.g., OSPF, BGP) to ensure high reliability and quick response to faults. BFD does not belong to the application, data link, or physical layers but functions as a network layer diagnostic tool as confirmed in Huawei's network protocol training ​.

 BGP Open Message Components

The Open message contains the following critical parameters:

Local AS Number: The autonomous system of the router.

Router ID: A unique identifier for the router.

Hold Time: The maximum time the router will wait for Keepalive or other messages from its peer.

 Incorrect Option

C. NLRI: Network Layer Reachability Information is not included in Open messages; it is carried in Update messages.

 HCIP-Datacom-Core Reference

The structure and contents of Open messages are explained in BGP protocol details​​.

Comprehensive and Detailed in-depth Step-by-Step Explanation:To establish an OSPF neighbor relationship, the following conditions must be met:

The routers must share a common network segment.

Their Hello and Dead intervals must match.

Their OSPF network types must be compatible.

The IP subnet masks must match.

If two OSPF routers are on different network segments and have different subnet masks, one solution is to change the OSPF network type to Point-to-Point (P2P) on both interfaces.

Point-to-Point (P2P):

In a P2P network type, OSPF ignores the subnet mask mismatch and establishes the neighbor relationship regardless of the network mask.

This is ideal for directly connected links between two routers.

NBMA (Non-Broadcast Multi-Access):

This network type is used for networks like Frame Relay or ATM, where a single physical interface connects to multiple neighbors.

It is not applicable to solving subnet mask mismatches for a single link.

P2MP (Point-to-Multipoint):

This type treats the link as multiple P2P links. It is mainly used in hub-and-spoke topologies.

While it can be configured to solve subnet mask mismatches, it is more complex and less commonly used compared to the P2P type.

Broadcast:

This type requires all routers on the same segment to agree on subnet masks, so it cannot resolve the subnet mask mismatch issue.

Therefore, the correct answer is A. Point-to-point.

References:

Huawei HCIA-Datacom Study Guide, Chapter on "OSPF Neighbor Relationships".

RFC 2328 – OSPF Version 2, Section 10.

In a route-policy, attributes such as MED (Multi-Exit Discriminator) and Local-Preference can be used in apply clauses to influence BGP route selection. Attributes like AS_Path and Tag are typically matched or filtered but not directly applied in the apply clause ​.

Understanding DIS Election in IS-IS:

On an IS-IS broadcast network, a Designated Intermediate System (DIS) is elected to create and update pseudonodes for efficient communication.

The election is based on the following criteria:

DIS Priority: The router with the highest priority is elected as the DIS.

Router ID (tie-breaker): If priorities are equal, the router with the highest Router ID is elected.

Analyzing the DIS Priorities and Router IDs:

R1: Priority = 64, Router ID = 1.1.1.1

R2: Priority = 1, Router ID = 2.2.2.2

R3: Priority = 127, Router ID = 3.3.3.3

R4: Priority = 10, Router ID = 4.4.4.4

Among the routers, R3 has the highest DIS priority (127), making it the DIS.

Correct Option:

Option B (R3): Correct, as R3 has the highest priority.

Option A (R1): Incorrect, as its priority is lower (64).

Option C (R4): Incorrect, as its priority is lower (10).

Option D (R2): Incorrect, as its priority is the lowest (1).

References:

HCIA-Datacom Study Guide, Chapter: IS-IS DIS Election

Huawei IS-IS Configuration and DIS Role Details

Comprehensive and Detailed Step-by-Step Explanation:

1. Overview of PBR (Policy-Based Routing):

Policy-Based Routing (PBR) allows you to override traditional routing decisions by defining user-specific policies.

Interface-Based PBR: Applied to packets arriving at a specific interface and affects traffic being forwarded through the device.

Local PBR: Applied to traffic generated by the local router itself (e.g., locally originated packets such as management traffic).

2. Analysis of Each Statement:

Option A: Interface-based PBR takes effect only for forwarded packets.

