Huawei H12-811_V1.0 HCIA-Datacom V1.0 Exam Exam Practice Test

Detailed Explanation:OSPF (Open Shortest Path First) uses protocol number 89 at the network layer. This distinguishes OSPF packets from other protocols such as TCP (protocol number 6) and ICMP (protocol number 1) .

Detailed Explanation:In a Layer 2 WLAN, an Access Controller (AC) typically handles authentication and management but does not act as a gateway. Instead, a Layer 3 device, such as a router, serves as the gateway. (Reference: HCIA-WLAN Training Material, WLAN Layer 2 and Layer 3 Concepts)

Statement A (False): Any router can function as an ASBR, not just ABRs. An ASBR is any router that connects OSPF to an external network, regardless of area.

Statement B (True): Area 0 is the OSPF backbone area, and all other areas must connect to it.

Statement C (True): Area partitioning reduces LSDB size by limiting the scope of LSAs within an area.

Statement D (True): Routers in the same area have the same LSDB, ensuring consistency in link-state information.

Thus, the correct answer is A (False statement).

Detailed Explanation:If the username does not contain the delimiter "@" followed by a domain name, the user is automatically assigned to the default domain. In this case, since the username "huawei" does not specify a domain, the user belongs to the default domain​​.

The command defines a static route to the network 10.0.12.0 with a 255.255.255.0 subnet mask, using 192.168.1.1 as the next-hop address. Static routes are manually set routes with fixed paths, and by default, they have higher priority than dynamic routes, but the specific preference value depends on configuration. This setup enables targeted routing for traffic towards the specified destination​.

The root path cost is calculated by summing the costs of each port on the path from the root bridge to the receiving port. In this case, assuming each link has a cost of 200, the total cost to reach the root from the indicated port would be 600, reflecting three hops from the root bridge​.

Router Initialization:

When a router boots up, it attempts to load its configuration file from the default save directory to initialize.

If the configuration file is missing, the router defaults to preconfigured parameters to ensure basic functionality.

Default Parameters:

These parameters include IP routing, interface defaults, and system-level settings. They allow network administrators to connect and manually configure the router.

Why Other Options Are Incorrect:

B: The "initial configuration file" refers to the manually created file, which may not exist.

C: The "current configuration file" is used during runtime but does not persist through reboots if unsaved.

D: A "new configuration file" must be manually created and does not exist by default.

References: HCIA-Datacom V1.0 Certification Guide, Chapter 2: Device Initialization.

STP Forwarding State:In the forwarding state, a port can:

Send and receive BPDUs (Bridge Protocol Data Units).

Learn source MAC addresses from incoming frames.

Forward frames to their destinations​​.

Analysis of Options:

Option A: Correct. Ports in the forwarding state send BPDUs to maintain network topology.

Option B: Incorrect. Ports in the forwarding state do learn source MAC addresses.

Option C: Correct. Ports in the forwarding state receive BPDUs.

Option D: Correct. Ports in the forwarding state forward data frames.

Correct Answer:B. A port in a forwarding state does not learn the source MAC address of a frame is incorrect.

Detailed Explanation:The 802.11ax standard, also known as Wi-Fi 6, supports theoretical speeds over 5 Gbit/s and is designed for high-efficiency wireless networking in dense environments. (Reference: HCIA-WLAN Training Material, IEEE 802.11 Standards)

Detailed Explanation:APs can be added to an AC using multiple methods. You can add them when they are online, offline, or allow the AC to automatically discover them. Additionally, unauthorized APs can be manually confirmed for security​.

Comprehensive Explanation: SNMP (Simple Network Management Protocol) consists of several key components:

Management Information Base (MIB): A database containing the network management data.

Managed object: The individual objects (such as interfaces or devices) that SNMP manages.

Agent process: The software running on the managed device that reports data to the NMS.

NMS (Network Management System): The centralized system that collects data from managed devices using SNMP.

All these components work together to monitor, configure, and manage network devices.

If host A already has host B’s MAC address in its ARP cache, it can send packets directly to host B without needing to perform an ARP request. This cached information allows immediate packet delivery, assuming no network changes have occurred that would invalidate the ARP entry​.

LSI (A): There is no such packet type in OSPF.

HELLO (B): These packets are used for neighbor discovery and maintaining adjacency, not for requesting LSAs.

LSACK (C): Link-State Acknowledgment (LSAck) packets confirm the receipt of LSAs but do not request missing ones.

LSR (D): Link-State Request (LSR) packets are specifically used by routers to request missing LSAs from their neighbors.

Thus, the correct answer is D (LSR).

IPv6 Anycast Address Characteristics:

Option A: True. Packets are delivered to the nearest interface based on routing distance.

Option B: False. Anycast addresses are not designed for load balancing.

Option C: True. Anycast addresses share the same address space as unicast.

Option D: True. Anycast provides redundancy by allowing multiple endpoints to share the same address​​.

Understanding Trunk Ports:

Trunk ports carry traffic from multiple VLANs.

Native VLAN (PVID) frames are sent untagged on the trunk.

Breakdown of Configuration:

port link-type trunk → Interface operates as a trunk.

port trunk pvid vlan 10 → Sets VLAN 10 as the native VLAN.

port trunk allow-pass vlan 10 20 30 40 → Allows traffic from VLANs 10, 20, 30, and 40.

Conclusion:

Since VLAN 10 is the PVID (native VLAN), frames from this VLAN are sent untagged.

Correct answer is A (VLAN 10).

