Huawei H12-831 Exam Dumps & Practice Test Questions

Question 1:

Is it true that Bidirectional Forwarding Detection (BFD) can be used with IS-IS to significantly reduce the time taken to detect link failures in a network?

A. TRUE
B. FALSE

Correct Answer: A

Explanation:

In networking, one critical factor in maintaining high availability and minimal downtime is how quickly routing protocols can detect a link or neighbor failure and reconverge to an alternative path. IS-IS (Intermediate System to Intermediate System) is a robust interior gateway protocol (IGP) used especially in large-scale networks. However, its native failure detection mechanism—based on Hello packets—can introduce a delay in recognizing failed links.

By default, IS-IS Hello packets are exchanged every 10 seconds, and a neighbor is declared down after three missed Hellos, resulting in a potential 30-second delay before rerouting begins. For many modern networks, especially service providers or financial institutions, this duration is unacceptable because it can disrupt real-time services such as VoIP, video, or financial transactions.

This is where Bidirectional Forwarding Detection (BFD) becomes valuable. BFD is a lightweight, fast protocol designed to detect faults between two forwarding devices in a network, regardless of the data path. It functions independently of the routing protocol and operates at much faster intervals—typically detecting failures within 50 milliseconds.

When IS-IS is integrated with BFD, BFD sessions are established between IS-IS peers. If BFD detects that the link or the peer is down, it immediately notifies the IS-IS process. This enables IS-IS to react much faster by withdrawing routes associated with the failed neighbor and initiating faster convergence to alternative paths.

This integration is highly beneficial in scenarios that demand rapid failover and minimal packet loss, such as in backbone networks or data centers. Moreover, BFD supports unidirectional detection, meaning it can identify failures in one direction that IS-IS Hello packets might miss, further enhancing network reliability.

Most modern networking equipment from vendors like Cisco, Juniper, and Nokia support IS-IS and BFD integration. It is considered best practice in performance-sensitive environments to deploy BFD alongside IGPs for faster failure detection and improved resiliency.

In summary, combining IS-IS with BFD dramatically improves the responsiveness of the network to failures by decreasing detection and convergence time from seconds to milliseconds, thereby ensuring more stable and efficient operations.

Question 2:

Is it correct that an ABR in an OSPF Not-So-Stubby Area (NSSA) always translates every Type 7 LSA into a Type 5 LSA?

A. TRUE
B. FALSE

Correct Answer: B

Explanation:

OSPF (Open Shortest Path First) is a widely used link-state routing protocol that categorizes its network into various area types to optimize routing and reduce overhead. One such specialized area is the Not-So-Stubby Area (NSSA), which allows for limited external route advertisement while maintaining the benefits of a stub area.

Within an NSSA, routers—specifically Autonomous System Boundary Routers (ASBRs)—can import external routes into OSPF using Type 7 LSAs (Link-State Advertisements). These LSAs are unique to NSSA and are intended to carry external route information without flooding the area with traditional Type 5 LSAs, which are used in standard areas for external routing.

However, since routers in other OSPF areas do not recognize Type 7 LSAs, these must be translated into Type 5 LSAs by an Area Border Router (ABR)—a router that connects the NSSA to the backbone area (Area 0). But this translation process is conditional, not automatic for all Type 7 LSAs.

The key lies in the P-bit (Propagate bit) present in the Type 7 LSA. Only if this bit is set does the ABR consider the LSA eligible for conversion into a Type 5 LSA. If the P-bit is not set, the ABR will not perform the translation, and the LSA remains confined within the NSSA. Therefore, not every Type 7 LSA gets converted—only those explicitly marked for propagation.

Additionally, to avoid multiple ABRs translating the same LSA and causing redundant external advertisements, OSPF implements a deterministic selection process. This ensures that only one ABR is responsible for converting any particular Type 7 LSA to a Type 5 LSA, based on factors such as router ID and priority.

In essence, while ABRs have the capability to translate Type 7 LSAs into Type 5, they do not convert all such LSAs—only those with the appropriate P-bit setting and only when elected to perform the translation. Therefore, the notion that ABRs convert every Type 7 LSA is inaccurate.

This makes the correct answer B (FALSE), because the translation is selective, not universal.

