H12-821_V1.0 HCIP-Datacom-Core Technology V1.0 Question and Answers

ï‚· 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.

ï‚· 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.

ï‚· HCIP-Datacom-Core Reference

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

Comprehensive and Detailed Step-by-Step Explanation:

Analysis of BGP Attributes:

Original Next Hop:The output shows that the original next hop of the route is 172.16.1.2. (A is correct).

Local Router ID:The local BGP router ID is 10.1.1.1, as displayed. (B is correct).

Local AS Number:The local AS number is 100, as displayed. (C is correct).

Incorrect Option:

Local_Pref:Although Local_Pref is an important attribute, this route is marked as invalid due to "IP unreachable" and thus cannot be preferentially selected.

InIPv6, fragmentation is handledonly at the source node. Intermediate routersdo not fragment packets. Instead, if a packet is too large for the next link, the router sends back anICMPv6 Packet Too Bigmessage to the source, which then adjusts its packet size.

This design:

Reduces processing load on intermediate devices.

Supports Path MTU Discovery (PMTUD).

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

“In IPv6, routers do not perform fragmentation. Only the source device fragments packets if needed, based on ICMPv6 feedback.”

(Chapter: IPv6 Fundamentals – Section: Fragmentation and PMTUD)

ï‚· IPv6 Address Behavior

Manually configured link-local addressesdo not have a higher prioritythan automatically generated ones; they coexist and are equally preferred for local communication.

The other statements are true:

A.Link-local addresses can use the EUI-64 method for quick generation.

B.Anycast addresses are only used as destination addresses.

C.An interface can have multiple global unicast addresses with different prefixes.

ï‚· HCIP-Datacom-Core Reference

IPv6 address types and priority behaviors are detailed in the IPv6 addressing sections​​.

Comprehensive and Detailed Step-by-Step Explanation:

VRRP Virtual MAC Address Format:

The VRRP virtual MAC address is generated using the format:0000-5e00-01XX, whereXXrepresents the VRID in hexadecimal.

Calculation:

VRID = 1 → Hexadecimal =01.

Virtual MAC =0000-5e00-0101.

Correct Option:

C (0000-5e00-0101).

Comprehensive and Detailed In-Depth Explanation:

When a packet is checked against anAccess Control List (ACL), it is processed based on rule matches.

"Unmatched" scenariosoccur if:

A. TRUE→ The packetdoes not match any ACL rule.

C. TRUE→No ACL is configured, so there are no rules to match.

D. TRUE→An empty ACL exists, meaning no rules are defined.

B is incorrectbecauseif the packet matches a deny rule, it is "matched" and explicitly dropped, not "unmatched".

📖Reference:Huawei HCIA-Datacom Study Guide, ACL Rule Matching and Processing Logic.

Comprehensive and Detailed Step-by-Step Explanation:

1. Port Priority in RSTP:

RSTP (Rapid Spanning Tree Protocol) elects root and designated ports based on port priority and port ID.

Port priority is a configurable value that helps determine which port becomes the root or designated port when multiple ports are eligible.

The port ID consists of the port priority and port number. When priorities are equal, the port number is used as a tiebreaker.

2. Default Port Priority on Huawei Switches:

On Huawei switches, the default port priority is128.

This value can be adjusted in increments of 16 using the command stp port priority.

3. Analysis of Options:

Option A: 1

Incorrect. This is not the default port priority value.

Option B: 128

Correct. This is the default port priority value on Huawei switches.

Option C: 4096

Incorrect. This is not a valid default port priority value.

Option D: 32768

Incorrect. This is the default bridge priority, not the port priority.

4. Summary:

The default port priority on Huawei switches is128.

Huawei HCIA-Datacom Study Guide, Chapter "RSTP Port Role Election."

IEEE 802.1D-2004: Rapid Spanning Tree Protocol (RSTP).

ï‚· VRRP and BFD Association:

VRRP (Virtual Router Redundancy Protocol) is used to provide gateway redundancy by electing amasterandbackuprouter.

Associating VRRP with BFD (Bidirectional Forwarding Detection) allows faster detection of faults on the master device or the link between the master and the backup.

HCIP-Datacom-Core Technology Training Material (VRRP and BFD Association)​.

ï‚· Master_Down_Timer Behavior:

Normally, when a VRRP backup device detects that the master is down (through missed VRRP advertisements), theMaster_Down_Timerdictates the failover timing.

However, when VRRP is associated with BFD:

BFD detects faults immediately (sub-second detection).

The backup device doesnot wait for the Master_Down_Timerto expire. Instead, it immediately assumes the master role upon fault detection by BFD.

A screenshot of a computer Description automatically generated

Explanation of Root Port Election in STP:

In a Spanning Tree Protocol (STP) network, theRoot Portis selected on each switch (except the Root Bridge). The Root Port is the port with thelowest path costto the Root Bridge. If there is a tie in path cost, the following criteria are used in sequence to break the tie:

Steps for Root Port Election in Sequence:

RPC Comparison (Root Path Cost):

The port with thelowest Root Path Costis preferred.

Root Path Cost is the cumulative cost of the path to the Root Bridge.

