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

Comprehensive and Detailed Step-by-Step Explanation:

1. IPv6 and Neighbor Discovery Protocol (NDP):

In IPv4, a host uses ARP (Address Resolution Protocol) to map an IP address to a MAC address for communication.

In IPv6, ARP is not used. Instead, IPv6 uses the Neighbor Discovery Protocol (NDP) for address resolution.

2. Why the Statement is FALSE:

IPv6 does not use ARP for resolving link-layer addresses.

IPv6 uses NDP, which operates through ICMPv6 messages to perform the equivalent function.

3. Summary:

The statement is FALSE because IPv6 uses NDP, not ARP, to obtain the link-layer address of the destination 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 ​.

Comprehensive and Detailed Step-by-Step Explanation:

ACL Capabilities:

ACLs are versatile tools that can match:

Data packets: Using IP addresses, protocols, ports, etc.

Routes: ACLs can be used in route filtering, matching both IP prefix length and mask length.

Correct Statement:

ACLs can match both the IP address prefix length and mask length in route filtering applications.

References:

HCIA-Datacom Study Guide, Chapter: ACL Applications

Huawei Route Filtering Using ACLs

Comprehensive and Detailed Step-by-Step Explanation:

1. Overview of BGP:

BGP (Border Gateway Protocol) is an Exterior Gateway Protocol (EGP) designed to exchange routing information between different Autonomous Systems (ASs) on the internet. Unlike traditional distance-vector protocols (like RIP), BGP is considered a path-vector protocol, as it not only determines reachability but also ensures policy-based routing decisions and advanced path selection mechanisms.

2. Analysis of Each Option:

Option A: BGP does not support authentication. Therefore, it cannot ensure network security.

This statement is incorrect.

BGP supports authentication using mechanisms such as TCP MD5 (Message Digest 5) and TCP-AO (Authentication Option). These authentication mechanisms ensure that BGP messages are not tampered with or intercepted during transmission, enhancing network security.

 MQC and PBR

MQC (Modular QoS Command-Line Interface): Applied to interfaces for classifying and controlling traffic.

PBR (Policy-Based Routing): Used to influence packet forwarding based on policies rather than traditional routing tables.

Both MQC and PBR can be configured on device interfaces to filter incoming/outgoing packets or control their forwarding paths.

 HCIP-Datacom-Core Reference

The use of MQC and PBR on device interfaces is elaborated in the QoS and routing control chapters​​.

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 to i (IGP).

Option B: Incorrect. Routes learned from EGP have the Origin attribute set to e (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.

References:

HCIA-Datacom Study Guide, Chapter: BGP Attributes

Huawei BGP Attribute Comparison

Mandatory BGP Attributes

Next_Hop: Specifies the next hop to reach the destination.

AS_Path: Lists the autonomous systems traversed, crucial for loop prevention and route selection.

Optional Attributes

MED (Multi-Exit Discriminator) and Local_Preference are optional attributes that aid in route preference but are not mandatory.

HCIP-Datacom-Core Reference

BGP attribute behavior and classifications are detailed in BGP path selection principles​​.

 Link fault alarm

 The BFD session goes down.

 Interrupted OSPF neighbor relationship

In inter-AC roaming scenarios, an AC (Access Controller) can serve as the mobility server for multiple mobility groups, enabling it to manage roaming among multiple groups. However, an AC can only belong to one specific mobility group. This constraint ensures that mobility management remains streamlined and avoids conflicts. Huawei WLAN mobility configuration guides validate this setup ​.

Router LSAs (Type 1) and Network LSAs (Type 2) are advertised only within a single OSPF area, as they describe the topology within the area. In contrast, Summary LSAs (Type 3) and AS External LSAs (Type 5) are used for inter-area and external routing, respectively ​.