Correct (True Statement).

Interface-based PBR applies only to packets arriving at a specific interface and being forwarded through the router. It does not affect locally originated traffic.

Option B: Local PBR takes effect only for locally originated packets.

Correct (True Statement).

Local PBR specifically applies to traffic generated by the router itself, such as pings, SNMP requests, or routing protocol updates.

Option C: Interface-based PBR is configured on an interface and takes effect only for incoming packets on the interface.

Correct (True Statement).

Interface-based PBR is applied directly on the interface using commands like policy-based-route. It only affects traffic entering the specified interface.

Option D: Local PBR is configured in the protocol view.

Incorrect (False Statement).

Local PBR is not configured in the protocol view. It is typically configured using the command local-policy in the system view to handle traffic generated by the router.

3. Summary:

Correct Answer: D (Local PBR is NOT configured in the protocol view).

When the level of an IS-IS interface is changed, the adjacency must be re-established because IS-IS adjacencies are formed based on matching levels (Level-1, Level-2, or both). Other changes, such as cost or hello intervals, do not disrupt the existing adjacency but might impact routing metrics or timing ​.

In asynchronous mode, the local device sends BFD control packets at predefined intervals, and the remote device monitors the receipt of these packets to detect connectivity issues. This is one of the two operating modes in BFD, the other being demand mode ​.

The default sending interval for BFD (Bidirectional Forwarding Detection) control packets is 100 milliseconds. This interval ensures rapid detection of link faults, providing fast failover and minimizing downtime in network operations ​.

Comprehensive and Detailed Step-by-Step Explanation:

1. Single-Hop BFD Session:

A single-hop BFD session is used to detect link failures between directly connected devices.

It is bound to the local IP address and the peer IP address, and the session relies on these parameters to establish connectivity.

2. Why Modifications Require Deletion:

BFD sessions are tightly bound to their configuration parameters (e.g., local and peer IP addresses).

Modifying these parameters is not supported for an existing session. Instead, you must delete the session and recreate it with the updated parameters.

3. Why the Statement is TRUE:

The statement correctly describes the behavior of BFD sessions, where modifying an existing session is not possible without deleting it first.

 GMP Snooping Proxy

IGMP snooping proxy allows the switch to substitute for upstream Layer 3 devices and downstream hosts, reducing unnecessary bandwidth consumption by consolidating IGMP messages.

 HCIP-Datacom-Core Reference

The IGMP snooping proxy functionality is described in multicast optimization and IGMP configuration chapters​​

 OSPF Authentication OverviewOSPF supports three authentication modes:

Null Authentication: No authentication (default).

Plaintext Authentication: Uses clear-text passwords.

MD5 Authentication: Secure cryptographic authentication.

 Interface-Level PriorityWhen both interface-level and area-level authentication are configured, OSPF prioritizes interface-level authentication. This ensures that interface-specific security overrides area-wide configurations for greater granularity and security.

 HCIP-Datacom-Core Reference

OSPF authentication hierarchy and configurations are detailed in the OSPF security configuration chapter​.

 ACL Matching in Huawei Routers:

Access Control Lists (ACLs) are used to filter packets based on specific criteria, such as source/destination IP, ports, or protocols.

When a packet arrives, the Huawei router processes it against the configured ACL rules to decide whether to permit or deny the packet.

IGMPv1 supports general queries but does not define a Leave message. IGMPv2 introduces the Leave message type, which allows hosts to notify routers when they wish to leave a multicast group, improving efficiency. These distinctions align with the functionality of IGMP versions ​.

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 ​.

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Explanation of IS-IS Packet Types and Synchronization Process:

In the given scenario, R2 requests LSPs from R1 to synchronize its Link State Database (LSDB). The following IS-IS packet types are involved in this synchronization process:

1. P2P IIH (Point-to-Point IS-IS Hello):

Purpose: Establishes and maintains IS-IS neighbor relationships.