References: HCIA-Datacom V1.0 Certification Guide, Chapter 4: VLANs and Trunking.

NFV Overview:NFV replaces traditional hardware appliances with software-based solutions that can be deployed on virtualized infrastructure. This allows for flexible, cost-effective, and scalable network application deployment​​.

Comprehensive Explanation: Hybrid interfaces are capable of carrying both tagged and untagged VLAN frames. They can remove VLAN tags from certain VLANs when sending data frames, depending on the configuration. The command port hybrid untagged vlan x allows a hybrid interface to transmit data frames for VLAN x without a tag, while still tagging other VLANs as required. Hybrid interfaces are flexible and can be used for trunking, but unlike pure trunk ports, they do not always require VLAN tags.

DHCP (Dynamic Host Configuration Protocol) can allocate various network parameters, including:

IP address: Assigns a unique IP to each client.

Gateway address: Provides the default gateway for routing traffic.

DNS server address: Allows domain name resolution. The DHCP server does not assign an operating system, as this is outside its scope​.

Comprehensive Explanation: Fit APs (Access Points) are designed to work in conjunction with an Access Controller (AC). They rely on the AC for configuration, management, and control of their wireless services. Without an AC, a Fit AP cannot function independently or provide wireless services. This is in contrast to Fat APs, which have their own management capabilities and can operate independently.

Direct Route (C): This has the highest priority because it represents networks directly connected to a router’s interfaces.

Static Route (B): These are manually configured but have lower priority than direct routes.

OSPF Route (D): OSPF dynamically learns routes and assigns them based on cost, but it has lower priority than direct and static routes.

RIP Route (A): RIP has the lowest priority due to its high administrative distance (120).

Priority order (from highest to lowest):Direct Route > Static Route > OSPF Route > RIP Route.

Thus, the correct answer is C (Direct Route).

For link aggregation (such as LACP) to function properly, the physical interface rates and duplex modes on each end of the aggregated link must match. This alignment ensures smooth data transfer across the aggregated link, as mismatched settings would lead to connectivity issues or performance degradation​.

Comprehensive Explanation: In STP (Spanning Tree Protocol), ports can be in several states, including:

Discarding: The port is not forwarding traffic, either because it is in a blocking state or not participating in active forwarding.

Listening: The port is processing BPDUs and is preparing to transition to either the learning or forwarding state. No data frames are forwarded during this state.

Forwarding: The port is actively forwarding traffic as part of the active network topology.

The "Disabled" state is not part of the STP protocol but rather represents a port that is administratively shut down or not participating in the STP process.

Detailed Explanation:The Priority Code Point (PCP) field in an 802.1Q VLAN tag is 3 bits long, which gives it a value range of 0 to 7. This field is used to indicate the priority of the frame, with higher values indicating higher priority​​.

Understanding Loops in Layer 2 Networks:

Layer 2 switches flood broadcast and unknown unicast packets.

If there is a loop, these packets can circulate indefinitely, leading to a broadcast storm.

Consequences of Broadcast Storms:

High CPU usage on network devices.

Degraded network performance or complete failure.

Solution:

Spanning Tree Protocol (STP) is implemented to prevent loops by selectively blocking redundant links.

Conclusion:

Since loops lead to broadcast storms, the statement is TRUE.

References: HCIA-Datacom V1.0 Certification Guide, Chapter 8: Spanning Tree Protocol.

Command Overview:The Huawei Versatile Routing Platform (VRP) uses specific commands to manage file systems and view directory contents. While the dir command is used to list files in the current directory, the pwd command is not supported in VRP environments. Instead, the current working directory is displayed as part of the command prompt in VRP​​​.

Command Analysis:

dir Command:This command is supported and displays the list of files and subdirectories in the current directory. Example:

dir

Output includes filenames, sizes, and other metadata.

pwd Command:The pwd command is commonly used in UNIX/Linux systems to print the current working directory. However, this command is not available on VRP. VRP automatically shows the current directory in its prompt, making pwd unnecessary.

Correct Answer:Since only dir is valid, the statement is false. The correct answer is B (FALSE).

Detailed Explanation:The address 145.4.2.55/26 is a valid unicast address and falls within the range of usable IP addresses for a /26 subnet. The address 237.6.1.2/24 is from a reserved range, 127.3.1.4/28 is part of the loopback range (127.0.0.0/8), and 192.168.10.112/30 only provides two usable addresses, which would not allow the router to be properly configured .

The Forward Delay timer in STP helps prevent temporary loops by setting a delay for ports transitioning through Listening and Learning states before reaching the Forwarding state. This wait period ensures that all switches have updated topology information, reducing the risk of broadcast storms or loops​.

Main Functions of Routers:Routers primarily operate at the Network Layer (Layer 3) of the OSI model, forwarding data packets based on destination IP addresses and maintaining routing tables for decision-making.

Analysis of Options:

Option A: "Routers forward data packets based on source IP addresses" is incorrect, as routers use the destination IP address in a packet to determine its forwarding path, not the source IP address​​.

Option B: "Routers enable devices on the same network segment to communicate with each other" is not a function of routers. Devices on the same segment communicate using switches or hubs, which operate at the Data Link Layer (Layer 2)​​.

Option C: "Routers forward data packets according to routing tables" is a correct function, as routers rely on routing tables to determine the best path for forwarding packets.

Option D: "Routers learn routes through multiple routing protocols and add them to the routing table" is a correct function of routers in dynamic routing scenarios​.

Correct Answer:The functions A and B are not main functions of routers.

