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

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 be at least 26 bits .

If the less-equal parameter is not explicitly defined, the default value is 32 , 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 is 26 .

less-equal-value : Specifies the maximum mask length. Since it is not explicitly configured, the default value is 32 .

3. Summary:

greater-equal-value = 26

less-equal-value = 32

Comprehensive and Detailed In-Depth Explanation:

IP Multicast vs. Broadcast:

A. TRUE → Unlike broadcast , which sends data to all hosts in a subnet, multicast only sends data to interested receivers , preventing flooding .

B. TRUE → Multicast optimizes bandwidth usage by sending a single copy of data , which is then replicated at network routers only when necessary .

IP Multicast vs. Unicast:

C. FALSE → Multicast does not improve security ; it may expose data to unintended receivers if not properly controlled .

D. FALSE → Multicast reduces the load on the source because a single data stream serves multiple receivers instead of sending individual unicast streams .

📖 Reference: Huawei HCIA-Datacom Study Guide, IP Multicast Principles and Benefits.

An IP prefix filter is designed to match both the IP address and its prefix length, making it suitable for filtering routing information rather than data packets. Options A and D are incorrect because IP prefix filters do not work directly on data packets, and they can match both prefix numbers and lengths ​.

Policy-Based Routing (PBR) on interfaces is used to forward traffic based on specific policies rather than the routing table. However, PBR is not suitable for modifying the next-hop of locally originated traffic. Other scenarios listed are typical use cases for interface PBR ​.

When the level of an IS-IS interface is changed, the adjacency must be re-established because IS-IS adjacencies are formed based on matching levels (Level-1, Level-2, or both). Other changes, such as cost or hello intervals, do not disrupt the existing adjacency but might impact routing metrics or timing ​.