Question 3:

Which of the following statements does not accurately describe the capabilities of IP Source Guard (IPSG)?

A. IPSG can help mitigate IP address spoofing threats
B. IPSG applies IP filtering on Layer 3 interfaces
C. IPSG enables IP packet inspection and integrates with network management systems for alerting
D. IPSG blocks devices from assigning themselves unauthorized IP addresses

Correct Answer: C

Explanation:

IP Source Guard (IPSG) is a security feature commonly deployed on access switches to prevent IP address spoofing on untrusted Layer 2 ports. It relies heavily on DHCP snooping to build a table of valid IP-to-MAC bindings, which are then used to validate incoming packets on the switch. This ensures that only traffic from legitimate sources is permitted.

Let’s evaluate each statement:

• Option A is accurate. One of IPSG’s core functions is to protect against IP address spoofing attacks. It checks if incoming packets on a port have a matching IP-to-MAC binding and drops any packets that fail this validation. This makes it an effective measure to stop attackers from impersonating legitimate hosts using false IP addresses.

• Option B is also true. IPSG functions as a Layer 3 security control and is implemented on Layer 3 interfaces, though it evaluates Layer 2 (MAC) and Layer 3 (IP) bindings. This dual-layer validation ensures tighter control over access to the network based on IP address legitimacy.

• Option C, however, is incorrect. This option falsely attributes capabilities like packet inspection and alerting integration with network management systems to IPSG. These functions are typically the responsibility of more advanced systems such as Intrusion Detection Systems (IDS) or Intrusion Prevention Systems (IPS). IPSG’s operation is limited to filtering based on IP/MAC bindings—it does not inspect payloads, analyze packet content, or raise alarms.

• Option D is correct. IPSG can effectively prevent hosts from manually configuring an IP address not authorized via DHCP. If a device attempts to assign itself an unapproved IP, IPSG will drop its traffic because it lacks a valid DHCP snooping binding.

In summary, IPSG is not a deep inspection tool. It is strictly a filtering mechanism that relies on trusted IP/MAC bindings. The incorrect statement is Option C, as it inaccurately describes IPSG as performing actions it was not designed to handle, such as packet-level inspection and integration with alerting systems.

Question 4:

Which of the following is not a valid security action triggered by a violation of port security involving a secure MAC address?

A. Protect
B. Restrict
C. Shutdown
D. Remark

Correct Answer: D

Explanation:

Port security is a feature used on network switches to restrict access to ports based on MAC addresses. When secure MAC addresses are configured on a port, the switch monitors the devices that try to communicate through that port. If an unauthorized device attempts to send traffic, the switch can respond using one of several predefined actions.

Here’s a breakdown of the valid responses:

• Protect (Option A): This is a permissive action. If an unknown MAC address sends traffic through the port, the switch silently drops the packet. There is no logging or alert, and the port remains active. This action provides security without triggering unnecessary administrative overhead.

• Restrict (Option B): This is a more alert-driven action. Similar to Protect, the packet is dropped if it comes from an unrecognized MAC address, but the event is logged. Additionally, optional notifications like SNMP traps can be triggered to inform network administrators. This allows for real-time awareness of policy violations.

• Shutdown (Option C): This is the most aggressive security action. The port is placed into an error-disabled state, effectively shutting it down when a violation occurs. Manual intervention is typically required to re-enable the port. This is used in highly secure environments where any anomaly should immediately be blocked and flagged.

Now let’s consider Option D: Remark. This option is not a valid port security action. The term “remark” generally refers to marking packets (often for Quality of Service, or QoS) or adding comments in configuration files—it has no role in the enforcement of MAC address-based port security policies. A switch cannot respond to MAC address violations using a "remark" action, making this option incorrect in the context of port security.

Therefore, Remark does not belong in the list of valid port security actions, unlike Protect, Restrict, and Shutdown, which are officially recognized by most switch vendors like Cisco and Huawei.

Question 5:

In an IS-IS routing environment with multiple redundant paths and equal-cost routes, which of the following descriptions is incorrect regarding traffic forwarding behavior?