Peer BID (Bridge ID) Comparison:

If the Root Path Costs are equal, theBridge IDof the connected switch (peer) is compared.

The port connecting to the switch with thelower Bridge IDis preferred.

Peer PID (Port ID) Comparison:

If the Bridge IDs are equal, thePort IDof the peer's sending port is compared.

The port connecting to thelower Port IDis preferred.

Local PID (Port ID) Comparison:

If all else is equal, theLocal Port IDof the switch is used.

The port with thelower Local Port IDis selected.

In SNMP (Simple Network Management Protocol), the MIB (Management Information Base) defines the attributes of a managed device. It acts as a structured database of managed objects, each described by a unique OID (Object Identifier). These objects provide critical information and control interfaces for network management. Other elements like the agent (manages the MIB) and NMS (queries the agent) do not define attributes but interact with the MIB ​.

The prefix list permits the prefix1.1.1.1/24with a mask length greater than or equal to/26and less than or equal to/32. This means only prefixes with the base1.1.1.1and mask lengths between/26and/32will be permitted. Routes like1.1.1.2/16and1.1.1.1/24do not meet the mask length criteria, so they will be denied. Conversely, routes like1.1.1.1/26and1.1.1.1/32satisfy the condition and will be permitted ​.

Root protection ensures that a designated port does not become a root port by discarding superior BPDUs. However, if superior BPDUs are no longer received, the port can return to its original forwarding state, meaning its role can change. This makes option B incorrect, while the other options correctly describe RSTP behavior ​.

IS-IS uses a two-level hierarchy:

Level-1 routersoperate within a single area and cannot exchange routing information with routers in other areas directly.

To reach external areas (the IS-IS backbone or other areas), Level-1 routers rely onLevel-1-2 routers, which perform inter-area route redistribution.

Therefore, a Level-1 routermust use a Level-1-2 routeras a gateway to reach destinations outside its own area.

A is correct– Local attack defense can classify and prioritize packets (e.g., OSPF, BGP, SSH) andensure critical protocols are processed firstby the CPU.

B is correct– Thedynamic link protection functionensures session-based applications (like SSH)are not disruptedeven during a CPU attack.

C is false– Different protocols havedifferent importance levels, soindividual rate limitsshould be configured, not a uniform one.

D is correct– CPU protectionalso applies to management interfaces, such as those used for Telnet, SSH, or SNMP.

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

“Devices support local attack defense by classifying packets, setting priorities, and limiting rates to protect CPU resources. These policies also apply to the management interface.”

(Chapter: Network Security – Section: Local Attack Defense)

ï‚· GRE Characteristics

GRE doesnotinherently support encryption or authentication. It is a tunneling protocol for encapsulating packets, and data security features must be implemented using other protocols such as IPsec.

Other correct attributes of GRE include:

B.Supports multicast transmission.

C.Acts as a Layer 3 VPN encapsulation technology.

D.Can work with VPN protocols like IPsec for better security.

ï‚· HCIP-Datacom-Core Reference

GRE features and limitations are discussed in VPN encapsulation technology chapters​​.

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:

TheNetwork Entity Title (NET)is a unique identifier assigned to an IS-IS router. It is derived from theNetwork Service Access Point (NSAP)address and consists of the following components:

Area Address:

Identifies the area in which the router resides.

Multiple routers in the same IS-IS area must have the same area address.

System ID:

Uniquely identifies the router within the IS-IS area.

The System ID is typically derived from the router's loopback IP address or another unique value.

SEL (Selector Field):

The SEL field is always set to00for IS-IS NETs.

The NET is used by IS-IS for route calculation and to identify the router within the IS-IS domain. Therefore, the statement isTRUE.

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

Comprehensive and Detailed Step-by-Step Explanation:

1. Understanding IGMP Version Compatibility:

IGMP (Internet Group Management Protocol) supports multiple versions, such as IGMPv1, IGMPv2, and IGMPv3.

A device running alater versionof IGMP is backward-compatible and can identify Report messages from earlier versions.

However, a device running anearlier versionof IGMP cannot recognize the newer features or formats of later IGMP versions.

2. Best Practice:

To avoid compatibility issues, the IGMP version configured on the switch should be thesame as or later thanthe version used by the member hosts in the network.

3. Why the Statement is TRUE:

The statement is correct because it describes the compatibility behavior of IGMP versions and advises setting the switch IGMP version appropriately.

Comprehensive and Detailed In-Depth Explanation:

STP (Spanning Tree Protocol) BPDUsdo not contain an explicitport role field. Instead, roles are determined indirectly.

RSTP (Rapid Spanning Tree Protocol)modifies BPDU structureby using theFlags fieldto indicate:

Port roles (Root, Designated, Alternate, Backup)

Proposal/Agreement (P/A) handshake mechanism

The correct field thatspecifies the port role in RSTP BPDUsisFlags.

📖Reference:Huawei HCIA-Datacom Study Guide, RSTP BPDU Structure and Flags Field.

ï‚· 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)​​.

ï‚· 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)​.

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

Understanding DIS Election in IS-IS:

On an IS-IS broadcast network, aDesignated Intermediate System (DIS)is elected to create and update pseudonodes for efficient communication.

