H12-821_V1.0 Exam Dumps - Huawei HCIP-Datacom Questions and Answers

A is false– Thedefault value of Local_Pref is 100, not 0.

B is false–Local_Pref is not advertised to EBGP peers, it is only sent toIBGP peers.

C is correct– TheLocal_Pref value stays constantunless modified by a route-policy or filter.

D is correct–Higher Local_Pref values indicate preferred paths, so BGP prefers the path with the highest Local_Pref among multiple options.

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

“Local_Pref is used to select the best outbound path for traffic leaving the AS. It is only shared among IBGP peers and defaults to 100. The higher the value, the more preferred the route.”

(Chapter: BGP Path Attributes – Section: Local Preference)

In IS-IS:

Level-1 routerscan only form neighbor relationships with other Level-1 routersin the same area.

Level-2 routerscan form neighbor relationships with other Level-2 routersregardless of area ID.

Level-1-2 routerscan form relationships at both levels depending on the peer's configuration.

So, iftwo Level-1 routershavedifferent area addresses, theycannotestablish a neighbor relationship.

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

“Level-1 routers must have the same area address to establish neighbor relationships. Level-2 routers can peer across different areas.”

(Chapter: IS-IS Protocol Principles – Section: Neighbor Establishment)

IGMP Version Mismatch

If the IGMP snooping version on the device is earlier than the IGMP version on user hosts, the device may fail to parse IGMP Report messages correctly. As a result, the device forwards these messages only to router ports without generating group member ports or forwarding entries.

Consequently, users cannot receive multicast data.

HCIP-Datacom-Core Reference

Multicast and IGMP snooping behaviors under mismatched conditions are described in the multicast configuration chapters​​.

Comprehensive and Detailed Step-by-Step Explanation:

Bidirectional Forwarding Detection (BFD):

BFD is a lightweight protocol that provides rapid fault detection on links independent of the underlying routing protocol or media.

Requirements for BFD:

Both devices at the endpoints of the link must support and configure BFD for it to operate.

If one device does not support BFD, the feature cannot be used for link detection.

1. Understanding Prefix List Configuration:

The command ip ip-prefix huawei index 10 permit 10.1.1.0 24 greater-equal 26 defines a prefix filter:

The base prefix is 10.1.1.0/24.

The greater-equal 26 condition specifies that the mask length of matching prefixes must beat least 26 bits.

If the less-equal parameter is not explicitly defined, the default value is32, meaning the longest possible mask length for IPv4.

2. Explanation of Values:

greater-equal-value: Specifies the minimum mask length. In this case, the value is26.

less-equal-value: Specifies the maximum mask length. Since it is not explicitly configured, the default value is32.

3. Summary:

greater-equal-value = 26

less-equal-value = 32

Huawei HCIA-Datacom Study Guide, Chapter "IP Prefix List Configuration."

The prefix list permits the prefix1.1.1.1/24with a mask length greater than or equal to/26and less than or equal to/32. This means only prefixes with the base1.1.1.1and mask lengths between/26and/32will be permitted. Routes like1.1.1.2/16and1.1.1.1/24do not meet the mask length criteria, so they will be denied. Conversely, routes like1.1.1.1/26and1.1.1.1/32satisfy the condition and will be permitted ​.

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 ​.

A is correct– Local attack defense can classify and prioritize packets (e.g., OSPF, BGP, SSH) andensure critical protocols are processed firstby the CPU.

B is correct– Thedynamic link protection functionensures session-based applications (like SSH)are not disruptedeven during a CPU attack.

C is false– Different protocols havedifferent importance levels, soindividual rate limitsshould be configured, not a uniform one.

D is correct– CPU protectionalso applies to management interfaces, such as those used for Telnet, SSH, or SNMP.

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

“Devices support local attack defense by classifying packets, setting priorities, and limiting rates to protect CPU resources. These policies also apply to the management interface.”

(Chapter: Network Security – Section: Local Attack Defense)