A. If the number of equal-cost routes discovered exceeds the configured limit and all have equal priority, the route through the next-hop with the higher System ID will be chosen.
B. Enabling negative arbitration will ensure traffic is evenly split across all available links.
C. When route priority is configured, IS-IS forwards traffic exclusively to the route with the highest priority rather than balancing the load.
D. IS-IS allows each equal-cost path to be assigned a priority, using the highest one for forwarding while keeping others as backups.

Correct Answer: B

Explanation:

IS-IS (Intermediate System to Intermediate System) is a robust interior gateway protocol (IGP) commonly used in service provider and large-scale enterprise networks. It supports equal-cost multipath (ECMP) routing, allowing traffic to be forwarded across multiple paths that have the same cost, which enhances redundancy and network utilization.

Let’s evaluate each statement for accuracy:

Option A is accurate. In scenarios where IS-IS discovers more ECMP routes than the maximum number configured (e.g., if the device supports 4 paths but finds 6), it must choose among them. When all routes have the same priority, IS-IS uses the next-hop System ID as a tiebreaker. The route with the higher System ID is preferred. This ensures a deterministic and predictable selection process.

Option C is also valid. If an administrator explicitly configures priorities for equal-cost routes, IS-IS no longer performs load balancing across all paths. Instead, it selects the highest-priority route for forwarding traffic. The lower-priority paths become standby or backup routes. This behavior supports policy-based routing and ensures controlled traffic engineering.

Option D is correct as well. IS-IS allows per-route priority assignments for ECMP paths. The route with the highest priority is used actively, while the others are treated as backups. This provides flexibility for network designers to prefer specific links while maintaining fault tolerance.

Option B is the incorrect statement. The concept of negative arbitration is not part of IS-IS protocol standards. IS-IS does support ECMP load balancing, but it does so through standard mechanisms like per-packet or per-flow load sharing, depending on the router’s capabilities. There is no such configuration as "negative arbitration" in IS-IS, and it does not influence how traffic is distributed across links.

In conclusion, the term used in Option B is nonexistent within the context of IS-IS routing. It describes a fabricated or incorrectly used concept, making it factually incorrect. IS-IS uses well-defined, standard mechanisms for ECMP handling without any notion of negative arbitration.

Question 6:

Which two of the following features are fundamental to Huawei’s CloudEngine switch series? (Select two)

A. Support for SDN-based architectures
B. Native integration with FusionSphere virtualization
C. Use of high-speed ASICs for packet processing
D. Embedded WLAN controller functionality
E. Complete Layer 2 and Layer 3 MPLS support

Correct Answers: A and C

Explanation:

Huawei’s CloudEngine series is engineered for high-performance networking in modern data centers and enterprise backbone infrastructures. These switches emphasize scalability, speed, automation, and seamless integration into cloud-ready networks. Let’s break down the given options to determine which features are core attributes of this series.

Option A is a defining characteristic. The CloudEngine series is built with Software-Defined Networking (SDN) capabilities in mind. They are compatible with controllers such as Huawei’s Agile Controller and support SDN protocols like OpenFlow and NetConf. This allows dynamic provisioning, centralized policy enforcement, and agility in traffic management. SDN support enables greater control over network behavior, making it crucial for today’s virtualized environments.

Option B is not entirely accurate. Although Huawei offers FusionSphere as a cloud computing platform, and CloudEngine switches can be deployed within that environment, the switches do not possess native integration in the sense of embedded features specifically for FusionSphere. Instead, integration would typically occur at the orchestration layer. Therefore, this is not a defining trait of the switch series.

Option C is another key feature. CloudEngine switches leverage custom-built, high-performance ASICs (Application-Specific Integrated Circuits). These ASICs enable line-rate packet forwarding, large table capacities, and ultra-low latency. ASIC optimization is critical in environments requiring rapid data handling such as hyperscale data centers or high-performance computing networks. This hardware design is a hallmark of the CloudEngine’s engineering excellence.

Option D is incorrect. CloudEngine switches are not equipped with built-in WLAN controller functionality. That feature belongs to other product lines like the Huawei Agile Switches or standalone WLAN controllers (AC series). CloudEngine devices are intended primarily for aggregation, core, or spine-leaf architectures — not for wireless access layer tasks.