The election is based on the following criteria:

DIS Priority:The router with the highest priority is elected as the DIS.

Router ID (tie-breaker):If priorities are equal, the router with the highest Router ID is elected.

Analyzing the DIS Priorities and Router IDs:

R1: Priority = 64, Router ID = 1.1.1.1

R2: Priority = 1, Router ID = 2.2.2.2

R3: Priority = 127, Router ID = 3.3.3.3

R4: Priority = 10, Router ID = 4.4.4.4

Among the routers,R3 has the highest DIS priority (127), making it the DIS.

Correct Option:

Option B (R3):Correct, as R3 has the highest priority.

Option A (R1):Incorrect, as its priority is lower (64).

Option C (R4):Incorrect, as its priority is lower (10).

Option D (R2):Incorrect, as its priority is the lowest (1).

Comprehensive and Detailed Step-by-Step Explanation:

1. How Firewalls Match Security Policies:

Firewalls usesecurity policiesto define rules for filtering traffic.

Each policy containsmatching conditions(e.g., source IP, destination IP, protocol, etc.) and anaction(e.g., permit or deny).

Traffic is evaluated against these policies in sequential order, and the first matching policy is applied.

2. Analysis of Each Statement:

Option A: Multiple values can be configured for a single matching condition, and the values are logically ANDed.

Incorrect.

Multiple values for a single matching condition (e.g., multiple source IPs) are logicallyORed, not ANDed. For example, traffic from any of the specified source IPs matches the policy.

Option B: If a security policy contains multiple matching conditions, the relationship between them is AND.

Correct.

When a policy has multiple matching conditions (e.g., source IP AND destination IP AND protocol), all conditions must be met for the policy to match.

Option C: The system has a default security policy named default, where all matching conditions are any and the default action is permit.

Incorrect.

The default security policy typically denies all traffic unless explicitly permitted by user-defined policies.

Option D: When multiple security policy rules are configured, they are sorted in a list by configuration sequence by default. A security policy rule configured earlier is placed higher in the list and has a higher priority.

Correct.

Security policies are processed in sequential order based on their configuration sequence. Policies configured earlier have higher priority and are evaluated first.

3. Summary:

The correct statements areBandD.

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.

A is correct– Removing unused accounts helpsminimize the risk surface.

B is false– Email isnot a secure methodfor transferring sensitive information like passwords, even if encrypted.

C is correct–Unique administrator accountshelp with accountability and tracking.

D is false–Long-term password validityreduces security. Passwords should be rotated regularly.

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

“To secure admin access, avoid account sharing, delete inactive users, and periodically update credentials through secure channels.”

(Chapter: Device Security – Section: Account Management)

Comprehensive and Detailed Step-by-Step Explanation:

1. Understanding LSA Filtering in OSPF and IS-IS:

The filter-policy command is used in OSPF and IS-IS to control which routing information isimported into the local routing tableoradvertised to other neighbors.

However, itcannot filter LSAs forwarded by neighbors. In OSPF and IS-IS, LSAs are always forwarded unchanged within the area to ensure all routers have a consistent link-state database.

Filtering only affects the routes that are installed into the local routing table or advertised to other areas or neighbors.

2. Why the Statement is False:

LSAs are forwarded without being filtered. This ensures link-state protocols maintain the same network topology view across the network.

The filter-policy import command only controls routes that are installed into the local routing table, not the forwarding of LSAs.

3. Summary:

The statement is FALSE because LSAs cannot be filtered by filter-policy import.

Huawei HCIA-Datacom Study Guide, Chapter "OSPF Route Filtering."

RFC 2328: OSPF Version 2, LSA Propagation Rules.

Comprehensive and Detailed Step-by-Step Explanation:

Portal Authentication:

Portal authentication uses a web-based mechanism where clients are redirected to a login page.

Communication between the access device and Portal server uses HTTP or HTTPS protocols.

Correct Statements:

Option A:HTTP or HTTPS is used for Portal authentication.

Option D:Portal protocol packets are transmitted overTCPfor reliable communication.

Incorrect Statements:

Option B:Port 2000 is not the default for processing Portal packets.

Option C:The default destination port for communication with the Portal server is not 50100.

ï‚· IGMP:Manages IPv4 multicast group members and runs on the multicast network's last segment (that is, the network segment where a Layer 3 network device is connected to user hosts).

ï‚· PIM:Sends multicast data over the network to the multicast device that is connected to group members that have requested the multicast data, implementing multicast data forwarding based on routes.

ï‚· IGMP Snooping:Manages and controls the forwarding of multicast data packets to effectively suppress the flooding of multicast data packets on the Layer 2 network.

ï‚· IGMP (Internet Group Management Protocol):

IGMP is used by hosts and adjacent multicast routers to establish and maintain multicast group memberships on a local subnet.

It allows a host to inform a multicast router of its desire to receive multicast traffic for a specific group.

It operates at Layer 3 and runs on the last segment of the network.

HCIP-Datacom-Core Technology Training Material (Multicast Fundamentals)​.

ï‚· PIM (Protocol Independent Multicast):

PIM is a routing protocol designed for efficient routing of IP multicast traffic. It determines the paths over which multicast packets should be forwarded.

