H12-821_V1.0 Exam Dumps - HCIP-Datacom-Core Technology V1.0

Edge ports are used in RSTP to bypass the spanning tree calculation for ports connected to end devices. By configuring ports like SWD's GE0/0/2 and SWC's GE0/0/2 as edge ports, they transition directly to the Forwarding state upon activation, ensuring faster convergence. Statement A is incorrect because receiving BPDU invalidates the edge port status ​.

ï‚· OSPF Area Design and Loop Prevention:

OSPF uses a hierarchical structure with areas to improve scalability and efficiency. Area 0, the backbone area, plays a crucial role in ensuring loop-free route distribution between areas. The following mechanisms are key to preventing routing loops:

Strict adherence to hierarchical area design.

Prohibition of direct inter-area route exchanges between non-backbone areas.

HCIP-Datacom-Core Technology Training Material (OSPF Basics and Advanced Concepts)​​.

ï‚· Analysis of Each Statement:

A. Inter-area routes cannot be directly transmitted between non-backbone areas.This statement isTRUE. OSPF mandates that all inter-area routing must pass through Area 0. Direct inter-area route exchanges between two non-backbone areas are not allowed to prevent loops.

 R1 is a Level-1 router in Area 49.0001, while R4 is in Area 49.0004. Level-1 routers only maintain LSDBs for their own area and do not contain LSPs from other areas, such as R4’s LSP.

ï‚· R2 is a Level-1-2 router, so it maintains LSDBs for both Area 49.0001 (Level-1) and Level-2 domains, which include LSPs from R4.

ï‚· R3 and R4, as Level-2 routers, exchange LSPs with each other within the Level-2 domain.

 Thus, the LSDB of R1 does not include R4’s LSP ​.

BGP, IS-IS, and OSPF support the configuration of default routes through specific command configurations. For example, BGP uses thedefault-originatecommand, IS-IS uses adefault-route-advertisemethod, and OSPF can advertise default routes usingdefault-information originate. ICMP, however, is not a routing protocol and does not support this functionality ​.

A is false– The correct formula is: Skew_Time = (256 - Priority)/256 × Advertisement_Interval.

B is false– By default, thepreemption delayis typically0s, not 1s, meaning a higher-priority backup router can preempt immediately unless configured otherwise.

C is true– Thedefault Advertisement intervalin VRRP is2 seconds.

D is true– The formula Master_Down_Interval = 3 × Advertisement_Interval + Skew_Time is correct.

Reference from Huawei HCIP-Datacom-Core Technology Study Guide:

“The VRRP Skew_Time is calculated as (256 - Priority)/256 × Adver_Interval. The Master_Down interval includes this Skew_Time to stagger failover.”

(Chapter: High Availability – Section: VRRP Timer Mechanism)

Comprehensive and Detailed Step-by-Step Explanation:

1. What is NETCONF?

NETCONF (Network Configuration Protocol) is an XML-based protocol used for network device configuration and management.

It enables reading, modifying, deleting, and restoring configurations programmatically.

2. Supported Operations:

Option A: Modifying configurations

Correct.

NETCONF allows you to modify existing configurations on network devices.

Option B: Deleting configurations

Correct.

Configurations can be deleted using NETCONF operations.

Option C: Restoring configurations

Correct.

NETCONF can restore configurations by applying previously saved configuration data.

Option D: Backing up configurations

Correct.

NETCONF can retrieve and save the current configuration as a backup.

3. Summary:

NETCONF supports all listed operations: modifying, deleting, restoring, and backing up configurations.

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 ​.

Comprehensive and Detailed Step-by-Step Explanation:

1. What is the BFD Echo Function?

BFD (Bidirectional Forwarding Detection) is used to detect link failures.

TheEcho functionis an optional feature that tests link connectivity by looping back packets sent from the local device through the forwarding path.

2. Analysis of Each Statement:

Option A: If URPF is enabled on the peer end, BFD packets may be incorrectly discarded on the peer end.

Correct.

URPF (Unicast Reverse Path Forwarding) checks whether the source IP address of an incoming packet is reachable via the interface it was received on. Since the Echo function uses loopback packets, this can conflict with URPF, causing the packets to be dropped.

Option B: In the BFD Echo function, the device uses the IP address of the outbound interface as the source IP address by default.

Correct.

By default, the outbound interface's IP address is used as the source address for BFD Echo packets.

Option C: The BFD Echo function applies only to single-hop BFD sessions.

Incorrect.

The BFD Echo function can be used for both single-hop and multi-hop BFD sessions.

Option D: When configuring a BFD session supporting the BFD Echo function, you need to configure both the local and remote discriminators.

Incorrect.

The BFD Echo function is locally configured and does not require setting remote discriminators. The function operates independently of the remote device's configuration.

3. Summary:

The correct statements areAandB.