Comprehensive and Detailed Explanation:

On Huawei VRP-based devices, the configuration file (vrpcfg.zip) is not immediately deleted when using the delete command.

Instead, it is moved to the recycle bin, ensuring accidental deletions can be recovered.

To permanently delete the file, the user must clear the recycle bin using the reset recycle-bin command.

✅ Reference: HCIA-Datacom Configuration Guide – File Management on VRP

In one-arm routing (or router-on-a-stick) mode, a single physical link (with sub-interfaces) can carry traffic between multiple VLANs, reducing the number of physical links required. This approach minimizes cabling and port usage while still enabling inter-VLAN communication. However, it does not inherently reduce IP address usage, routing table entries, or the number of devices required​.

Statement A (Correct): DR and BDR must form an adjacency relationship to maintain routing information exchange.

Statement B (Incorrect): The router with the higher priority is elected as DR, not the lower one.

Statement C (Incorrect): DR is elected by routers within a broadcast/multi-access network, not necessarily all routers in the same network segment.

Statement D (Correct): If two routers have the same priority, the one with the higher Router ID becomes the DR.

Comprehensive Explanation: The user-interface maximum-vty command is used on Huawei devices to configure the maximum number of simultaneous VTY (Virtual Terminal Line) users who can log in via Telnet. By limiting the number of VTY sessions, the administrator can control how many users are able to access the device at the same time, preventing excessive connections that may overwhelm the device or reduce security.

On Huawei routers running VRP, the reset saved-configuration command is used to delete the saved startup configuration file.

Option A (Incorrect): This command does not replace the saved configuration with the running configuration. Instead, it deletes the saved startup configuration.

Option B (Incorrect): The configuration file for the next startup is NOT retained. Instead, it is erased, meaning the device will boot with default settings if restarted.

Option C (Correct): Selecting Y (Yes) confirms the deletion of the saved startup configuration file, meaning the router will no longer have a saved configuration at the next reboot.

Option D (Incorrect): Selecting N (No) cancels the operation and keeps the saved startup configuration intact.

Thus, the correct answer is C. To clear the configuration file for next startup, select Y.

Comprehensive and Detailed Explanation:

Huawei controllers support open APIs for network programmability:✅ RESTful → Web-based API using HTTP methods.✅ OpenFlow → SDN protocol for control/data plane separation.✅ NETCONF → XML-based network configuration protocol.

❌ Incorrect Option:

AAA (Authentication, Authorization, and Accounting) is a security mechanism, NOT an open API.

✅ Reference: HCIA-Datacom SDN Guide – Open API Support

Comprehensive Explanation: In STP (Spanning Tree Protocol), the Bridge ID (BID) is used to uniquely identify a switch in the network. It consists of a bridge priority and a MAC address. A BID with a bridge priority of 0 and a MAC address starting with 00-01 is reserved for special purposes and cannot be used in a configuration BPDU (Bridge Protocol Data Unit) sent by a regular switch. This prevents conflicts with reserved MAC addresses.

SNMPv1 uses Trap messages to send unsolicited notifications about network events (e.g., failures, threshold breaches).

Response (A): Sent as a reply to SNMP queries, not proactively.

Get-Next Request (C) and Get-Request (D): These are polling requests, not proactive alarms.

Thus, the correct answer is B (Trap).

Detailed Explanation:DNS (Domain Name System) is responsible for translating human-readable domain names (like into IP addresses, enabling devices to locate services on a network. (Reference: HCIA-Datacom Training Material, DNS Function and Protocol Overview)

Detailed Explanation:Static MAC address entries are manually configured and stored in the switch's configuration file, making them persistent across reboots. These entries remain in the MAC address table after a restart, unlike dynamic entries, which are lost. (Reference: HCIA-Datacom Training Material, MAC Address Table Types)

How Routers Handle Packets:

Routers do not change the destination IP address when forwarding packets.

The destination IP remains the same to ensure the packet reaches the intended recipient.

Router’s Role:

Routers inspect the destination IP, determine the best path using routing tables, and forward the packet accordingly.

Conclusion:

The destination IP address remains unchanged; hence, the statement is FALSE.

References: HCIA-Datacom V1.0 Certification Guide, Chapter 2: IP Forwarding.

Routing Table and Equal-Cost Routes:When multiple routes to the same destination network have the same cost (e.g., metric or administrative distance), they are referred to as "equal-cost routes." Routers use load balancing to distribute traffic across these routes​​.

Analysis of Options:

Option A: "Sub-optimal routes" are routes that are not preferred due to higher cost or less desirable metrics.

Option B: "Multipath routes" is a general term but does not specify equal cost, making it less precise.

Option C: "Equal-cost routes" is correct as the scenario specifies the same destination network with the same cost.

Option D: "Default routes" are used when no specific route matches the destination, which is unrelated to the given scenario​.

Correct Answer:The routes are C (Equal-cost routes).

A (Correct): Stacking allows inter-chassis Ethernet Trunks to be created, improving redundancy and bandwidth.

B (Correct): Multiple switches act as a single logical device, simplifying network management.

C (Correct): Stacking increases available ports, allowing expansion without adding separate devices.

D (Correct): By enabling redundancy, stacking and CSS help prevent single points of failure in the network.

Thus, the correct answers are A, B, C, and D.