PIM is "protocol-independent" because it uses the underlying unicast routing table for RPF (Reverse Path Forwarding) checks.

It is responsible for distributing multicast data throughout the network.

Comprehensive and Detailed Step-by-Step Explanation:

Overview of IGMP Versions:

IGMPv1:The simplest version, supports basic group membership management using Report messages but lacks Leave messages.

IGMPv2:Adds features like Leave messages and Group-Specific Queries.

IGMPv3:Supports specifying multicast sources for Source-Specific Multicast (SSM).

Feature Supported by All Versions:

Report messagesare fundamental to IGMP functionality and are supported in all three versions.

Features Not Supported by All Versions:

Group-Specific Queries (A):Supported in IGMPv2 and IGMPv3.

Leave Messages (B):Introduced in IGMPv2.

Specifying Multicast Sources (D):Introduced in IGMPv3.

Routing Entries in PIM

(S, G) entries: Represent the shortest path tree (SPT) from a specific source (S) to a specific multicast group (G). These entries are created after data packets are transmitted directly from the source to the receivers.

(S, G) entries are used in both PIM-DM and PIM-SM modes.

PIM-DM and PIM-SM Modes

InPIM-DM, multicast traffic is initially flooded throughout the network and pruned where no receivers exist. (S, G) entries represent source-specific paths created after the flooding stage.

InPIM-SM, multicast traffic initially flows through a shared tree, but (S, G) entries are created when the network switches to the SPT for more efficient forwarding.

HCIP-Datacom-Core Reference

The functionality and application of (S, G) routing entries are detailed in multicast and PIM configuration chapters​​.

In asynchronous mode, two devices exchange BFD Control packets to monitor connectivity. However, this mode does support the echo function, which tests bidirectional paths by sending packets that loop back to the origin. This statement is incorrect. Demand mode, on the otherhand, minimizes the control packet exchange, relying on periodic echo packets if configured. Huawei's BFD configuration guides emphasize these distinctions ​.

Based on the MSTP configuration shown, the role of the switch in MSTI 1 cannot be determined without additional details about the topology or priority values of other switches in the instance. The role could be a root switch, secondary root, or non-root, depending on these factors ​.

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.

The defaultSTP priorityon Huawei switches (and in the IEEE standard) is32768.

Lower priority values increase the likelihood of a switch becoming the root bridge. You can configure this value in increments of 4096.

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

“The default bridge priority of Huawei switches is 32768. The root bridge is elected based on the lowest bridge ID, which consists of the priority and MAC address.”

(Chapter: Spanning Tree Protocols – Section: RSTP and Bridge Election)

Comprehensive and Detailed Step-by-Step Explanation:

WAN Definition:

A WAN is a large-scale network spanning a wide geographical area, connecting smaller networks such as LANs and MANs.

Use Cases:

WANs are commonly used for interconnecting campus networks, branch offices, and data centers over long distances.

Correct Statement:

The statement accurately describes the purpose and scope of WANs.

A is false– Thedefault value of Local_Pref is 100, not 0.

B is false–Local_Pref is not advertised to EBGP peers, it is only sent toIBGP peers.

C is correct– TheLocal_Pref value stays constantunless modified by a route-policy or filter.

D is correct–Higher Local_Pref values indicate preferred paths, so BGP prefers the path with the highest Local_Pref among multiple options.

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

“Local_Pref is used to select the best outbound path for traffic leaving the AS. It is only shared among IBGP peers and defaults to 100. The higher the value, the more preferred the route.”

(Chapter: BGP Path Attributes – Section: Local Preference)

In an OSPF broadcast or NBMA network with at least two routers, one router must act as the DR (Designated Router), and another as the BDR (Backup Designated Router) to ensure efficient communication and reduce the number of adjacencies. This is a requirement for OSPF operation in such network types ​.

Comprehensive and Detailed In-Depth Explanation:

Stub areasdo not allowexternal routes(Type 5 LSAs).

SinceASBRs are responsible for redistributing external routesinto OSPF, theycannot exist in a stub area.

If an ASBR were placed in a stub area, it would attempt to inject external routes into the OSPF domain, which contradicts the stub area rules.

To allow external routes,Not-So-Stubby Areas (NSSAs)are used instead, which allowASBRsand useType 7 LSAsto carry external routes.

📖Reference:Huawei HCIA-Datacom Study Guide, OSPF Area Types and ASBR Restrictions.

Comprehensive and Detailed In-Depth Explanation:

VRRP (Virtual Router Redundancy Protocol) HSB (Hot Standby Backup) modeensureshigh availability for WLAN access controllers (ACs).

A. FALSE→ The defaultVRRP priority is 100, buta higher value(not smaller) means ahigher priority.

B. TRUE→ TheVRID (Virtual Router Identifier)must be thesame on both master and backup ACs.

C. TRUE→ Thevirtual IP address must matchfor seamless failover.

D. FALSE→ Thedefault VRRP advertisement interval is 1 second. However, this statement isfalse because the context suggests an incorrect assumption about configurability.

📖Reference:Huawei HCIA-Datacom Study Guide, VRRP in WLAN Deployments.

