H12-821_V1.0 exam questions for practice in 2025 Updated 176 Questions [Q14-Q29]

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H12-821_V1.0 exam questions for practice in 2025 Updated 176 Questions

Updated Apr-2025 Premium H12-821_V1.0 Exam Engine pdf – Download Free Updated 176 Questions

質問14
On an OSPF network, one router with P2P as the network type is directly connected to another router with P2MP as the network type. If the Hello intervals on the two routers are changed to be the same, neighbor relationship establishment and LSDB synchronization are not affected.

真

偽

The scenario describes a mismatch in OSPF network types between two connected routers: one set to Point-to- Point (P2P) and the other set to Point-to-Multipoint (P2MP). While aligning Hello intervals may seem sufficient for establishing an OSPF neighbor relationship, the fundamental mismatch in network types introduces issues.
* OSPF Network Types
* P2P: Assumes a direct connection with a single neighbor, uses faster convergence and simpler LSDB synchronization.
* P2MP: Supports multiple neighbors on a single interface, requiring different handling for DR
/BDR roles and LSDB updates.
* Impact of Network Type Mismatch
* If Hello intervals are aligned, adjacency establishment might occur. However, mismatched network types affect neighbor role assignment and LSDB synchronization.
* P2P expects a direct link and would handle updates differently than P2MP, which assumes multiple neighbors. This leads to inconsistencies in route calculation and forwarding.
* HCIP-Datacom-Core Reference
* OSPF Basics and Configurationclearly outlines the criticality of consistent network type configuration for stable OSPF operation.
* Lab examples in the HCIP Datacom Lab Guidefurther demonstrate the consequences of such mismatches, including unstable neighbor states and incomplete LSDB synchronization.
Hence, the statement that neighbor relationships and LSDB synchronization remain unaffected is incorrect.
Proper OSPF operation requires matching network types in addition to aligned Hello intervals.

質問15
Which of the following statements regarding Local-Preference in BGP is true?

Local-Preference affects traffic that enters an AS.

Local-Preference can be transmitted between ASs.

The default Local-Preference value is 100.

Local-Preference is a well-known mandatory attribute.

The Local-Preference attribute is used within an AS to influence outbound traffic paths. The default value is
100, and it is a well-known discretionary attribute, meaning it is not mandatory and does not travel across AS boundaries .

質問16
Which of the following statements regarding BGP route advertisement are false?

All the BGP routes learned from all BGP peer will be advertised to other BGP peers.

Only the optimal routes preferred by BGP can be advertised to other BGP peers.

By default, the routes learned from an IBGP peer will not be forwarded to other IBGP peers.

Only the routes learned from IGPs can be advertised to other BGP peers.

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

質問17
Which of the following statements regarding OSPF is true?

OSPF does not have an acknowledgement mechanism. Therefore, OSPF relies on the upper-layer protocol, TCP, for acknowledgement.

OSPF performs LSDB update every 30 minutes.

OSPF uses the Bellman-Ford algorithm, and each router independently runs this algorithm.

OSPF floods a LSU packet at an interval of 5s.

OSPF routers refresh and flood LSAs in the Link-State Database (LSDB) every 30 minutes by default to maintain topology consistency. OSPF does not rely on TCP; it uses its own acknowledgment mechanism. It also uses the Dijkstra algorithm, not Bellman-Ford. The flooding interval for LSU packets is shorter, typically
5 seconds .

質問18
As shown in the following figure, a new AP is deployed In dual link MSB networking (load balancing mode).
Which AC will the connect to?

AC1

Random access

なし

AC2

質問19
Which three transmission modes are supported for IPv4 packets?

Anycast

Broadcast

Unicast

Multicast

IPv4 supports three main transmission modes:
* Unicast: One-to-one communication.
* Broadcast: One-to-all communication within a network.
* Multicast: One-to-many communication to a group of interested receivers.Anycast is not a native IPv4 mode but is introduced in IPv6 .

質問20
Which of the following statements regarding DR/BDR are false?

In a broadcast network, DR and BDR must be elected. A broadcast network without a DR or BDR cannot operate normally.

DR others listen on the multicast address 224.0.0.5.

All DR others establish neighbor relationships with DR and BDR only.

DR others listen on the network address 224.0.0.6.

In OSPF, DR and BDR listen on the multicast address 224.0.0.6, while all OSPF routers (including DR others) listen on 224.0.0.5. DR others establish neighbor relationships with DR and BDR, but they do not listen on 224.0.0.6. This makes Option D incorrect, as only DR and BDR use 224.0.0.6 .

質問21
On an STP network, the root bridge, root port, and designated port are elected in sequence. The election rules of these ports are different. List the steps for electing the root port in sequence.

