Free Practice Questions for Huawei H12-821_V1.0 Exam

Inasynchronousmode, the local device sends BFD control packets at predefined intervals, and the remote device monitors the receipt of these packets to detect connectivity issues. This is one of the two operating modes in BFD, the other beingdemandmode ​.

The output shows that the router with the IP10.0.12.2is the Backup Designated Router (BDR), as indicated in theState: BDRfield. The router ID is10.0.2.2, the interface cost is 1, and the IP address of the interface is10.0.12.2. Hence, C is the correct answer ​.

Comprehensive and Detailed Step-by-Step Explanation:

1. Understanding the Prefix List Configuration:

The command ip ip-prefix test index 10 permit 10.0.0.0 8 less-equal 32 defines the following:

The prefix base is 10.0.0.0 with a mask length of 8 bits.

The less-equal 32 condition allows routes with mask lengths ranging from 8 to 32 bits to match.

2. Analysis of Each Route:

Option A: 10.1.1.1/32

Correct.

The prefix 10.1.1.1/32 falls within the 10.0.0.0/8 network range and has a mask length of 32 bits, which satisfies the less-equal 32 condition.

Option B: 10.1.1.0/6

Incorrect.

The prefix 10.1.1.0/6 has a mask length of 6 bits, which is shorter than the base prefix length of 8. It does not satisfy the condition.

Option C: 10.1.1.0/24

Correct.

The prefix 10.1.1.0/24 falls within the 10.0.0.0/8 network range and has a mask length of 24 bits, which satisfies the less-equal 32 condition.

Option D: 10.0.0.0/16

Correct.

The prefix 10.0.0.0/16 falls within the 10.0.0.0/8 network range and has a mask length of 16 bits, which satisfies the less-equal 32 condition.

3. Summary:

The prefixes that match the configuration are 10.1.1.1/32, 10.1.1.0/24, and 10.0.0.0/16.

Huawei HCIA-Datacom Study Guide, Chapter "IP Prefix Lists."

Huawei Configuration Examples for ACL and Prefix Lists.

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

In IS-IS, theinterface costis a metric used to determine the best path to a destination. Lower-cost paths are preferred over higher-cost paths. By default, IS-IS interface costs can range from1 to 63.

Default Cost Range:

IS-IS allows the configuration of interface costs within the range of1–63by default. This range is sufficient for most networks.

Maximum Configurable Cost:

The maximum value that can be configured by default is63. If there is a requirement for a higher cost range, the metric-style can be changed towide, which allows the cost range to extend beyond 63.

Option A (67):Incorrect. 67 is not the maximum default value.

Option B (63):Correct. This is the maximum default cost value.

Option C (64):Incorrect. This is beyond the default range.

Option D (68):Incorrect. This is beyond the default range.

Understanding DHCPv6:

DHCPv6 (Dynamic Host Configuration Protocol for IPv6) is used to assign configuration parameters to IPv6 clients.

It supports bothstatefulandstatelessmodes:

Stateful: Assigns IPv6 addresses and other configuration parameters.

Stateless: Assigns only configuration parameters (e.g., DNS server) without providing IPv6 addresses.

HCIP-Datacom-Core Technology Training Material (IPv6 Address Configuration and DHCPv6)​​.

Analysis of Parameters:

A. Gateway address:

False. DHCPv6 does not assign the default gateway. Instead, the default gateway is advertised by routers usingRouter Advertisement (RA)messages in IPv6.

B. DNS server address:

True. DHCPv6 can assign the IPv6 address of DNS servers to the client.

C. IPv6 address/prefix:

True. In stateful mode, DHCPv6 assigns IPv6 addresses and prefixes to clients.

D. SNTP server address:

True. DHCPv6 can assign the address of an SNTP (Simple Network Time Protocol) server to synchronize time on the client.

 Notification Message Purpose

BGP Notification messages are used to report errors or terminate a connection. They do not request peers to resend routing information after routing policies are changed.

Routing updates following policy changes require manual resynchronization, not Notification messages.

 HCIP-Datacom-Core Reference

The purpose and usage of Notification messages are discussed in the BGP operation chapters​​.

For single-hop BFD (Bidirectional Forwarding Detection), the configuration must include the local and remote discriminators to uniquely identify the session endpoints. Additionally, enabling BFD globally is a prerequisite for initiating BFD sessions. Configuring multicast IP addresses isunnecessary for single-hop BFD, as it operates over direct links. Huawei's configuration guidelines specify these requirements to ensure effective deployment and operation of BFD​​.

 Understanding BFD (Bidirectional Forwarding Detection):

BFD is a protocol used to detect link faults quickly between two routers.

Single-hop BFD operates on directly connected links and is commonly used for fast fault detection in routing protocols like OSPF and BGP.

HCIP-Datacom-Core Technology Training Material (BFD Basics and Configuration)​​.

 Mandatory Configurations for Single-Hop BFD:

A. Configure the remote discriminator of a BFD session:The remote discriminator is used to uniquely identify the BFD session at the remote end. This is essential for session establishment.

B. Configure the local discriminator of a BFD session:The local discriminator uniquely identifies the BFD session at the local end. This is required to establish a BFD session.

D. Enable BFD globally:BFD must be enabled globally on the router for the protocol to operate and for session configurations to take effect.

 Optional Configuration:

C. Configure a multicast IP address for BFD:This is not required for single-hop BFD, as it operates over direct links using unicast communication. Multicast is used in other scenarios, like multi-hop BFD.

 Conclusion:The correct configurations for single-hop BFD areA,B, andD.

A stateful inspection firewall tracks the state of active connections. If a packet matches an existing session in the firewall's state table, it is allowed to pass. The diagram indicates that the TCP packet matches the session state, so the firewall forwards it ​.

BFD control packets are encapsulated in UDP packets, and the destination port number for multi-hop BFD control packets is 4784. This is a standardized port for multi-hop BFD operation ​.

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.