Multi-channel protocols such as H.323 and FTP use separate control and data channels. H.323 uses different channels for call signaling and media streaming, while FTP uses a control channel for commands and a data channel for file transfers. Telnet and SMTP are single-channel protocols ​.

When configuring VRRP, the virtual router priority and virtual IP address are mandatory because they define the VRRP instance and its role within the group. Preemption mode and preemption delay are optional configurations that influence how routers take over the master role when priorities change. These are not mandatory for the VRRP protocol to function ​.

The command output indicates that the OSPF neighbor state isFulland that the neighbor relationship has been established. The statement confirms that the negotiation process during the exchange of DD (Database Description) packets has determined the role of the router, with the local device becoming the slave in the Master-Slave relationship, which is critical for LSA synchronization. The other options do not align with the output or OSPF principles ​

Thesilent-interfacecommand disables the sending of OSPF packets, including Hello packets, on the specified interface, which prevents the establishment of OSPF neighbor relationships. However, the interface can still advertise directly connected routes through other interfaces, making Option C incorrect ​.

Apseudonodein IS-IS is a logical representation of a broadcast network segment (e.g., Ethernet) where theDesignated Intermediate System (DIS)generates an LSP on behalf of the LAN.

Pseudonode LSPs contain:

Interface information(i.e., the interface that connects to the pseudonode)

Neighbor information(adjacencies with other routers on the LAN)

Protocol information(e.g., supported address families)

However,route information is not containedin LSPs generated by pseudonodes because routing information is advertised in theLSPs generated by the routers themselves, not the pseudonode.

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

“Pseudonode LSPs contain information about the broadcast link, including interface and neighbor data. They do not advertise routing entries.”

(Chapter: IS-IS Advanced Features – Section: DIS and Pseudonodes)

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)andLocal_Preferenceare 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​​.

ARP spoofing is a Layer 2 attack, as it targets ARP tables in switches or end devices. All other attacks, including IP spoofing, ICMP attacks, and Smurf attacks, are network layer (Layer 3) attacks ​.

Comprehensive and Detailed Step-by-Step Explanation:

1. Overview of IP Multicast:

IP multicast is a method of delivering data from one source to multiple destinations simultaneously.

Unlike unicast (one-to-one communication) or broadcast (one-to-all communication), multicast isone-to-many, allowing data to be sent only to subscribers (multicast group members).

This significantly conserves bandwidth and reduces the load on the network because the source only sends a single stream of data, which is replicated by multicast routers as needed.

2. Use Cases for IP Multicast:

IP multicast is widely used in network services that involve real-time or large-scale data delivery, such as:

IPTV (Internet Protocol Television):Broadcasting live TV streams.

Real-Time Data Transmission:Delivering stock market data, sensor updates, etc.

Multimedia Conferencing:Supporting group calls, webinars, and online meetings.

3. Why the Statement is TRUE:

IP multicast reduces unnecessary traffic and maximizes efficiency, making it ideal for these types of network services.

The forwarding plane of a switch consists of data forwarding hardware, such as line cards or forwarding engines, and is responsible for tasks like encapsulating/decapsulating packets, providing high-speed data channels, and collecting packet statistics. However, main control boards are part of the control plane, not the forwarding plane. This distinction ensures a separation of data forwarding and control functionalities ​.

Understanding the LSDB and Level-2 DIS Election in IS-IS:

In IS-IS, theDesignated Intermediate System (DIS)is elected for both Level-1 and Level-2 on broadcast networks to manage the link-state database (LSDB) and reduce the number of LSAs exchanged.

The election of the DIS is based on thehighest priority. If the priority is the same, the router with thehighest System IDbecomes the DIS.

HCIP-Datacom-Core Technology Training Material (IS-IS DIS Election)​​.

Analyzing the LSDB:

From the LSDB ofR1, the Level-2 link-state database includes the following entries:

LSPID 0100.0000.3003.00-00: This is R3, and it is present in the Level-2 LSDB with the sequence number and checksum details.

Other routers (R1, R2, R4) are present but do not have the characteristics of the Level-2 DIS in this topology.

Based on the System IDs,R3 (0100.0000.3003)has the highest System ID, making it theLevel-2 DIS.

Conclusion:

The Level-2 DIS on the network isR3, based on the election rules and the LSDB information shown in the figure.

TheOriginattribute in thedisplay bgp routing-tableoutput is marked asi, indicating that the route was injected into the BGP routing table using thenetworkcommand. The other options are incorrect because the AS path is not displayed, the MED is0, and the route is marked as the best (>), meaning it is the optimal route ​.

ï‚· 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.

ï‚· HCIP-Datacom-Core Reference

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

ï‚· ACL Modification

Named ACLs can be modified after their creation. Unlike numbered ACLs, named ACLs provide greater flexibility for editing individual rules without deleting the entire ACL.

Therefore, the statement is incorrect.

ï‚· HCIP-Datacom-Core Reference

The flexibility and editability of named ACLs are discussed in the ACL configuration sections​​.

