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

In VRP, the "-a" parameter in the ping command allows specifying a source IP address for the echo request. This can be helpful in testing connectivity from a specific interface on the device, which is useful in verifying path accessibility or troubleshooting issues with certain network segments​.

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)

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​

Comprehensive Explanation: When Router A forwards the packet to Router B, the destination IP address (11.0.12.1) remains unchanged as it is still meant for Host B. However, the destination MAC address changes to MAC-B, which belongs to Host B, since MAC addresses are only used for local network hops​

LACP Active Interface Election Overview:In LACP mode, active interfaces are elected based on interface priorities. If the interface priorities are identical, the system compares the interface numbers, and the one with the smaller number is preferred.

Analysis of Options:

Option A: Incorrect because interface priorities alone are insufficient when multiple interfaces share the same priority.

Option B: Device priorities are not used in this scenario for selecting active interfaces.

Option C: Correct. This process aligns with the behavior described for LACP, where interface priorities are compared first, and interface numbers are used as a tie-breaker.

Option D: Incorrect because interface numbers are only used as a secondary criterion.

Correct Answer:C. Interface priorities are compared first. If priorities of interfaces on the Actor are the same, interfaces with smaller interface numbers are elected as active interfaces​​.

Detailed Explanation:Huawei AR G3 series routers support various AAA authentication modes including RADIUS, local authentication, no authentication (None), and 802.1X. These modes offer flexibility in how users are authenticated for network access depending on the security requirements​​.

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​.

Router Functionality:Routers operate at the Network Layer (Layer 3) of the OSI model. They use IP addresses to forward packets between different networks and determine the best path for data transmission based on routing tables​​.

Analysis of Options:

Option A: "Network layer" is correct, as routers are Layer 3 devices.

Option B: "Transport layer" handles end-to-end communication and reliability (e.g., TCP/UDP), not routing.

Option C: "Data link layer" is for local node-to-node data transfer (e.g., MAC addresses), handled by switches.

Option D: "Application layer" is for user-facing software interactions (e.g., HTTP, FTP).

Correct Answer:Routers work at the A (Network layer).

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.

Bridge Priority Overview:

Bridge Priority is a key parameter in Spanning Tree Protocol (STP) and is used to elect the root bridge.

The default bridge priority for Huawei switches is 32768, which is the default for many vendors.

How STP Uses Bridge Priority:

Lower bridge priority values are preferred during root bridge elections.

Administrators can modify this value for desired root bridge placement.

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

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​.

Comprehensive Explanation: In RSTP (Rapid Spanning Tree Protocol), the Alternate Port is the backup path to the root bridge. If the current root port fails, the Alternate Port immediately transitions to the forwarding state, providing a new path to the root bridge with minimal delay. This rapid transition is one of the key improvements of RSTP over the older STP protocol. Backup ports, on the other hand, provide redundancy on the same switch, and edge ports are used to connect directly to end devices.

Detailed Explanation:Each Virtual Access Point (VAP) on an AP is identified by a unique Basic Service Set Identifier (BSSID), which is the MAC address used at the data link layer. The SSID is a human-readable network name, while the BSSID is the technical identifier​.

Detailed Explanation:In a Spanning Tree Protocol (STP) environment, the root bridge is selected based on the bridge ID. Here, SWA has the lowest bridge ID (4096:0001-0203-04AA), making it the root bridge. For each network segment, STP elects one designated port to forward traffic, and all other ports in that segment will be blocked to prevent loops.

Following the STP rules:

SWA is the root bridge, so all of its ports (G0/0/2 and G0/0/3) will be designated ports.

Each non-root switch (SWB and SWC) selects one root port, which is the port with the lowest path cost to the root bridge (SWA).

SWB's G0/0/3 will have a higher path cost when compared with G0/0/1 (if assuming equal link costs), thus making G0/0/1 the root port on SWB.

SWB will then block its G0/0/3 port to prevent a loop, as SWA's G0/0/3 is already the designated port for that link.

Hence, G0/0/3 of SWB will be in the blocking state to maintain a loop-free topology

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)

Detailed Explanation:Using DHCP provides several advantages:

It helps prevent IP address conflicts because the DHCP server dynamically assigns IP addresses, ensuring each device gets a unique one.

IP addresses can be reused by setting lease times, allowing the DHCP server to recycle addresses from devices that no longer need them.

Centralized configuration management is also possible. If network configuration details such as the DNS server change, the administrator can update these settings on the DHCP server, and all DHCP clients will automatically receive the new information​​.

