Free Huawei H12-821_V1.0 Practice Exam with Questions & Answers | Set: 6

Hello packets are the most basic and essential type of OSPF packets used for the following purposes:

Neighbor discovery– Routers use Hello packets to discover other OSPF routers on the same link.

Neighbor relationship establishment– When two routers exchange matching Hello packets, they move from the "Init" state to "2-Way" and further into adjacency states.

Neighbor relationship maintenance– Hello packets are sent periodically to ensure that neighbors are still reachable. If Hello packets are missed within the dead interval, the neighbor is considered down.

Neighbor deletionis not a direct function of Hello packets. Neighbor deletion results indirectly from missed Hello packets.

 Export Routing Policy Changes

When an export routing policy is modified, BGP does not automatically resend affected routes. Manual intervention, such as aclear ip bgpcommand, is required to resend Update messages reflecting the new policy.

 Incorrect Options

B.IGP routes can also be advertised into BGP using redistribution, not just thenetworkcommand.

C.A router can be configured with multiple BGP processes using different AS numbers (multi-instance BGP).

D.Open messages carry additional parameters such as AS number, Hold Time, and Router ID, not just the header.

 HCIP-Datacom-Core Reference

BGP policy and update behavior are detailed in the route control and redistribution chapters​​.

This statement isfalsebecauseIGMPv2 improves upon IGMPv1 by introducing the Leave Group message.

InIGMPv1, members leave silently, and the router waits for the timeout.

InIGMPv2, a host sends aLeave Groupmessage, prompting the router to send aGroup-Specific Queryto determine if other members are still present. If no responses are received, the group is pruned before timeout.

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

“IGMPv2 allows group members to actively send Leave messages, reducing unnecessary forwarding delays. This improves efficiency over IGMPv1.”

(Chapter: Multicast Protocols – Section: IGMP Versions)

The provided BGP error display shows the error timestamp as12:40:39 on March 22, 2010. The error message confirms a mismatch in the peer AS number, as indicated in the "Incorrect remote AS" error info. This eliminates options related to other causes, and the timestamp in Option A is incorrect ​.

Intra-area route calculation in OSPF involves only Router LSAs (Type 1) and Network LSAs (Type 2). Summary LSAs (Type 3) are used for inter-area routes and do not participate in intra-area route calculation. Therefore, the statement is false ​.

By default, BGP does not automatically summarize imported routes. Route summarization must be explicitly configured using thesummaryor similar commands ​.

Comprehensive and Detailed Step-by-Step Explanation:

1. Single-Hop BFD Session:

A single-hop BFD session is used to detect link failures between directly connected devices.

It is bound to thelocal IP addressand thepeer IP address, and the session relies on these parameters to establish connectivity.

2. Why Modifications Require Deletion:

BFD sessions are tightly bound to their configuration parameters (e.g., local and peer IP addresses).

Modifying these parameters is not supported for an existing session. Instead, you must delete the session and recreate it with the updated parameters.

3. Why the Statement is TRUE:

The statement correctly describes the behavior of BFD sessions, where modifying an existing session is not possible without deleting it first.

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 ​.

Comprehensive and Detailed Step-by-Step Explanation:

1. What is a Firewall Session?

A firewall session is an entry used to maintain the connection state of a protocol.

When a packet is forwarded, the firewall creates a session for it and tracks subsequent packets for the same connection to ensure efficient forwarding and security enforcement.

2. Analysis of Each Option:

Option A: Subsequent fragment

Incorrect.

A session is created for the initial fragment of a packet. Subsequent fragments are matched to the existing session and do not trigger the creation of a new session.

Option B: ICMP error packet

Incorrect.

ICMP error packets (e.g., Destination Unreachable) are considered exceptions and do not create new sessions.

Option C: GRE (Generic Routing Encapsulation)

Correct.

GRE is a tunneling protocol that encapsulates packets. A firewall creates a session for GRE traffic to track the state of the encapsulated connection.

Option D: TCP (Transmission Control Protocol)

Correct.

TCP is a connection-oriented protocol, and firewalls create sessions for TCP connections to track their state (e.g., SYN, SYN-ACK, FIN).

3. Summary:

The firewall creates sessions forGREandTCPprotocols.

Comprehensive and Detailed Step-by-Step Explanation:

1. What is VRF (Virtual Routing and Forwarding)?

VRF is a network virtualization technology that enables multiple isolated routing tables to coexist on a single physical device.

Each VRF instance is independent, which ensures separation between different VPNs or users.

2. Resources That VRF Can Independently Own:

Option A: Interface

Correct.

Each VRF instance can have its own set of interfaces. These interfaces are bound to a specific VRF, isolating traffic at the physical or logical port level.

Option B: Routing table

Correct.

VRF instances maintain independent routing tables. This ensures that routes for one VPN do not overlap or interfere with routes of another VPN.

Option C: MAC address table

Incorrect.

The MAC address table is part of Layer 2 operations and is shared by all VRF instances on the device. VRF operates at Layer 3 and does not isolate MAC address tables.

Option D: Routing protocol process

Correct.

Each VRF instance can run its own routing protocol processes (e.g., OSPF, BGP), and these processes are completely independent of other VRF instances.

3. Summary:

The correct resources that can be independently owned by a VRF instance areInterface,Routing Table, andRouting Protocol Process.