ï‚· BGP Route Flapping and Mitigation

While route flapping is a concern in large-scale networks, BGP employs mechanisms such asRoute Dampeningto mitigate its impact. Route dampening suppresses frequently flapping routes for a period of time to reduce resource consumption and network instability.

Therefore, it is incorrect to state that the issue cannot be resolved in BGP.

ï‚· HCIP-Datacom-Core Reference

The mechanism of route dampening is detailed in the BGP optimization chapters​​.

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 ​.

The MED (Multi-Exit Discriminator) is an optional, non-transitive attribute used to influence the exit path. MED is considered after attributes such as Local-Preference, AS-Path, and Origin during route selection. By default, if a MED value is missing, it is treated as 0 unless thebestroute med-none-as-maximumcommand is configured to treat it as 4294967295 ​.

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 ​.

1. Understanding Prefix List Configuration:

The command ip ip-prefix huawei index 10 permit 10.1.1.0 24 greater-equal 26 defines a prefix filter:

The base prefix is 10.1.1.0/24.

The greater-equal 26 condition specifies that the mask length of matching prefixes must beat least 26 bits.

If the less-equal parameter is not explicitly defined, the default value is32, meaning the longest possible mask length for IPv4.

2. Explanation of Values:

greater-equal-value: Specifies the minimum mask length. In this case, the value is26.

less-equal-value: Specifies the maximum mask length. Since it is not explicitly configured, the default value is32.

3. Summary:

greater-equal-value = 26

less-equal-value = 32

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

IGMPv3 builds on IGMPv1 and IGMPv2 by supporting all previous query types, including General Query and Group-Specific Query, while introducing Source/Group-Specific Query. This enhancement allows finer control over multicast group membership ​.

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.

ï‚· LSP Generation in IS-IS

IS-IS routers generate new Link State Packets (LSPs) under the following conditions:

Interface Status Changes: When IS-IS interfaces go up or down, the link state changes, triggering LSP updates.

Periodic Updates: IS-IS periodically regenerates LSPs to ensure link-state information remains synchronized across the network.

Interface Metric Changes: Any modification to interface costs results in a new LSP to reflect the updated cost in the network.

ï‚· Incorrect Option

C. Inter-area IP routes change is incorrect because IS-IS does not inherently differentiate between areas for LSP generation.

ï‚· HCIP-Datacom-Core Reference

IS-IS LSP generation rules are detailed in the IS-IS configuration and implementation chapters​​.

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 ​.

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).

A screenshot of a computer Description automatically generated

Explanation of VRRP Roles and Their Functions:

InVRRP (Virtual Router Redundancy Protocol), devices are assigned roles as eitherMasterorBackupafter an election process. Each role has specific responsibilities to ensure the availability of the virtual IP address.

Matching Roles and Mechanisms:

Master:

Periodically send VRRP Advertisement packets.

The Master device sends advertisement packets to inform Backup devices that it is active.

Respond to an ARP request destined for a virtual IP address with an ARP reply carrying the virtual MAC address.

The Master device is responsible for responding to ARP requests for the virtual IP and forwarding traffic for it.

Backup:

Transition from Master to Backup immediately if a VRRP Advertisement packet with a higher priority is received.

A Backup device becomes Master only if the current Master stops sending advertisement packets or has a lower priority.

Discard IP packets destined for the virtual IP address.

Backup devices do not process traffic for the virtual IP address unless they become the Master.

Comprehensive and Detailed Step-by-Step Explanation:

1. Overview of PBR (Policy-Based Routing):

Policy-Based Routing (PBR) allows you to override traditional routing decisions by defining user-specific policies.

Interface-Based PBR: Applied to packets arriving at a specific interface and affects traffic being forwarded through the device.

Local PBR: Applied to traffic generated by the local router itself (e.g., locally originated packets such as management traffic).

2. Analysis of Each Statement:

Option A: Interface-based PBR takes effect only for forwarded packets.

Correct (True Statement).

Interface-based PBR applies only to packets arriving at a specific interface and being forwarded through the router. It does not affect locally originated traffic.

Option B: Local PBR takes effect only for locally originated packets.

Correct (True Statement).

Local PBR specifically applies to traffic generated by the router itself, such as pings, SNMP requests, or routing protocol updates.

Option C: Interface-based PBR is configured on an interface and takes effect only for incoming packets on the interface.

Correct (True Statement).

Interface-based PBR is applied directly on the interface using commands like policy-based-route. It only affects traffic entering the specified interface.

Option D: Local PBR is configured in the protocol view.

Incorrect (False Statement).

Local PBR is not configured in the protocol view. It is typically configured using the command local-policy in the system view to handle traffic generated by the router.

3. Summary:

Correct Answer:D (Local PBR is NOT configured in the protocol view).

Huawei HCIA-Datacom Study Guide, Chapter "Policy-Based Routing."

Comprehensive and Detailed Step-by-Step Explanation:

1. What is GRE (Generic Routing Encapsulation)?

GRE is a tunneling protocol that allows the encapsulation of various types of packets (e.g., IPv4, IPv6, multicast, etc.) to be transmitted over another protocol (e.g., IP).

GRE is used to create point-to-point connections over heterogeneous networks.

2. Analysis of Each Option:

Option A: GRE is a Layer 2 VPN encapsulation technology.