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.

Routers can learn routes from various sources:

Static routes: Manually configured routes.

Direct routes: Routes to networks directly connected to the router.

Summary routes: Aggregated routes summarizing multiple networks, often used in routing protocols.

Dynamic routes: Routes learned via routing protocols like OSPF, RIP, or BGP. These sources contribute to the router's routing table, enabling it to forward packets to known destinations​.

Detailed Explanation:In a tree topology, nodes are arranged hierarchically with root nodes at the top and leaf nodes at the base. This structure is often used in larger networks because it supports scalability and easy addition of nodes. However, if a higher-level node (e.g., root or intermediate node) fails, all dependent nodes in its subtree lose connectivity. Therefore, faults at higher layers have a more significant impact than faults at the leaves. (Reference: HCIA-Datacom Training Material, Network Topology Types)

Detailed Explanation:In manual load balancing mode, all active interfaces forward traffic, distributing it evenly across links without LACP. This allows for static load balancing. Option B is incorrect because LACP (Link Aggregation Control Protocol) is not involved in manual mode. (Reference: HCIA-Datacom Training Material, Link Aggregation and Manual Load Balancing)

A floating static route is configured by assigning a higher preference value to the backup route. This ensures that the backup route (floating route) is used only when the primary route is unavailable. Lower preference values indicate higher priority​.

Comprehensive Explanation: A routing table contains several key elements:

Cost: Also known as metric, this indicates the cost associated with reaching a specific destination, such as the number of hops or link speed.

Next-hop address: This is the IP address of the next device along the route that packets should be forwarded to.

Protocol: The routing protocol (e.g., OSPF, RIP) that determined the route.

Interface: The physical or logical interface through which the router sends packets to reach the destination.

Destination/Mask: The destination network or subnet and the associated subnet mask define the range of IP addresses for which this route is valid. These elements together allow routers to efficiently forward traffic to the correct destinations.

Comprehensive Explanation: In Telnet sessions, different privilege levels determine what actions a user is allowed to perform. If users are not able to configure the IP address, it is likely that their privilege level is set incorrectly. The administrator must ensure that the Telnet users are assigned the correct privilege level (typically level 15 for full administrative rights) to allow configuration changes, including IP address modifications.

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 RSTP (Rapid Spanning Tree Protocol), the Backup port serves as a backup for the Designated port on the same bridge segment, not the root port. If the root port fails, the alternate port, not the backup port, takes over to maintain connectivity to the root bridge. The backup port does not have the capability to replace the root port​.

In a many-to-many non-NAPT (Network Address Port Translation) configuration, each private host requires a unique public IP address from the address pool. If only two public IP addresses are available and both are already in use by Host A and Host B, no IP will be available for Host C, preventing it from accessing the public network​.

Comprehensive Explanation: In Software-Defined Networking (SDN), the control plane (which makes decisions about where to send traffic) is separated from the forwarding plane (which actually moves packets to their destinations). This separation allows for centralized control and management of the network, enabling programmability and greater flexibility. SDN controllers manage the control plane, while individual switches or routers handle the forwarding of data.

The Bridge ID, a combination of bridge priority and MAC address, is used to determine the root bridge in STP. The switch with the lowest Bridge ID becomes the root bridge. If bridge priorities are identical, the switch with the lowest MAC address is selected as the root bridge​.

Trunk Interface Basics:

Trunk interfaces are used to carry traffic for multiple VLANs between switches.

Tagged frames include VLAN identifiers, while untagged frames belong to the native VLAN.

Untagged Frames:

Frames from the native VLAN are sent untagged on the trunk interface.

Conclusion:

Trunk interfaces support both tagged and untagged frames, so the statement is TRUE.

References: HCIA-Datacom V1.0 Certification Guide, Chapter 4: VLAN Basics.

Detailed Explanation:The Type/Length field value of 0x0800 indicates that the upper-layer protocol is IPv4. However, the length of the IPv4 header can range from 20 to 60 bytes, not the length of the entire upper-layer packet. The field refers to the type of the encapsulated protocol, and the length is not constrained to the header alone​​.

IPv6 Address Types:

Unicast: Identifies a single interface.

Anycast: Identifies a set of interfaces, delivering to the nearest one.

Multicast: Delivers to multiple interfaces.

Broadcast: Does not exist in IPv6; replaced by multicast addressing​​.

