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

The default sending interval for BFD (Bidirectional Forwarding Detection) control packets is 100 milliseconds. This interval ensures rapid detection of link faults, providing fast failover and minimizing downtime in network operations ​.

When STP and RSTP coexist in a network, RSTP switches will downgrade their operation to STP to ensure compatibility. However, this disables RSTP's rapid convergence features, as the protocol behaves like STP to maintain interoperability ​.

Comprehensive and Detailed In-Depth Explanation:

OSPF network typesaffect how protocol packets (Hello, LSA updates) are transmitted:

NBMA (Non-Broadcast Multi-Access)networks (e.g., Frame Relay) donot support multicast, so routers mustunicastOSPF packets to neighbors.

Broadcast networks(e.g., Ethernet) supportmulticastand use224.0.0.5 for Hello packetsand224.0.0.6 for DR/BDR communication.

The statement isfalsebecause:

NBMA does not unicast all packets—only Hello packets must bemanually configuredto be unicast.

LSAs and routing updates can still be multicastif an NBMA network is configured aspoint-to-multipoint.

????Reference:Huawei HCIA-Datacom Study Guide, OSPF Network Types and Packet Transmission.

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

To understand this question, let's first review the functional planes in network devices, particularly Huawei switches:

Control Plane:

The control plane is responsible for generating and maintaining routing tables and forwarding entries.

It uses protocols like OSPF, BGP, and RIP to exchange routing information with other network devices. Once the routing information is processed, it installs forwarding entries into the forwarding plane for actual packet forwarding.

On Huawei switches, the control plane is mandatory for building and updating the forwarding table. Without it, the data plane cannot forward traffic correctly.

Forwarding Plane (or Data Plane):

This plane handles the actual forwarding of packets based on the forwarding table created by the control plane.

The forwarding plane operates at high speed to ensure that traffic flows efficiently.

Monitoring Plane:

This plane is responsible for network management and monitoring. It gathers statistics and provides tools for troubleshooting and visibility.

In this case,the control plane provides the routing information and forwarding entries required for the data plane to perform packet forwarding.Therefore, the correct answer isB. Control plane.

Comprehensive and Detailed Step-by-Step Explanation:

1. Understanding the IGMP Group Entry:

The IGMP group entry contains key information about multicast groups on the interface:

Group Address (225.1.1.2):The multicast group address that the user has joined.

Last Reporter (10.1.6.10):The IP address of the last host that sent an IGMP Report message for this group.

Uptime:The duration since the group was first reported.

Expires:The remaining time before the group entry ages out if no further reports are received.

2. Analysis of Each Statement:

Option A: This entry can be used to construct the corresponding (S, G) entry.

Incorrect.

This is a group entry for IGMP, which contains information about the group (G) but does not include a specific source (S). (S, G) entries are created in PIM (Protocol Independent Multicast), not IGMP.

Option B: This entry is created when the device receives an IGMP Join message from a user.

Correct.

IGMP Join messages are used by hosts to signal their intent to join a multicast group. When such a message is received, the group entry is created.

Option C: Expires indicates the aging time of the IGMP group.

Correct.

The "Expires" field shows the remaining time before the group entry ages out if no further IGMP reports are received.

Option D: 225.1.1.2 is the address of the group that the user joins.

Correct.

The "Group Address" field explicitly states that 225.1.1.2 is the multicast group that the user has joined.

3. Summary:

Correct Options:B, C, D

In Layer 3 roaming scenarios, STAs (stations) remain on different subnets before and after roaming. To ensure that user traffic reaches the original subnet, it must be tunneled back over a CAPWAP tunnel. This technique prevents disruptions in communication and enables seamless roaming. Huawei’s Layer 3 roaming design guidelines emphasize the use of CAPWAP tunnels for user traffic forwarding ​.

 Neighbor Discovery Protocol (NDP):

NDP is a key protocol in the IPv6 protocol suite, replacing ARP (Address Resolution Protocol) in IPv4.

It operates using ICMPv6 (Internet Control Message Protocol for IPv6) and is critical for managing interactions between IPv6 nodes on the same link.

HCIP-Datacom-Core Technology Training Material (NDP Functions and Features)​​.

 NDP Features and Functions:

A. Address resolution:NDP resolves IPv6 addresses into MAC addresses, similar to ARP in IPv4. It uses Neighbor Solicitation (NS) and Neighbor Advertisement (NA) messages for this purpose.Reference:HCIP-Datacom-Core Technology Training Material (Address Resolution in IPv6)​.

B. Neighbor state tracing:NDP tracks the state of neighbors to determine their reachability. It maintains a neighbor cache and uses NS/NA messages to verify whether neighbors are reachable.Reference:HCIP-Datacom-Core Technology Training Material (Neighbor Reachability in IPv6)​.

C. Duplicate address detection (DAD):NDP ensures that IPv6 addresses are unique within a network. Before assigning an address to an interface, DAD is used to verify that no other node is using the same address. This is done via NS messages.Reference:HCIP-Datacom-Core Technology Training Material (IPv6 Address Assignment and DAD)​.

D. Redirection:NDP provides redirection functionality to inform hosts of a better first-hop router for reaching a particular destination. It uses ICMPv6 Redirect messages for this purpose.Reference:HCIP-Datacom-Core Technology Training Material (NDP Redirect Functionality)​.

 Conclusion:NDP supports all the mentioned functions and features:Address resolution,Neighbor state tracing,Duplicate address detection, andRedirection, making it indispensable for IPv6 networks.

Theasbr-summarycommand is executed in the global OSPF view to summarize external routes. Theabr-summarycommand is executed in the OSPF area view to summarize routes between areas. By default, theadvertiseparameter is enabled unless explicitly overridden by thenot-advertiseoption ​.

Comprehensive and Detailed Step-by-Step Explanation:

Default OSPF Hello Timer:

The OSPF Hello timer is used to send periodic Hello packets and maintain neighbor relationships.

Default Hello timers:

Broadcast and P2P:10 seconds

NBMA and P2MP:30 seconds

Network Types Using 30s Hello Time:

P2MP (C):OSPF sends Hello packets every 30 seconds by default.

NBMA (D):OSPF also uses 30 seconds for NBMA networks.

To compress the IPv6 address 2001:0DB8:0000:C030:0000:0000:09A0, the following rules are applied:

Remove leading zeros in each hextet (e.g., 0DB8 becomes DB8).

Replace contiguous blocks of zeros with :: (only once in the address).Thus, the compressed form is 2001:DB8:0:C030::9A0 ​.