Detailed Explanation:With SNMP (Simple Network Management Protocol), a Network Management System (NMS) can both monitor device status and configure settings on managed devices using SNMP Set commands. (Reference: HCIA-Datacom Training Material, SNMP Protocol Functions)

In OSPF networks, a DR (Designated Router) is elected for each broadcast domain, such as each Ethernet segment. Given the topology where there are multiple Ethernet segments, a DR will be elected in each segment, resulting in three DRs based on the configuration and network design​.

An IPv4 packet consists of a header and a payload:

Total Length=Header Length+Payload Length\text{Total Length} = \text{Header Length} + \text{Payload Length}Total Length=Header Length+Payload Length

Given:

IPv4 header length = 20B

Total packet length = 1500B

Payload=1500B−20B=1480B\text{Payload} = 1500B - 20B = 1480BPayload=1500B−20B=1480B

Option A (Incorrect): 1520B is incorrect because it exceeds the total packet length.

Option B (Incorrect): 20B is just the header, not the payload.

Option C (Incorrect): 1500B includes the header, not just the payload.

Option D (Correct): 1480B is the correct payload size.

Thus, the correct answer is D (1480B).

Detailed Explanation:An MPLS (Multiprotocol Label Switching) header includes the following fields:

Label: Identifies the MPLS path.

TTL (Time to Live): Limits the lifetime of the MPLS packet.

EXP (Experimental): Used for QoS marking. The Tos (Type of Service) field is part of the IP header, not MPLS.

(Reference: HCIA-Datacom Training Material, MPLS Header Fields)

Comprehensive Explanation: To prevent unauthorized changes to the router's configuration, the administrator can take several steps. Configuring an ACL to restrict management access ensures that only authorized users, such as the administrator, can log in to the router. Additionally, using AAA (Authentication, Authorization, and Accounting) allows the administrator to manage user permissions and control access to the router's functions based on user roles. Port-security is used for limiting MAC addresses on switch ports, and login privilege levels should be set appropriately but not limited to level 0, which restricts almost all actions.

Detailed Explanation:OSPF (Open Shortest Path First) has several key advantages:

It can load balance traffic among equal-cost routes.

OSPF supports hierarchical area structures, allowing for network scalability and reduced routing table sizes.

OSPF supports strong security measures through packet authentication (MD5 or plain text).

It supports Classless Inter-Domain Routing (CIDR), allowing for more efficient IP address allocation and route aggregation.

To determine which statements are true, we need to analyze the VLAN configurations on the Huawei switch (SWA) as shown in the diagram and configuration details. We’ll evaluate each client’s VLAN membership and verify the correctness of the VLAN assignment commands based on Huawei switch configuration principles, as outlined in HCIA Datacom documentation. Let’s break it down step by step:

Understanding VLAN Assignment Types on Huawei Switches:

Huawei switches support different port link types for VLAN assignment:

Access Port: Carries traffic for a single VLAN (untagged). Typically used for end devices like PCs.

Trunk Port: Carries traffic for multiple VLANs (tagged, except for the native VLAN, which is untagged). Typically used for interconnecting switches.

Hybrid Port: Similar to a trunk port but can carry untagged traffic for specific VLANs, often used for both end devices and inter-switch links. It can tag or untag traffic based on configuration.

Additionally, Huawei supports MAC address-based VLAN assignment (using the mac-vlan command), which assigns VLAN membership based on a device’s MAC address, overriding port-based VLAN settings.

Analyzing the Configuration for Each Client:Let’s examine the configuration details for each interface connected to the clients and verify the VLAN assignments:

Client 1 (connected to GigabitEthernet0/0/1):

Configuration:

text

WrapCopy

vlan 10

#

interface GigabitEthernet0/0/1

port link-type access

port default vlan 10

The port is configured as an access port with port link-type access and assigned to VLAN 10 using port default vlan 10.

Access ports carry untagged traffic for a single VLAN, so Client 1 belongs to VLAN 10.

The commands are correct for an access port assignment to VLAN 10.

Statement C (“Client 1 belongs to VLAN 10, and the commands for VLAN assignment on the switch are correct”) is true.

Client 2 (connected to GigabitEthernet0/0/2):

Configuration:

text

WrapCopy

vlan 20

mac-vlan mac-address 0022-0022-0022 priority 0

#

interface GigabitEthernet0/0/2

port hybrid untagged vlan 20

mac-vlan enable

The port is configured as a hybrid port with port link-type hybrid and set to carry untagged traffic for VLAN 20 using port hybrid untagged vlan 20.

Additionally, mac-vlan mac-address 0022-0022-0022 priority 0 and mac-vlan enable are configured, indicating MAC address-based VLAN assignment for a device with MAC address 0022-0022-0022.

However, the diagram does not specify the MAC address of Client 2. If Client 2’s MAC address is not 0022-0022-0022, the MAC-VLAN assignment does not apply, and the port’s default VLAN (VLAN 20, untagged) determines its membership.

If Client 2 has MAC address 0022-0022-0022, it would belong to the VLAN specified by the mac-vlan command (VLAN 20, as no specific VLAN is mentioned in the mac-vlan command, implying it uses the port’s default VLAN or another configured VLAN). But since the MAC address is not provided, we assume the port-based VLAN assignment (VLAN 20) applies.

The commands appear correct for a hybrid port with untagged VLAN 20 and MAC-VLAN enabled, but the effectiveness of the MAC-VLAN depends on Client 2’s MAC address.