Incorrect.

GRE operates at Layer 3 (Network Layer) and encapsulates Layer 3 packets. It is not a Layer 2 VPN encapsulation technology like MPLS or Ethernet-over-IP.

Option B: GRE enables encapsulated data packets to be transmitted over another network layer protocol, but cannot encapsulate multicast data.

Incorrect.

GRE supports the encapsulation and transmission of multicast data packets. This is one of its key features, making it suitable for protocols like OSPF and multicast applications.

Option C: GRE tunnels can work with IPsec to ensure the security of multicast services such as voice and video.

Correct.

GRE by itself does not provide encryption or security. However, GRE can work with IPsec to secure the encapsulated traffic, including multicast data, for services like voice and video.

Option D: GRE tunnels can extend the working range of network protocols with hop limits.

Correct.

GRE encapsulates packets, effectively resetting their hop limits and allowing protocols with limited hop counts (e.g., RIP) to work over larger networks.

3. Summary:

The correct options areCandD.

By default, a router interface sends PIM (Protocol Independent Multicast) Hello messages every 30 seconds to maintain neighbor relationships. This interval can be adjusted using configuration commands ​.

Comprehensive and Detailed Step-by-Step Explanation:

1. Understanding Hybrid Interfaces on a Layer 2 Switch:

Layer 2 switches support different interface types, such asaccess,trunk, andhybridinterfaces.

Atrunk interfaceallows traffic from multiple VLANs to pass through, but frames belonging to the native VLAN are sent untagged, while all other VLAN frames are tagged.

Ahybrid interfaceis more flexible:

It allows traffic from multiple VLANs to pass through, just like a trunk interface.

However, you can configure whether frames for specific VLANs are tagged or untagged as they leave the interface. This feature is useful in certain networking scenarios, such as connecting devices that do not support VLAN tagging.

2. Key Differences Between Trunk and Hybrid Interfaces:

A screenshot of a computer Description automatically generated

3. Why the Statement is TRUE:

The statement accurately describes the functionality of a hybrid interface:

It supports traffic from multiple VLANs.

It allows administrators to configure whether outgoing frames are tagged or untagged for specific VLANs.

4. Summary:

The statement isTRUEbecause hybrid interfaces on a Layer 2 switch support traffic from multiple VLANs and allow flexible tagging configurations.

Configuration Analysis:

OnR2, the following configuration has been applied:

acl 200

rule deny source 10.1.0.0 0.0.3.0

rule permit

#

ospf 1

filter-policy 2000 import

This configuration usesACL 200to filter routes during import into the OSPF routing table on R2.

Rule deny source 10.1.0.0 0.0.3.0:Blocks routes in the range10.1.0.0/24 to 10.1.3.0/24(inclusive).

Rule permit:Allows all other routes to be imported.

Impact of ACL 200 on Route Import:

10.1.0.0/24 to 10.1.3.0/24:These subnets are explicitly denied by ACL 200 and will not appear in R2's routing table.

10.1.4.0/24 and beyond:These subnets are permitted by therule permitstatement and will be imported into R2's routing table.

Routing Table Entries on R2:

Option A (10.1.4.0/24):Exists in R2's routing table because it is permitted.

Option B (10.1.3.0/24):Does not exist because it is denied by ACL 200.

Option C (10.1.2.0/24):Does not exist because it is denied by ACL 200.

Option D (10.1.1.0/24):Does not exist because it is denied by ACL 200.

A (10.1.4.0/24)

ï‚· ACL Number Ranges

Basic ACLs: Numbered from 2000 to 2999.

Advanced ACLs: Numbered from 3000 to 3999.

Layer 2 ACLs: Numbered from 5000 to 5999.

User-defined ACLs: Numbered from 4000 to 4999.

ï‚· HCIP-Datacom-Core Reference

ACL classifications and their number ranges are covered in the ACL principles and configuration chapters​​.

In BGP and other TCP-based protocols like OSPF and IS-IS, when devices havedifferent Hold Times, thesmaller value is chosenafter negotiation. This ensuresfaster detectionof communication loss.

The Keepalive and Hold Timers are negotiated during the establishment of a BGP session.

The smaller Hold Timeis used to maintain symmetry and prevent timeouts.

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

“When negotiating Hold Time, both ends agree to use the smaller of the two values. This value is used to detect failures faster.”

(Chapter: BGP Fundamentals – Section: BGP Session Establishment)

The information provided indicates that the configured query interval is 60 seconds, which applies to general queries. Group-specific queries are sent at a shorter interval, usually derived from the maximum response time. Therefore, the statement about a 60-second interval for group-specific queries is false. Other statements regarding maximum response time (10s), IP address, and IGMP version (V2) are correct ​.

The Link State ID in a Type 3 LSA (Summary LSA) indicates the network or subnet being summarized, not the router ID of an ABR. All other statements accurately describe OSPF functionality, making D the false statement ​.

Understanding the Network Setup:

The OSPF network consists of three areas (Area 1, Area 0, and Area 2).