Step: This packet is exchanged initially to detect and maintain the adjacency between R1 and R2.

2. PSNP (Partial Sequence Number PDU):

Purpose: Requests missing or outdated LSPs (Link State PDUs) from a neighbor to synchronize the LSDB.

Step: In this case, R2 sends a PSNP to R1 to request the missing or outdated LSP.

3. LSP (Link State PDU):

Purpose: Contains routing information and is used to update the LSDB.

Step: R1 sends the requested LSPs to R2 for synchronization.

4. CSNP (Complete Sequence Number PDU):

Purpose: Lists all LSPs in the sender's LSDB to help neighbors verify and request missing LSPs.

Step: R1 sends a CSNP during retransmission timeout to notify R2 of its LSPs.

IGMPv3 builds on IGMPv1 and IGMPv2 by supporting all previous query types, including General Query and Group-Specific Query, while introducing Source/Group-Specific Query. This enhancement allows finer control over multicast group membership ​.

Comprehensive and Detailed Step-by-Step Explanation:

1. Features of Wi-Fi 6:

Wi-Fi 6 (802.11ax) introduces several new technologies to improve network efficiency, reduce latency, and optimize power usage:

OFDMA (Orthogonal Frequency Division Multiple Access): Allows multiple devices to transmit simultaneously, improving concurrency.

TWT (Target Wake Time): Reduces power consumption by scheduling communication times for devices.

High Bandwidth: Supports up to 9.6 Gbps, significantly faster than Wi-Fi 5.

2. Why Zero Latency is Incorrect:

While Wi-Fi 6 reduces latency compared to earlier standards, zero latency is not achievable due to inherent delays in network communication.

The statement "Realizes zero latency" is misleading and technically inaccurate.

3. Analysis of Each Option:

Option A: Uses OFDMA technology to achieve high concurrency.

Correct (True Statement).

OFDMA is a core feature of Wi-Fi 6 that improves concurrent communication.

Option B: Realizes zero latency, ensuring efficient service running.

Incorrect (False Statement).

Wi-Fi 6 reduces latency but cannot eliminate it entirely.

Option C: Provides high bandwidth, up to 9.6 Gbps.

Correct (True Statement).

Wi-Fi 6 supports a theoretical maximum bandwidth of 9.6 Gbps.

Option D: Uses TWT technology to reduce terminal power consumption.

Correct (True Statement).

TWT schedules communication times, allowing devices to enter low-power states and conserve battery life.

4. Summary:

The false statement is B, as Wi-Fi 6 does not achieve zero latency.

AI-driven networks focus on maximizing efficiency by minimizing latency to enhance data processing and decision-making speed. The AI era emphasizes leveraging large data volumes and ensuring rapid data center interconnectivity. This makes low latency a critical requirement for AI-ready data center networks, as highlighted in Huawei's AI and data center network optimization materials ​.

A stateful inspection firewall tracks the state of network connections and only matches the initial packet against its rule set. Subsequent packets in the same connection are matched in the state table. Contrary to this, UDP packets can be inspected by correlating them with connection states, and packets in a single connection are always correlated ​.

Comprehensive and Detailed Step-by-Step Explanation:

VRRP Virtual MAC Address Format:

The VRRP virtual MAC address is generated using the format:0000-5e00-01XX, where XX represents the VRID in hexadecimal.

Calculation:

VRID = 1 → Hexadecimal = 01.

Virtual MAC = 0000-5e00-0101.

Correct Option:

C (0000-5e00-0101).

References:

HCIA-Datacom Study Guide, Chapter: VRRP MAC Address Format

Huawei VRRP Configuration Guidelines

Let me continue with the next set of questions!

Comprehensive and Detailed Step-by-Step Explanation:

1. What is the BFD Echo Function?

BFD (Bidirectional Forwarding Detection) is used to detect link failures.

The Echo function is an optional feature that tests link connectivity by looping back packets sent from the local device through the forwarding path.