Option E is partially correct but lacks universality. While some high-end CloudEngine models may support MPLS (especially for carrier-grade or DCI roles), it is not a standard feature across the entire CloudEngine portfolio. Therefore, MPLS support is model-dependent and not a defining series-wide feature.

In summary, the two standout features that define Huawei’s CloudEngine switches are SDN architecture support and high-performance ASIC hardware, which contribute to the series’ reputation for agility, speed, and scalability in cloud environments.

Question 7:

In the context of Huawei's Agile Network architecture, which two of the following technologies play a key role in enhancing network resilience? (Select two options.)

A. MPLS Traffic Engineering (MPLS TE)
B. Virtual Routing and Forwarding (VRF)
C. Transparent Interconnection of Lots of Links (TRILL)
D. Link Aggregation using LACP
E. Spanning Tree Protocol (STP)

Correct Answers: C and D

Explanation:

Huawei’s Agile Network strategy focuses on building networks that are not only intelligent but also highly resilient to faults and link failures. To achieve this, the network incorporates technologies that minimize downtime, support fast convergence, and maintain traffic flow even in adverse conditions. Two of the technologies that align best with these goals are TRILL and Link Aggregation with LACP.

TRILL (Transparent Interconnection of Lots of Links) is an advanced technology that enhances traditional Layer 2 Ethernet networks by enabling all available paths to be active. Unlike the Spanning Tree Protocol (STP), which blocks redundant links to prevent loops, TRILL utilizes multiple paths concurrently. This results in improved bandwidth utilization and quicker convergence during topology changes, both of which are essential for network resilience. TRILL also introduces routing capabilities within Layer 2, which means data can be rerouted quickly in case of link failures—ensuring minimal disruption.

LACP (Link Aggregation Control Protocol), on the other hand, allows several physical interfaces to be bundled into a single logical link. This technology enhances fault tolerance by enabling traffic to continue flowing even when one or more physical links in the bundle fail. Moreover, LACP supports dynamic link addition and removal, automatic load balancing, and improved bandwidth utilization. Its ability to provide redundancy at the link level is critical for sustaining consistent network performance.

Let’s contrast these with the incorrect options:

• MPLS TE (Option A), though useful in service provider environments for traffic optimization and rerouting, is not a core part of Huawei’s enterprise-focused Agile Network for resilience.

• VRF (Option B) enhances network segmentation and supports multi-tenancy, but it doesn’t directly contribute to resilience or failover at the physical or logical link level.

• STP (Option E) was historically vital for loop prevention but is limited by its slow convergence. Modern networks favor technologies like TRILL, which offer greater speed and efficiency in maintaining uptime.

Thus, the most accurate answers that represent technologies enhancing resilience in Huawei’s Agile Network are C (TRILL) and D (LACP).

Question 8:

Which two features are supported by Huawei's eSight platform for effective management of network devices? (Select two options.)

A. Fault detection and real-time performance analysis
B. Real-time security breach detection through traffic inspection
C. Centralized configuration control and software deployment
D. Fully automated network-wide configuration backups
E. Direct firewall rule management and configuration

Correct Answers: A and C

Explanation:

Huawei’s eSight platform serves as an integrated network management solution that helps administrators monitor, configure, and optimize their ICT environments. It offers centralized control over routers, switches, servers, storage units, and virtual systems. Among the many tools included, two core features that stand out for network device management are fault detection/performance monitoring and configuration/software deployment capabilities.

Option A (Fault detection and performance monitoring) refers to eSight’s ability to monitor the operational status of network devices continuously. It tracks real-time data such as CPU load, memory consumption, link status, and traffic throughput. These metrics are crucial for maintaining network stability and efficiency. The platform uses threshold-based alerting, allowing administrators to identify and resolve issues—such as degraded link performance or device malfunctions—before they cause service outages. In addition, historical performance data helps with trend analysis and long-term planning.

Option C (Configuration management and software deployment) is another cornerstone of eSight’s capabilities. It enables IT teams to automate routine network tasks such as updating device configurations, pushing firmware, and applying patches. The platform supports both individual and bulk operations, making it efficient for managing large environments. This function ensures consistent device settings, reduces configuration errors, and streamlines change management processes—key factors in maintaining a secure and reliable network infrastructure.