Statement B (“Client 2 belongs to VLAN 20, and the commands for MAC address-based VLAN assignment on the switch are correct”) is potentially true if Client 2’s MAC is 0022-0022-0022, but without confirmation, we must consider the port’s default VLAN 20. However, the MAC-VLAN priority is set to 0, which is unusual (priority 0 typically indicates the lowest priority, and Huawei recommends non-zero values for MAC-VLAN). This suggests a potential configuration error or ambiguity.

Given the lack of MAC address confirmation and the unusual priority 0, Statement B is not definitively true, as the MAC-VLAN assignment may not function as intended or may conflict with port-based VLAN 20.

Client 3 (connected to GigabitEthernet0/0/3):

Configuration:

text

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vlan 30

#

interface GigabitEthernet0/0/3

port link-type trunk

port trunk allow-pass vlan 30

The port is configured as a trunk port with port link-type trunk and allows VLAN 30 traffic using port trunk allow-pass vlan 30.

Trunk ports carry tagged traffic for specified VLANs. For Client 3 (an end device, typically not a switch), the trunk port configuration is unusual because end devices usually connect via access ports, not trunk ports. However, if Client 3 is configured to send tagged frames for VLAN 30 (e.g., a VLAN-aware device like a phone or IP camera), it can belong to VLAN 30.

The commands are correct for a trunk port allowing VLAN 30, assuming Client 3 is configured to handle tagged VLAN 30 traffic.

Statement D (“Client 3 belongs to VLAN 30, and the commands for VLAN assignment on the switch are correct”) is true, assuming Client 3 supports VLAN tagging for VLAN 30.

Client 4 (connected to GigabitEthernet0/0/4):

Configuration:

text

WrapCopy

vlan 40

#

interface GigabitEthernet0/0/4

port link-type hybrid

port hybrid untagged vlan 40

The port is configured as a hybrid port with port link-type hybrid and set to carry untagged traffic for VLAN 40 using port hybrid untagged vlan 40.

Hybrid ports can carry untagged traffic for specific VLANs, so Client 4 belongs to VLAN 40 (untagged).

The commands are correct for a hybrid port assignment to VLAN 40.

Statement A (“Client 4 belongs to VLAN 40, and the commands for VLAN assignment on the switch are correct”) is true.

Evaluating Each Statement:

A: True – Client 4 belongs to VLAN 40 (untagged on a hybrid port), and the commands are correct.

B: Not definitively true – Client 2 belongs to VLAN 20 based on the port’s hybrid untagged VLAN 20, but the MAC-VLAN configuration with priority 0 is ambiguous without Client 2’s MAC address, and the priority 0 may indicate a configuration error. Thus, we cannot confirm the MAC address-based VLAN assignment is correct.

C: True – Client 1 belongs to VLAN 10 (access port), and the commands are correct.

D: True – Client 3 belongs to VLAN 30 (trunk port, assuming tagged traffic), and the commands are correct for a trunk port allowing VLAN 30.

Conclusion:

Statements A, C, and D are true based on the configuration and VLAN assignment rules. Statement B is not definitively true due to the ambiguity of Client 2’s MAC address and the unusual priority 0 in the MAC-VLAN configuration.

Answer: A, C, D

References from HCIA Datacom Documents:

HCIA Datacom V3.0, Chapter 4: VLAN Technologies – Access, Trunk, and Hybrid Port Configurations

HCIA Datacom V3.0, Chapter 4: MAC Address-Based VLAN Assignment – mac-vlan Command and Priority Settings

Huawei VLAN Configuration Guide (HCIA Datacom Certification Material) – Port Link Types and VLAN Assignment Rules

Comprehensive and Detailed Explanation:

RADIUS (Remote Authentication Dial-In User Service) is a widely used AAA protocol for:

Authentication (verifying user credentials).

Authorization (determining access level).

Accounting (logging user activity).

It uses UDP (ports 1812/1813 or 1645/1646) and is common in enterprise networks.

✅ Reference: HCIA-Datacom Security Guide – AAA & RADIUS Overview

SNMP Agent Functionality:Each network device running SNMP includes an agent process that collects and manages information about the device's operations. This process interfaces with the SNMP manager to provide network monitoring and management capabilities​​.

Detailed Explanation:The ACL (Access Control List) configuration only permits IP address 172.16.105.2. By applying this ACL to the Telnet server, only devices from this IP can establish a Telnet connection, while all others are denied access. (Reference: HCIA-Datacom Training Material, ACLs and Telnet Access Control)

MAC Address Analysis:

MAC addresses starting with 01-00-5E are reserved for IPv4 multicast by the IANA.

Why Other Options Are Incorrect:

A: The address is valid and reserved for multicast.

C: Broadcast addresses use FF-FF-FF-FF-FF-FF.

D: Unicast addresses are typically hardware-assigned and do not use this prefix.

References: HCIA-Datacom V1.0 Certification Guide, Chapter 7: Ethernet Basics.

Detailed Explanation:In LACP (Link Aggregation Control Protocol), the Actor is elected based on device priority, interface priority, and MAC address. These parameters ensure consistency and determine the active links within the aggregated trunk. The interface number alone is not a determining factor. (Reference: HCIA-Datacom Training Material, Link Aggregation Control Protocol (LACP))

Comprehensive Explanation: In STP (Spanning Tree Protocol), the root bridge is elected based on the lowest Bridge ID. The Bridge ID consists of two parts: the bridge priority and the MAC address of the switch. The switch with the lowest Bridge ID is elected as the root bridge. If two switches have the same priority, the switch with the lowest MAC address becomes the root. Other parameters such as Port ID and Root path cost are used in subsequent decisions to determine the best paths to the root bridge, but they are not used in the root bridge election itself.