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: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)

Detailed Explanation:

Dynamic routing protocols, such as OSPF and RIP, automatically discover and generate routes, adjusting when network topology changes occur. This helps in reducing the manual configuration required by static routes and ensures that the network adapts efficiently to changes such as link failures or the addition of new routes.

Configuration Analysis:

The router has two DHCP pools (pool1 and pool2).

Interface Gi/0/0 is assigned the IP address 10.10.10.1/24 and is configured to use global DHCP.

Reasoning:

The IP address 10.10.10.1 indicates that the interface belongs to the 10.10.10.0/24 network segment.

DHCP assigns IP addresses based on the network of the interface. Therefore, the host will receive an IP address from pool1 (10.10.10.0/24).

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​.

In OSPF, the Backup Designated Router (BDR) is selected based on the highest priority and, in case of a tie, the highest router ID. Given that Router D has the appropriate settings, it is designated as the BDR, providing backup for the DR (Designated Router) in this network configuration​.

In RSTP, both alternate and backup ports do not forward user traffic, but they can still receive and process BPDUs (Bridge Protocol Data Units). This allows the network to quickly reconfigure if the active path fails, as these ports are already participating in spanning tree calculations​.

The telnetlib module in Python provides functions to interact with Telnet servers, allowing Python scripts to automate Telnet sessions. This module is widely used in network automation and scripting tasks, where Telnet is used to access and manage network devices remotely​.

Dynamic Routing Protocol Purpose:A dynamic routing protocol's primary function is to dynamically generate and maintain routing tables by learning and sharing routing information between routers in real time. This ensures efficient path selection and adaptation to network changes​​.

Analysis of Options:

Option A: "Generate an IP address" is unrelated to routing protocols; IP address assignment is handled by DHCP or manual configuration.

Option B: "Manage routers" is inaccurate, as dynamic routing protocols do not manage router hardware or administrative tasks.

Option C: "Generate a routing table" is correct because routing protocols dynamically compute and update routing tables based on network topology changes.

Option D: "Control the status of router interfaces" refers to interface management, which is not a function of dynamic routing protocols.

Correct Answer:The main function of a dynamic routing protocol is C (Generate a routing table).

Detailed Explanation:In Python, the telnetlib module is indeed used to implement the Telnet protocol, providing functionality for interacting with remote devices over Telnet​.

An Ethernet II frame has a standard length range of 64 to 1518 bytes, including the Ethernet header. This range accounts for both the minimum frame size (to prevent collisions) and the maximum frame size (to avoid excessive delay). This specification is in line with IEEE 802.3 standards for Ethernet frames​.

Comprehensive Explanation: Router Advertisement (RA) packets in IPv6 are part of the Neighbor Discovery Protocol, which uses ICMPv6 (Internet Control Message Protocol for IPv6). RA messages are sent by routers to inform hosts about the presence of routers on the network and provide them with information needed for stateless address auto-configuration, such as the network prefix and default gateway.

Detailed Explanation:In this scenario, the MAC address 00e0-fc99-9999 is associated with multiple IP addresses through dynamic ARP learning, indicating that the host’s IP has changed several times. The ARP table on the switch shows multiple entries with different IPs mapped to the same MAC address, which is common when a device frequently updates its IP. As ARP is a dynamic protocol, these entries reflect the device's current and past IP associations. (Reference: HCIA-Datacom Training Material, ARP Operation and IP-MAC Mapping)

In STP, a port moves from Learning to Forwarding state after the Forward Delay timer has expired. This delay ensures stability by allowing time for the topology to converge before the port begins forwarding user traffic, thereby preventing loops in the network during the transition​.

In the IP header at the network layer, the Protocol field specifies the transport layer protocol in use. The protocol number for UDP is 17, not 6. Protocol number 6 is reserved for TCP. This field allows IP packets to be correctly processed by the appropriate transport-layer protocol at the receiving device​.

Detailed Explanation:In a "one-armed routing" setup, a router with sub-interfaces can handle inter-VLAN routing by logically segmenting traffic within a single physical interface. In this configuration, each department (Administration and Finance) is assigned a different VLAN with separate sub-interfaces on Router R1.

In such a setup, communication between different VLANs (i.e., inter-VLAN routing) is handled by the router, even without Proxy ARP enabled. The router can directly route packets between the VLANs as it is aware of the different networks and performs Layer 3 forwarding based on the IP address of each VLAN's sub-interface.