Let’s now examine the incorrect choices:

• Option B (Real-time traffic analysis for security breaches) overstates eSight’s capabilities. While eSight can track network usage patterns, it is not designed as a full-fledged security analytics tool. Tasks like intrusion detection or deep packet inspection are better handled by specialized security platforms.

• Option D (Automatic backup of all network configurations) is misleading. Although backup features are available, they typically require manual scheduling and configuration. It is not a fully automatic, network-wide feature that functions without administrative setup.

• Option E (Integrated firewall configuration and management) is beyond eSight’s core scope. While limited integration with Huawei security devices might exist, comprehensive firewall policy control is handled more appropriately through dedicated security management systems.

In conclusion, Huawei eSight’s strongest contributions to network device management are through fault detection/performance monitoring (A) and configuration and software deployment (C).

Question 9:

In a complex enterprise network, a network engineer is configuring OSPF to ensure fast convergence and efficient routing updates. The network has several areas, including a large backbone (Area 0) and multiple NSSAs. The engineer wants to introduce an external route into the NSSA that should not be redistributed beyond the NSSA itself.

Which type of LSA should the engineer use to accomplish this?

A. Type 3 LSA
B. Type 5 LSA
C. Type 7 LSA
D. Type 1 LSA

Correct Answer: C

Explanation:

OSPF (Open Shortest Path First) is a widely used IGP that uses LSAs (Link-State Advertisements) to share routing information within and between areas. Each LSA type serves a distinct role in OSPF’s hierarchical design.

When dealing with Not-So-Stubby Areas (NSSAs), special handling of external routes is required. Normally, external routes (from another protocol like BGP or a static route) are injected into OSPF using Type 5 LSAs. However, Type 5 LSAs are not allowed within stub or NSSA areas.

To support external route injection in an NSSA, Type 7 LSAs are used. These LSAs are converted to Type 5 LSAs by the ABR (Area Border Router) when exiting the NSSA into the backbone (Area 0), unless the P-bit is not set. If the engineer’s intention is to prevent the external route from propagating beyond the NSSA, the P-bit (propagate bit) should be cleared. This ensures the route stays within the NSSA and is not advertised as a Type 5 LSA beyond the ABR.

By choosing Type 7 LSAs, the engineer ensures OSPF complies with area restrictions and supports NSSA flexibility. This approach is commonly used for scenarios like injecting local default routes in a branch office while preventing unnecessary advertisement to the rest of the OSPF domain.

Thus, the most suitable LSA for introducing an external route that should remain within an NSSA is the Type 7 LSA.

Question 10:

A Huawei router running BGP needs to establish peer connections with multiple internal routers in a large-scale enterprise network. To reduce the number of BGP sessions and improve scalability, what BGP feature should be configured?

A. Route Reflector
B. Confederation
C. Local Preference
D. AS-Path Prepending

Correct Answer: A

Explanation:

In large-scale BGP deployments—particularly within an iBGP (internal BGP) environment—establishing a full mesh of peerings among all routers becomes impractical as the network grows. The BGP full-mesh rule requires every iBGP router to peer with every other iBGP router to ensure routing information is fully shared, since iBGP does not re-advertise routes learned from one iBGP peer to another.

To address this scalability issue, BGP introduces the Route Reflector (RR) mechanism. A Route Reflector allows a central router (the RR) to receive BGP routes from client routers and reflect them to other clients, bypassing the full-mesh requirement. Non-client routers can also be configured, but only client-to-client advertisement through the RR is guaranteed.

Here’s how it works:

• RR clients establish iBGP sessions with the Route Reflector.

• When the RR receives a route from one client, it can reflect that route to other clients or non-clients.

• This dramatically reduces the number of required iBGP sessions.

This mechanism preserves the loop prevention features of BGP by using the Cluster ID and Originator ID attributes.

The other options are less applicable:

• B: Confederation is used for inter-domain segmentation but still requires sub-AS configuration.

• C: Local Preference is used for outbound path selection, not scalability.

• D: AS-Path Prepending manipulates route preferences between ASes, not session scalability.

Thus, in this context, using a Route Reflector (A) is the most appropriate solution for enhancing iBGP scalability.