2. Analysis of Each Statement:

Option A: If URPF is enabled on the peer end, BFD packets may be incorrectly discarded on the peer end.

Correct.

URPF (Unicast Reverse Path Forwarding) checks whether the source IP address of an incoming packet is reachable via the interface it was received on. Since the Echo function uses loopback packets, this can conflict with URPF, causing the packets to be dropped.

Option B: In the BFD Echo function, the device uses the IP address of the outbound interface as the source IP address by default.

Correct.

By default, the outbound interface's IP address is used as the source address for BFD Echo packets.

Option C: The BFD Echo function applies only to single-hop BFD sessions.

Incorrect.

The BFD Echo function can be used for both single-hop and multi-hop BFD sessions.

Option D: When configuring a BFD session supporting the BFD Echo function, you need to configure both the local and remote discriminators.

Incorrect.

The BFD Echo function is locally configured and does not require setting remote discriminators. The function operates independently of the remote device's configuration.

3. Summary:

The correct statements are A and B.

The Forwarding Information Base (FIB) is derived from the router's routing table and contains the exact forwarding entries used to route packets. It directly guides packet forwarding decisions by matching incoming packets with the correct output interface or next-hop address ​.

Comprehensive and Detailed Step-by-Step Explanation:

Packet Filtering Firewall:

A packet filtering firewall inspects packets at the network and transport layers based on predefined rules (e.g., ACLs).

Correct Statements:

Option B: Packet filtering is performed on a per-packet basis.

Option D: ACLs define the filtering rules for traffic.

Incorrect Statements:

Option A: Packet filtering firewalls do not analyze associated packets. For this, a stateful firewall is required.

Option C: Application-layer inspection is not supported. This functionality is provided by application-layer firewalls.

References:

HCIA-Datacom Study Guide, Chapter: Firewalls

Huawei Firewall Packet Filtering Configuration

Routing policies are used to control how routes are imported, advertised, or received. Policy-Based Routing (PBR) is used to forward packets based on policies, bypassing the routing table. Routing policies are not used for packet forwarding ​.

The provided BGP error display shows the error timestamp as 12:40:39 on March 22, 2010. The error message confirms a mismatch in the peer AS number, as indicated in the "Incorrect remote AS" error info. This eliminates options related to other causes, and the timestamp in Option A is incorrect ​.

Comprehensive and Detailed in-depth Step-by-Step Explanation:To answer this question, it is essential to distinguish between the roles of ABRs and ASBRs in OSPF and the function of route summarization:

Route Summarization on ABRs:

Route summarization in OSPF can reduce the number of inter-area Type 3 LSAs that ABRs propagate between areas.

ABRs perform route summarization to reduce the amount of routing information exchanged between areas, thereby decreasing the size of the routing table and improving resource utilization.

Route Summarization on ASBRs:

ASBRs summarize external routes (from outside OSPF) into Type 5 LSAs or Type 7 LSAs (in NSSAs).

ASBR route summarization does not impact inter-area Type 3 LSAs because ASBRs are responsible for importing and summarizing external routes, not summarizing routes between OSPF areas.

Since the statement refers to configuring route summarization on ASBRs to reduce inter-area Type 3 LSAs, it is incorrect. Route summarization for inter-area Type 3 LSAs must be configured on ABRs, not ASBRs.

Correct Statement: Route summarization on ABRs reduces the number of inter-area Type 3 LSAs.

References:

Huawei HCIA-Datacom Study Guide, Chapter on "OSPF Route Summarization".

RFC 2328 – OSPF Version 2.

By default, Huawei firewalls create security zones named untrust, dmz, trust, and local. These zones facilitate security policies for inbound, outbound, and inter-zone traffic control ​.

Comprehensive and Detailed Step-by-Step Explanation:

Bidirectional Forwarding Detection (BFD):

BFD is a lightweight protocol that provides rapid fault detection on links independent of the underlying routing protocol or media.