On Huawei VRP (Versatile Routing Platform), the command history feature allows administrators to recall previously executed commands. The Upper cursor key (↑ arrow key) can be used to navigate through the command history and re-execute previously entered commands.

Ctrl+P is not a valid shortcut for recalling command history.

Ctrl+U is typically used to delete an entire line of input in command-line interfaces, not to recall history.

Left cursor key (←) is used for moving the cursor within a command line but does not invoke command history.

Thus, the correct answer is B. Upper cursor key (↑ arrow key).

Device Interconnection Requirements:

Device interconnection (such as point-to-point links) requires only two IP addresses: one for each device.

A subnet mask of /30 (255.255.255.252) provides four total addresses (2 usable, 1 network, 1 broadcast).

Efficiency:

Using a /30 subnet avoids wasting IP addresses, making it ideal for point-to-point links.

Why Other Options Are Incorrect:

B (32): /32 is used for single-host IP addresses, not links.

C (24): /24 is excessive for point-to-point links, providing 254 usable addresses.

D (16): /16 provides 65,534 addresses, which is highly inefficient.

References: HCIA-Datacom V1.0 Certification Guide, Chapter 3: IP Addressing.

The wildcard mask 0.0.254.255 means:

The first and third octets are checked exactly.

The second and fourth octets can vary.

This results in a match for IPs in the range 10.0.2.0 - 10.0.2.255.

Only option D (10.0.2.1) falls within this range.

Thus, the correct answer is D (10.0.2.1).

Detailed Explanation:LSAs (Link-State Advertisements) are the fundamental OSPF messages used to convey network topology information. LSU (Link-State Update), LSR (Link-State Request), and LSACK (Link-State Acknowledgment) are all types of messages related to OSPF's operations, but "LSA" alone is not a valid OSPF message type​.

Detailed Explanation:

An edge port in RSTP (Rapid Spanning Tree Protocol) is designed to immediately transition to the forwarding state without participating in the spanning tree calculation. This allows for quicker convergence and is suitable for ports connected to end devices (not to other switches).

Comprehensive Explanation: An ACL (Access Control List) is used to define rules for permitting or denying packets based on criteria such as IP addresses, protocols, or ports. However, the ACL only takes effect when it is applied to a service module, such as an interface or a firewall rule. This ensures that traffic is filtered according to the ACL rules as it passes through the device. Without being applied, the ACL rules are inactive and do not influence traffic.

Comprehensive and Detailed Explanation:

The history-command max-size command in Huawei VRP (Versatile Routing Platform) is used to set the maximum number of previously used commands that can be saved in the command history buffer.

By default, Huawei devices store 5 previously-used commands in the buffer.

The command history-command max-size 20 increases the buffer size to 20 commands.

This does not limit the buffer to 20 bytes; instead, it allows 20 entire commands to be stored.

The correct statement that matches this behavior is:

"The history-command max-size 20 command sets the maximum of previously-used commands that can be saved in the buffer to 20."

✅ Reference: HCIA-Datacom Configuration Guide – Command Line Interface

Detailed Explanation:All listed options are valid OSPF (Open Shortest Path First) packet types:

HELLO packets establish and maintain neighbor relationships.

LSR (Link State Request) packets are used to request missing link-state information.

LSU (Link State Update) packets contain link-state advertisements for OSPF routers.

LSA (Link State Advertisement) packets carry route information.(Reference: HCIA-Datacom Training Material, OSPF Packet Types)

Analysis of Possible Causes:

Option A: "The administrator account has been disabled" is a possible cause as a disabled account cannot access the system even if Telnet is enabled.

Option B: Incorrect because the Telnet service being disabled would affect all users, not just one administrator.

Option C: "The administrator account has been deleted" is a valid reason as a deleted account cannot log in.

Option D: "The user level of the administrator account has been changed to 0" is correct. User level 0 typically has insufficient privileges for Telnet access​​.

Comprehensive and Detailed Explanation:

A static route requires the following essential parameters:

Destination Network → The network to reach (e.g., 10.1.1.0/24). ✅

Next-hop IP Address → The next router to forward traffic (e.g., 192.168.1.1). ✅

Outbound Interface → Instead of a next-hop, an interface (e.g., GigabitEthernet0/0/1) can be used. ✅

❌ Incorrect Option:

MAC address is not needed because routers forward packets based on IP, not MAC addresses.

✅ Reference: HCIA-Datacom Routing Guide – Static Routing Fundamentals

Comprehensive Explanation: OSPF (Open Shortest Path First) is a link-state routing protocol. It builds a complete map of the network's topology using Link-State Advertisements (LSAs) and makes routing decisions based on this map. Protocols like Static and Direct are not dynamic routing protocols, while FTP is a file transfer protocol

In OSPF, the "Full" state signifies that the neighbor relationship has been fully established, with both routers synchronized and their LSDBs updated. This state is achieved after exchanging and acknowledging Link State Advertisements (LSAs) between the neighbors, marking the completion of OSPF adjacency​.

Detailed Explanation:Small campus networks are characterized by simple architecture, limited user counts, and straightforward network requirements. Wide coverage is typically associated with larger campus or enterprise networks. (Reference: HCIA-Datacom Training Material, Campus Network Characteristics)

In the provided routing table, the router’s next hop for each destination indicates whether the destination is reachable directly or indirectly. For entries where the next hop is specified, the router forwards packets accordingly through the designated interface, as confirmed in the table output. This information is used to verify the forwarding behavior for each destination​.