Thus, even if ARP Proxy is disabled, devices in the Administration and Finance departments can communicate through the router because inter-VLAN routing takes place at Layer 3 without relying on ARP proxy functionality​​​.

Detailed Explanation:RSTP (Rapid Spanning Tree Protocol) combines the Blocking, Listening, and Disabled states into Discarding, reducing the number of states to Discarding, Learning, and Forwarding. RSTP does not use a separate Listening state, as in standard STP. (Reference: HCIA-Datacom Training Material, RSTP Port States)

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).

Detailed Explanation:When a command entered on Huawei’s Versatile Routing Platform (VRP) is incomplete, VRP generates an error message indicating that the command is incomplete at a specific position (designated by 'A'). This message helps administrators identify where additional parameters are needed to complete the command syntax. Other error messages indicate issues such as excess parameters or ambiguous commands. (Reference: HCIA-Datacom Lab Guide, VRP Command Syntax)

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.

Detailed Explanation:The default Router Dead Interval in OSPF is 40 seconds for broadcast and point-to-point networks. This interval defines the time period a router waits to receive hello packets before declaring a neighbor as down. (Reference: HCIA-Datacom Training Material, OSPF Hello and Dead Intervals)

In OSPF, a router in the backbone area (Area 0) has a full LSDB (Link-State Database) for all routers within the OSPF domain. This comprehensive LSDB allows the backbone area to communicate effectively with other areas by providing routing information about all connected OSPF routers, facilitating inter-area routing​.

Understanding Switch Stacking:

Switch stacking allows multiple physical switches to operate as a single logical switch.

Huawei iStack technology supports stacking multiple switches.

Benefits of Stacking:

Simplified Management: Single configuration and management point.

Increased Redundancy: Failover and link aggregation improve reliability.

Scalability: More switches can be added as needed.

Conclusion:

More than two switches can be stacked, making the statement TRUE.

References: HCIA-Datacom V1.0 Certification Guide, Chapter 9: Huawei iStack.

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​​.

Error Analysis:The error message indicates that the command entered is not recognized by the device. This typically occurs when the syntax is incorrect or the first keyword of the command is unrecognized. The system identifies the problem location ('A' position), which points to the initial part of the command.

Analysis of Options:

Option A: "The entered parameter is not specified" refers to cases where a valid command is incomplete due to missing parameters, not an unrecognized command. This is unrelated to the error displayed.

Option B: "The entered command is incomplete" applies when additional parameters are needed to complete the command. However, the system explicitly states "unrecognized command," ruling this out.

Option C: "The parameter type is incorrect" refers to an error where a parameter is of the wrong type (e.g., string instead of integer). This is not related to keyword recognition.

Option D: "No keyword is found" directly aligns with the error message, as the system cannot recognize the first keyword of the command, making it the correct answer​​.

In trunk mode, the interface can forward frames tagged with VLANs specified in the allow-pass list (here, VLAN 100) without removing tags. However, if an untagged frame is received, it is assigned to the PVID (here, VLAN 200). This configuration allows both tagged and untagged traffic, with the PVID determining the VLAN for untagged frames​.

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

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.

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: The command dot1q termination vid 100 in the configuration specifies that the sub-interface is configured to receive tagged data frames for VLAN 100. VLAN tagging ensures that frames are properly identified and routed through the correct VLAN, and the sub-interface is associated with a specific VLAN ID to handle the tagged traffic.

Comprehensive Explanation: A routing table contains information necessary for the router to determine the best path to forward packets. This includes the destination network or subnet (Destination/Mask), the next-hop address (the IP address of the next device in the path), and the cost (metric) associated with the route. MAC addresses are used at the Data Link layer (Layer 2) for local network communication and are not part of the routing table, which operates at the Network layer (Layer 3).

Detailed Explanation:The command forward-mode direct-forward is used to configure the AC to enable direct forwarding, meaning that the AP will forward user data packets directly to the network without tunneling them through the AC, improving efficiency by reducing the load on the AC​.

Switches generally operate at the data link layer (Layer 2) and are used to manage communication within a local area network (LAN) by directing traffic among devices. They are not usually deployed as egress devices, which are typically routers. Switches facilitate internal LAN communication, while egress devices handle traffic leaving the network​.

Detailed Explanation:Making a call on a landline telephone involves network communication. Though it uses a traditional telephone network (Public Switched Telephone Network, PSTN), the process of sending and receiving voice data through a wired system qualifies as network communication. The voice signals are converted into electrical signals, transmitted over the network, and then converted back into voice signals on the receiving end .