説明する：
The sequence of steps for electing the root port in an STP (Spanning Tree Protocol) network is as follows:
* Bridge ID Comparison: The Bridge ID (BID) is compared between the bridges in the network. A smaller value indicates a higher priority, meaning the bridge with the lowest Bridge ID is elected as the root bridge.
* RPC (Root Path Cost) Comparison: The path cost to reach the root bridge is calculated. The router with the lowest Root Path Cost (RPC) to the root bridge will have a higher priority for the election of the root port.
* Peer BID Comparison: If there is a tie in the Root Path Cost, the Peer BID is compared. A smaller Peer BID indicates a higher priority. This step ensures that if two routers have the same RPC, the one with the lower Peer Bridge ID wins.
* Local BID Comparison: If there is still a tie, the Local BID is compared. A smaller Local BID indicates a higher priority. This final step ensures that the router with the lowest local identifier is selected.
* Bridge ID Comparison:The first step in electing the root port is comparing the Bridge IDs. The bridge with the lowest Bridge ID becomes the root bridge. The Bridge ID is made up of the bridge priority and MAC address. The root bridge is the center of the network for STP, and all other ports will calculate their paths based on this root.

質問22
Which of the following statements regarding OSPF route summarization commands are true?

The asbr-summary command is executed in the OSPF view.

The abr-summary command is executed in the OSPF area view.

Advertise is the default parameter of the abr-summary command. That is, if not-advertise is not specified in the abr-summary command, the advertise parameter takes effect by default.

Not-advertise is the default parameter of the abr-summary command. That is, if advertise is not specified in the abr-summary command, the not-advertise parameter takes effect by default.

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

質問23
Which of the following TLVs is used by ISIS to describe the IP address of an interface?

129

131

128

132

In the IS-IS protocol, TLV 129 (IPv4 interface address) is used to describe the IP address of an interface.
Each TLV type carries specific information, and TLV 129 specifically relates to interface IP addresses .

質問24
Match the following IPv4 multicast protocols with the corresponding functions.

説明する：
IGMP: Manages IPv4 multicast group members and runs on the multicast network’s last segment (that is, the network segment where a Layer 3 network device is connected to user hosts).
PIM: Sends multicast data over the network to the multicast device that is connected to group members that have requested the multicast data, implementing multicast data forwarding based on routes.
IGMP Snooping: Manages and controls the forwarding of multicast data packets to effectively suppress the flooding of multicast data packets on the Layer 2 network.
IGMP (Internet Group Management Protocol):
* IGMP is used by hosts and adjacent multicast routers to establish and maintain multicast group memberships on a local subnet.
* It allows a host to inform a multicast router of its desire to receive multicast traffic for a specific group.
* It operates at Layer 3 and runs on the last segment of the network.

質問25
Which of the following statements about multicast packet forwarding is true?

If a multicast data packet fails the RPF check, the packet must have been received through a sub-optimal interface. However, this interface still receives and forwards the multicast traffic downstream.

IGMP snooping cannot control the scope of multicast traffic flooding on a Layer 2 network.

The source address of a multicast packet is a unicast address.

In multicast transmission, the destination address of a packet can be the unicast address of a host.

質問26
An IP prefix list is a common matching tool used in routing policies. Which of the following cannot be configured as matching conditions in an IP prefix list on a Huawei router?

Port number

Mask

アクション

インデックス

IP Prefix List Matching Conditions
* An IP prefix list matches based on:
* Mask: Specifies the subnet mask length.
* Action: Specifies whether to permit or deny.
* Index: Orders the rules within the prefix list.
* Port numbers are not applicable as matching conditions in an IP prefix list.
HCIP-Datacom-Core Reference
* IP prefix list configurations are detailed in the routing policy and route filtering chapters.

質問27
A switch runs MSTP. The configuration is shown in the figure. What is the role of this switch in MSTI 1?

Uncertain

Root switch

Non-root switch

Secondary root switch

Based on the MSTP configuration shown, the role of the switch in MSTI 1 cannot be determined without additional details about the topology or priority values of other switches in the instance. The role could be a root switch, secondary root, or non-root, depending on these factors .

質問28
There are various types of VPNs, which can be applied to different layers. Which of the following network layers does SSL VPN belong to?

Network layer

Application layer

Transport layer

Data link layer

SSL VPN and Its Functionality:
* SSL VPN (Secure Sockets Layer Virtual Private Network) provides secure remote access to a network using SSL/TLS protocols.
* SSL VPN operates at the Application Layer of the OSI model. It enables secure communication for applications like web browsers, email clients, and file sharing.
* Unlike IPsec VPN, which operates at the Network Layer, SSL VPN focuses on application-specific encryption and authentication.

質問29
Which of the following statements about multicast packet forwarding is true?

If a multicast data packet fails the RPF check, the packet must have been received through a sub- optimal interface. However, this interface still receives and forwards the multicast traffic downstream.

IGMP snooping cannot control the scope of multicast traffic flooding on a Layer 2 network.

The source address of a multicast packet is a unicast address.

In multicast transmission, the destination address of a packet can be the unicast address of a host.

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

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