Comprehensive and Detailed Explanation:

A default route is used when no specific route matches a destination IP.

The correct syntax for a default static route is:

ip route-static 0.0.0.0 0.0.0.0

✅ Correct Option:

A. [Huawei] ip route-static 0.0.0.0 0.0.0.0 192.168.1.1

This correctly sets 192.168.1.1 as the next-hop for all unknown destinations.

❌ Incorrect Options:

B. 0.0.0.0 0.0.0.0 0.0.0.0 → Invalid because 0.0.0.0 cannot be a next-hop.

C. 0.0.0.0 255.255.255.255 192.168.1.1 → Invalid because the mask must be 0.0.0.0 for a default route.

D. [Huawei-Serial0] ip route-static 0.0.0.0 0.0.0.0 0.0.0.0 → Invalid interface syntax.

✅ Reference: HCIA-Datacom Routing Guide – Default Route Configuration

To form an EUI-64 address, the MAC address is split and FFFE is inserted in the middle, making the EUI-64 format 00E0-FCEF-FFFE-0FEC. Additionally, the 7th bit of the first byte is flipped to form the Modified EUI-64 address used in IPv6 for Stateless Address Autoconfiguration (SLAAC)​.

Comprehensive Explanation: Host A and Host B cannot communicate because they are in different subnets. Host A's IP address is 10.0.12.1/30, while Host B's IP address is 10.0.12.5/24. Since they are in different subnet ranges and there is no router in the diagram to perform inter-subnet routing, direct communication between them is not possible without a router to route traffic between the different subnets.

Detailed Explanation:

Option B: OSPF supports triggered updates, allowing routing tables to be updated only when changes occur, conserving bandwidth.

Option D: OSPF supports area division, which is essential for optimizing large networks and limiting the scope of link-state advertisements.

Option A is incorrect because OSPF calculates the shortest path based on cost, not hop count.

Option C is incorrect; OSPF prevents routing loops by maintaining a loop-free topology through its link-state database.

(Reference: HCIA-Datacom Training Material, OSPF Features)

Detailed Explanation:The protocol number for TCP in the IPv4 header is 6. Since Telnet uses TCP as its transport layer protocol, the protocol field in the IPv4 header will contain the value 6​​.

Comprehensive and Detailed Explanation:

In Spanning Tree Protocol (STP), the root bridge is selected based on:

Lowest priority (default = 32768, lower value preferred).

Lowest MAC address (if priorities are equal).

The given bridge priorities:

SWA: 4096 (Lowest priority → Automatically the root bridge).

SWB, SWC, SWD: 32768 (Default priority).

The stp root secondary command makes SWD the backup root (if SWA fails).

✅ Reference: HCIA-Datacom Switching Guide – STP Root Bridge Selection

To determine which switch will be selected as the root bridge after running the stp root secondary command on SWD, we need to analyze the Spanning Tree Protocol (STP) election process, as defined in IEEE 802.1D and aligned with HCIA Datacom documentation. Let’s break it down step by step:

Understanding STP and Root Bridge Election:

STP is used to prevent loops in Ethernet networks by electing a root bridge and creating a loop-free topology. The root bridge is the central point of the spanning tree, and all other switches calculate the shortest path to it based on path cost.

The root bridge is selected based on the Bridge ID (BID), which consists of two components:

Bridge Priority: A 16-bit value (default is 32768 for most switches, but it can be configured). Lower priority values are preferred.

MAC Address: If bridge priorities are equal, the switch with the lowest MAC address (the last part of the Bridge ID) becomes the root bridge.

The Bridge ID is typically written as Priority:MAC-Address. For example, a Bridge ID of 4096:0001-0203-04AA indicates a priority of 4096 and a MAC address of 0001-0203-04AA.

Analyzing the Given Bridge IDs:From the diagram, the Bridge IDs of the switches are:

SWA: Bridge ID = 4096:0001-0203-04AA (Priority = 4096, MAC = 0001-0203-04AA)

SWB: Bridge ID = 32768:0001-0203-04BB (Priority = 32768, MAC = 0001-0203-04BB)

SWC: Bridge ID = 32768:0001-0203-04CC (Priority = 32768, MAC = 0001-0203-04CC)

SWD: Bridge ID = 32768:0001-0203-04DD (Priority = 32768, MAC = 0001-0203-04DD)

Initially, the switch with the lowest Bridge ID (lowest priority, or lowest MAC if priorities are tied) is elected as the root bridge.

Comparing the priorities:

SWA has a priority of 4096, which is lower than the default priority of 32768 for SWB, SWC, and SWD.

Therefore, SWA is currently the root bridge because it has the lowest priority (4096) compared to the others (32768).

If priorities are equal, the MAC address is used as a tiebreaker, but here, SWA’s lower priority makes it the root bridge without needing to compare MAC addresses.

Effect of the stp root secondary Command on SWD:

The stp root secondary command (commonly used in Huawei switches, as per HCIA Datacom) is a configuration command that sets a switch as the secondary root bridge. This means the switch’s priority is automatically adjusted to a value lower than the default (32768) but higher than the primary root bridge’s priority, ensuring it becomes the root bridge if the primary root fails.

Specifically, in Huawei switches, running stp root secondary on SWD typically sets its priority to 28672 (which is lower than 32768 but higher than 4096, ensuring it does not override SWA unless SWA fails).

However, the question asks which switch will be selected as the root bridge after running this command on SWD, implying we need to determine the current root bridge and whether this command changes it immediately.

