Free Huawei H12-821_V1.0 Practice Exam with Questions & Answers

Comprehensive and Detailed In-Depth Explanation:

OSPF-to-BGP route redistributiondoesnot allow modification of MED valuesdirectly using aroute-policyin Huawei devices.

Instead,MED can be set using a BGP attribute policy, not through the import command.

All other options (B, C, D) are correct:

B→ Route-policycan filter imported direct routes.

C→ network commanddoes not modify attributes, only announces existing routes.

D→ peer commandcan set Local Preferencevia route-policy.

????Reference:Huawei HCIA-Datacom Study Guide, BGP Route Policy and Attribute Modification.

Comprehensive and Detailed Step-by-Step Explanation:

Definition of the Origin Attribute:

The Origin attribute is a well-known mandatory attribute used to indicate the source of a route. It has three possible values:

i (IGP):The route was injected into BGP using the network command.

e (EGP):The route was learned from an EGP protocol (not commonly used now).

? (Incomplete):The route was redistributed into BGP from another routing protocol.

Analysis of Each Option:

Option A:Correct. When the network command is used, the Origin is set toi (IGP).

Option B:Incorrect. Routes learned from EGP have the Origin attribute set toe (EGP), not? (Incomplete).

Option C:Correct. BGP prefers routes with the Origin attribute in the order:IGP > EGP > Incomplete.

Option D:Correct. The Origin attribute is a well-known mandatory attribute.

DIS Election in IS-IS:

In IS-IS, theDesignated Intermediate System (DIS)is elected on broadcast networks to reduce the number of LSAs exchanged and maintain the LSDB.

The DIS is elected based onpriority:

The router with thehighest priorityis elected as the DIS.

If priorities are equal, theSystem IDis used as a tie-breaker, and the router with thehighest System IDbecomes the DIS.

HCIP-Datacom-Core Technology Training Material (IS-IS DIS Election Mechanism)​​.

Given DIS Priorities:

R1: Priority = 10

R2: Priority = 20

R3: Priority = 30

R4: Priority = 40

R4 has the highest DIS priority of 40, which makes it the clear choice for DIS election.

Scenario Details:

Since all devices are started simultaneously, the DIS election process will follow the priorities without requiring a tie-breaker (System ID).

Conclusion:

The device with the highest DIS priority isR4, and it will be elected as the DIS.

 Edge Port Behavior

An edge port transitions directly to the Forwarding state but reverts to participating in RSTP calculations if it receives a valid configuration BPDU. Thus, statement C is false.

 HCIP-Datacom-Core Reference

The behavior of edge ports and their transitions are discussed in the RSTP enhancement sections​​.

According to BGP route selection rules, a higherLocal_Prefvalue indicates a more preferred route. This rule is used to influence traffic flow within an autonomous system (AS), giving preference to routes with a higherLocal_Preffor outgoing traffic ​.

 BGP Open Message Components

The Open message contains the following critical parameters:

Local AS Number: The autonomous system of the router.

Router ID: A unique identifier for the router.

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

 Incorrect Option

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

 HCIP-Datacom-Core Reference

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

 Understanding Router ID and Its Role in OSPF:

In OSPF, the Router ID uniquely identifies a router within the OSPF domain. If two routers are configured with the same Router ID, it can lead to issues such as LSA conflicts and flapping. This is because the Router ID is used as a key in OSPF operations, including LSA generation and database synchronization.

HCIP-Datacom-Core Technology Training Material (OSPF Basics - Router ID and LSA Handling)​.

 Scenario Details:

Different Areas: Even if the two routers belong to different areas, the Router ID remains globally significant in the OSPF domain. This means that any duplication of Router IDs will confuse OSPF mechanisms.

ASBR (Autonomous System Boundary Router): When one of the routers is an ASBR, it generates Type 4 and Type 5 LSAs to describe external routes. These LSAs use the Router ID asan identifier. If another router in the network has the same Router ID, conflicts occur during LSDB synchronization.

Comprehensive and Detailed in-depth Step-by-Step Explanation:

To establish an OSPF neighbor relationship, the following conditions must be met:

The routers must share a common network segment.

Their Hello and Dead intervals must match.

Their OSPF network types must be compatible.

The IP subnet masks must match.

If two OSPF routers are ondifferent network segmentsand havedifferent subnet masks, one solution is to change the OSPFnetwork typetoPoint-to-Point (P2P)on both interfaces.

Point-to-Point (P2P):

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

This is ideal for directly connected links between two routers.

NBMA (Non-Broadcast Multi-Access):

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

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

P2MP (Point-to-Multipoint):

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

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

Broadcast:

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

Therefore, the correct answer isA. Point-to-point.

Secure access channels include protocols that encrypt the transmitted data to protect against interception or unauthorized access. HTTPS (HyperText Transfer Protocol Secure) ensures data encryption over web communications, while SFTP (Secure File Transfer Protocol) provides secure file transfer by utilizing SSH for data encryption. Telnet and SNMPv2, on the other hand, lack robust encryption and are considered insecure. Huawei security standards highlight the importance of encrypted communication to prevent data leaks ​.

When a Huawei firewall receives a packet that does not match any existing session table entry, it discards the packet. This is part of the default firewall policy, which ensures that unrecognized traffic is treated as a potential security risk and blocked. This behavior is vital for preventing unauthorized access and mitigating external attacks. The feature aligns with Huawei's default security strategies as detailed in their firewall operation manuals ​.