Requirements for BFD:

Both devices at the endpoints of the link must support and configure BFD for it to operate.

If one device does not support BFD, the feature cannot be used for link detection.

References:

HCIA-Datacom Study Guide, Chapter: BFD Overview

Huawei BFD Configuration Guidelines

By default, BGP does not automatically summarize imported routes. Route summarization must be explicitly configured using the summary or similar commands ​.

The filter-policy command in IS-IS is used to control the advertisement and filtering of routing information. However, it does not directly filter LSPs (Link State Packets); instead, it controls route advertisements. The false statement here is that it filters LSPs ​.

Understanding the Network Setup:

The OSPF network consists of three areas (Area 1, Area 0, and Area 2).

The server's subnet 192.168.1.0/24 is directly connected to R1 and imported into OSPF using the command:

import-route direct type 1 cost 2

The type 1 specifies the route as an OSPF Type 1 external route, meaning both the external cost and the internal OSPF cost will be included when calculating the total cost.

The external cost specified for the imported route is 2.

Cost Calculation to R2:

The interfaces between the routers are GE interfaces, and the default cost for GE interfaces is 1.

The path from R2 to the server goes through the following hops:

R2 → R1: Cost = 1 (intra-area link).

R1 → Server: External cost = 2 (specified in the import-route command).

Total cost to R2:

Intra-area cost (1) + External cost (2) = 3

Verification of Each Option:

Option A (2): Incorrect. This only accounts for the external cost, ignoring the internal OSPF cost.

Option B (4): Incorrect. This overestimates the cost by adding an extra hop.

Option C (3): Correct. The total cost is 3 (1 for the intra-area link + 2 for the external cost).

Option D (1): Incorrect. This ignores the external cost of the imported route.

References:

HCIA-Datacom Study Guide, Chapter: OSPF Route Types and Cost Calculation

Huawei OSPF Cost Configuration Details

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 ​.

Comprehensive and Detailed Step-by-Step Explanation:

1. Overview of IP Multicast:

IP multicast is a method of delivering data from one source to multiple destinations simultaneously.

Unlike unicast (one-to-one communication) or broadcast (one-to-all communication), multicast is one-to-many, allowing data to be sent only to subscribers (multicast group members).

This significantly conserves bandwidth and reduces the load on the network because the source only sends a single stream of data, which is replicated by multicast routers as needed.

2. Use Cases for IP Multicast:

IP multicast is widely used in network services that involve real-time or large-scale data delivery, such as:

IPTV (Internet Protocol Television): Broadcasting live TV streams.

Real-Time Data Transmission: Delivering stock market data, sensor updates, etc.

Multimedia Conferencing: Supporting group calls, webinars, and online meetings.

3. Why the Statement is TRUE:

IP multicast reduces unnecessary traffic and maximizes efficiency, making it ideal for these types of network services.

 Neighbor Discovery Protocol (NDP):

NDP is a key protocol in the IPv6 protocol suite, replacing ARP (Address Resolution Protocol) in IPv4.

It operates using ICMPv6 (Internet Control Message Protocol for IPv6) and is critical for managing interactions between IPv6 nodes on the same link.

Comprehensive and Detailed Step-by-Step Explanation:

1. What is NETCONF?

NETCONF (Network Configuration Protocol) is an XML-based protocol used for network device configuration and management.

It enables reading, modifying, deleting, and restoring configurations programmatically.

2. Supported Operations:

Option A: Modifying configurations

Correct.

NETCONF allows you to modify existing configurations on network devices.

Option B: Deleting configurations

Correct.

Configurations can be deleted using NETCONF operations.

Option C: Restoring configurations

Correct.

NETCONF can restore configurations by applying previously saved configuration data.

Option D: Backing up configurations

Correct.

NETCONF can retrieve and save the current configuration as a backup.

3. Summary:

NETCONF supports all listed operations: modifying, deleting, restoring, and backing up configurations.