Importantly, the stp root secondary command does not immediately make SWD the root bridge if a switch with a lower priority (like SWA with 4096) already exists in the network. It only prepares SWD to become the root if the current root (SWA) fails or is removed.

Therefore, running stp root secondary on SWD adjusts its priority to 28672, but SWA remains the root bridge because its priority (4096) is still lower than SWD’s new priority (28672).

Determining the Root Bridge After the Command:

After running stp root secondary on SWD, its Bridge ID becomes 28672:0001-0203-04DD (Priority = 28672, MAC = 0001-0203-04DD).

We compare the Bridge IDs of all switches:

SWA: 4096:0001-0203-04AA (Priority = 4096)

SWB: 32768:0001-0203-04BB (Priority = 32768)

SWC: 32768:0001-0203-04CC (Priority = 32768)

SWD: 28672:0001-0203-04DD (Priority = 28672)

The switch with the lowest priority (and lowest MAC address if priorities are tied) is the root bridge.

SWA’s priority (4096) is the lowest, followed by SWD’s new priority (28672), and then SWB and SWC (32768).

Therefore, SWA remains the root bridge because its priority (4096) is lower than SWD’s new priority (28672) and all others.

Conclusion:

Initially, SWA is the root bridge due to its lowest priority (4096).

Running stp root secondary on SWD changes its priority to 28672, making it the secondary root (backup root) if SWA fails, but it does not immediately make SWD the root bridge.

Thus, SWA continues to be the root bridge after the command is run on SWD.

Answer: B (SWA)

References from HCIA Datacom Documents:

HCIA Datacom V3.0, Chapter 6: Spanning Tree Protocol – Root Bridge Election and Configuration Commands

Huawei STP Configuration Guide (HCIA Datacom Certification Material) – stp root primary and stp root secondary Commands

IEEE 802.1D Standard – Bridge ID and Root Bridge Selection Process

Detailed Explanation:In Huawei VRP, the command-privilege command is used to modify the privilege level of a specific command. In this case, the command adjusts the privilege level of the save command within the user view to level 3, which is higher than the default level. This command does not modify the user's privilege level itself but changes the required privilege level to use the save command in the user view .

Static IP addressing for servers in campus network planning is crucial for maintaining stable network access to server resources. Static IPs ensure that critical devices like servers have fixed addresses, allowing for predictable network access and reducing potential IP conflicts, which enhances network reliability. This practice is endorsed in Huawei's guidelines for effective campus network design and is considered a best practice for managing servers on a network​.

Restoring factory defaults on an AR2200 router requires both clearing the current configuration and resetting saved configurations. These steps ensure that any custom settings are removed, reverting the router to its original state. Simply restarting or specifying a startup file without clearing configurations would not remove custom settings​.

Detailed Explanation:Static routing does not automatically recover from link failures; manual reconfiguration is required if a static route path becomes invalid. Dynamic routing protocols, on the other hand, adapt automatically to network changes, adjusting routes as needed. (Reference: HCIA-Datacom Training Material, Static vs. Dynamic Routing)

In Spanning Tree Protocol (STP), Topology Change (TC) BPDUs are used to notify switches about network topology changes.

The Root Bridge generates BPDUs with TC bits set, which are forwarded through the network.

Non-root switches forward these BPDUs through their Designated Ports.

Option A (Incorrect - Root Port): The Root Port receives BPDUs from the Root Bridge but does not forward them.

Option B (Correct - Designated Port): Designated ports are responsible for forwarding BPDUs down the tree towards other switches.

Option C (Incorrect - Backup Port): Backup ports are blocking and do not forward BPDUs.

Option D (Incorrect - Alternate Port): Alternate ports are in a blocking state and do not forward BPDUs.

Thus, the correct answer is B.

Encapsulation is the process of adding headers and trailers to data at each layer of the OSI model as the data moves from the application layer to the physical layer. Decapsulation is the reverse process when data is received. These processes are critical in implementing network communication, ensuring the proper function of protocols, and assisting in locating faults during data transmission. They do not, however, shorten packet length​

The configuration provided is for a trunk port, which can carry multiple VLANs.

The command port trunk allow-pass vlan 10 20 30 40 allows tagged traffic from VLANs 10, 20, 30, and 40.

The command port trunk pvid vlan 10 sets the PVID (Port VLAN ID) to VLAN 10.

Any untagged frames received on this port will be assigned to VLAN 10, as per the PVID setting.

Option A (Correct): Since the PVID is VLAN 10, untagged frames are assigned to VLAN 10.

Options B, C, and D (Incorrect): VLANs 20, 30, and 40 are allowed, but untagged frames are not assigned to them.

Thus, the correct answer is A.

A (Correct): The client initiates the connection using a random source port (50190).

B (Correct): The packets show the TCP three-way handshake (SYN, SYN-ACK, ACK).

C (Incorrect): The client initiates the connection (10.0.12.1), and the server responds (10.0.12.2), so the roles are reversed in this statement.

D (Correct): The handshake packets contain no application-layer data, only TCP control flags.

Thus, the correct answer is C (False Statement).

Comprehensive Explanation: In STP, the switch with the lowest Bridge ID is selected as the root bridge. The Bridge ID consists of the bridge priority and the MAC address. In this case, the switch with the bridge priority of 4096 has the lowest Bridge ID, making it the root bridge. If two switches have the same bridge priority, the MAC address is used to break the tie, with the lower MAC address winning.