Free Huawei H12-821_V1.0 Practice Exam with Questions & Answers | Set: 7

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.

Comprehensive and Detailed Step-by-Step Explanation:

1. Understanding IGMP (Internet Group Management Protocol):

IGMP is used in multicast networking to manage membership of devices in multicast groups.

Key parameters in the configuration provided:

Interface IP Address:192.168.1.1

IGMP Version:2

Query Interval (Configured):60 seconds

Maximum Query Response Time:10 seconds

Querier Address:192.168.1.1

2. Analysis of Each Statement:

Option A: The IP address of the interface is 192.168.1.1.

Correct (True Statement).

The configuration clearly shows that the IP address of the interface is 192.168.1.1.

Option B: The maximum response time to Query messages is 10s.

Correct (True Statement).

The configuration explicitly mentions: Value of maximum query response time for IGMP: 10 s.

Option C: The interval for sending Group-Specific Query messages is 60s.

Incorrect (False Statement).

The 60-second value refers to thequery interval, which is the time interval betweengeneral queriessent by the querier.

The interval forgroup-specific queriesis not specified in this configuration. It is determined dynamically based on the multicast environment and is usually shorter than the general query interval.

Option D: The IGMP version is IGMPv2.

Correct (True Statement).

The configuration specifies: Current IGMP version is 2.

3. Why Option C is False:

The 60-second value is forgeneral query interval, not group-specific query interval.

The statement misinterprets the configuration, making itfalse.

4. Summary:

Correct Answer:C (The interval for sending Group-Specific Query messages is 60s).

In dual-link MSB networking with load balancing, the new AP will connect to the AC with the lower number of connected APs. In this case, AC2 has only 20 connected APs, while AC1 has 100. Therefore, the new AP will connect to AC2 ​.

Comprehensive and Detailed Step-by-Step Explanation:

Blackhole Route Issue in BGP:

In IBGP, the next hop of a route learned from an EBGP peer is not changed by default. If an IBGP peer cannot reach the next hop, blackhole routes may occur.

To prevent this, thepeer next-hop-localcommand is used to set the next hop to the local router's IP address.

Other Commands:

peer mpls-local-ifnet:Used in MPLS networks to set the next hop as the local interface address.

peer private-nexthop:Allows advertising private IP addresses as the next hop.

peer next-hop-invariable:Ensures the next hop is not modified during route advertisement, which is the opposite of what is required here.

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 ​.

 LSA Lifetime and Deletion

The LS Age field in the LSA header tracks the age of an LSA. When the LS Age reaches its maximum value (3600 seconds), the LSA is marked for deletion. This ensures old or stale LSAs are removed from the network to maintain accurate routing information.

 HCIP-Datacom-Core Reference

Detailed explanation of LS Age behavior and LSA deletion processes can be found in the OSPF LSDB and LSA sections​​.

Comprehensive and Detailed Step-by-Step Explanation:

Interface ID in IPv6:

Theinterface IDis the last 64 bits of an IPv6 address, and it uniquely identifies an interface within a subnet.

It can be generated in three ways:

Manually Configured:Explicitly assigned by an administrator.

System-Generated:The operating system assigns a random or pseudo-random value.

EUI-64 Standard:Generated based on the MAC address of the interface.

Correct Statement:

IPv6 supports all three methods for generating interface IDs.

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

In OSPF,Link State Advertisements (LSAs)are used to exchange routing and topology information. Each LSA in the OSPF network is uniquely identified using a3-tuple identifier, which consists of:

Link State ID:

The Link State ID uniquely identifies the LSA within the OSPF area. Its value depends on the LSA type. For example, for a Router LSA, the Link State ID is the originating router’s Router ID.

Advertising Router:

This is the Router ID of the router that generated the LSA. It identifies which router is responsible for creating and advertising this LSA.

LSType:

This field identifies the type of LSA (e.g., Router LSA, Network LSA, Summary LSA, AS-External LSA, etc.). It is crucial for interpreting the purpose and content of the LSA.

TheLS Sequence Numberis not part of the 3-tuple that uniquely identifies the LSA. Instead, it is used to determine the most recent version of the LSA in case there are multiple instances of the same LSA.

ICMPv6 messages are classified into two types: error messages (e.g., Destination Unreachable, Time Exceeded) and informational messages (e.g., Echo Request, Echo Reply). This classification is fundamental to ICMPv6's operation ​.

Comprehensive and Detailed In-Depth Explanation:

IP Multicast vs. Broadcast:

A. TRUE→ Unlikebroadcast, which sends data toall hostsin a subnet,multicast only sends data to interested receivers,preventing flooding.

B. TRUE→Multicast optimizes bandwidth usageby sending asingle copy of data, which is thenreplicated at network routers only when necessary.

IP Multicast vs. Unicast:

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

D. FALSE→Multicast reduces the load on the sourcebecause asingle data stream serves multiple receiversinstead of sendingindividual unicast streams.

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