The server's subnet192.168.1.0/24is directly connected to R1 and imported into OSPF using the command:

import-route direct type 1 cost 2

Thetype 1specifies the route as anOSPF Type 1 external route, meaning both the external cost and the internal OSPF cost will be included when calculating the total cost.

The external cost specified for the imported route is2.

Cost Calculation to R2:

The interfaces between the routers are GE interfaces, and the default cost for GE interfaces is1.

The path from R2 to the server goes through the following hops:

R2 → R1:Cost = 1 (intra-area link).

R1 → Server:External cost = 2 (specified in theimport-routecommand).

Total cost to R2:

Intra-area cost (1) + External cost (2) = 3

Verification of Each Option:

Option A (2):Incorrect. This only accounts for the external cost, ignoring the internal OSPF cost.

Option B (4):Incorrect. This overestimates the cost by adding an extra hop.

Option C (3):Correct. The total cost is3(1 for the intra-area link + 2 for the external cost).

Option D (1):Incorrect. This ignores the external cost of the imported route.

The scenario describes a mismatch in OSPF network types between two connected routers: one set to Point-to-Point (P2P) and the other set to Point-to-Multipoint (P2MP). While aligning Hello intervals may seem sufficient for establishing an OSPF neighbor relationship, the fundamental mismatch in network types introduces issues.

OSPF Network Types

P2P: Assumes a direct connection with a single neighbor, uses faster convergence and simpler LSDB synchronization.

P2MP: Supports multiple neighbors on a single interface, requiring different handling for DR/BDR roles and LSDB updates.

Impact of Network Type Mismatch

If Hello intervals are aligned, adjacency establishment might occur. However, mismatched network types affect neighbor role assignment and LSDB synchronization.

P2P expects a direct link and would handle updates differently than P2MP, which assumes multiple neighbors. This leads to inconsistencies in route calculation and forwarding.

HCIP-Datacom-Core Reference

OSPF Basics and Configuration​clearly outlines the criticality of consistent network type configuration for stable OSPF operation.

Lab examples in the HCIP Datacom Lab Guide​further demonstrate the consequences of such mismatches, including unstable neighbor states and incomplete LSDB synchronization.

Hence, the statement that neighbor relationships and LSDB synchronization remain unaffected is incorrect. Proper OSPF operation requires matching network types in addition to aligned Hello intervals.

After Layer 3 roaming, the STA’s traffic is forwarded from the Foreign AP (FAP) to the Foreign AC (FAC), and then to the Home AC (HAC) before reaching the upper-layer network. This ensures that the STA remains on the same subnet without breaking existing sessions ​.

A is true– MAC authentication often usesPAP or CHAPfor basic password exchange.

B is false– Bydefault, both theusername and password are set to the full MAC addressof the terminal, not just the last 6 digits.

C is true– MAC authentication istransparentto the user and requiresno client softwareon the terminal.

D is true– The authentication system includes:

Terminal(user device),

Access device(AP or switch), and

Authentication server(e.g., RADIUS).

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

“MAC authentication does not require client-side software. By default, both the user name and password are the complete MAC address in lowercase without delimiters.”

(Chapter: WLAN Security – Section: MAC Authentication Mechanism)

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 ​.

In RSTP, a port in thediscardingstate neither forwards data frames nor learns MAC addresses. A port in thelearningstate does not forward data frames but starts learning MAC addresses. Therefore, options A and B are correct, while C and D are incorrect due to misunderstandings of these states ​.

Comprehensive and Detailed In-Depth Explanation:

Type 7 LSAs (NSSA External LSAs)are used inNot-So-Stubby Areas (NSSAs)to carry external routing information.

These LSAs aregenerated only by ASBRs within an NSSA, and later converted toType 5 LSAsby theABR.

Stub areas do not allow ASBRs, meaningType 7 LSAs cannot exist in a stub area.

The question incorrectly states thatType 7 LSAs can be generated in stub areas, which isfalse.

📖Reference:Huawei HCIA-Datacom Study Guide, OSPF LSA Types and Area Configurations.

Comprehensive and Detailed In-Depth Explanation:

BFD (Bidirectional Forwarding Detection)detectslink failuresfaster than traditional mechanisms.

Session states during setup:

AdminDown→ Initial state (session is administratively disabled).

Down→ The session is being established but has not yet exchanged valid control packets.

Init→ The session is partially established (one side has detected the peer).

Up→ The session is fully operational (not part of the setup process).

SinceAdminDown, Down, and Initare involved insession setup, the correct answers areB, C, D.

📖Reference:Huawei HCIA-Datacom Study Guide, BFD Session Establishment and States.

A is correct– Confederations arespecifically designed for large-scale BGP deploymentswhere a full IBGP mesh is impractical.

B is correct– Sub-ASs within a confederation establishEBGP-like connectionsbetween each other but behave like IBGP within the overall AS. These sub-ASsdo not require full-mesh inside the confederation, but EBGP rules are followed between sub-ASs.

C is false–Not all devices need to be reconfigured. Devices within the same sub-AS retain normal IBGP behavior and minimal changes.

D is correct– Confederation istransparent to external peers, so thelogical topology remains the samefrom outside the AS.

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

“BGP confederation divides an AS into multiple sub-ASs. EBGP-like sessions are established between sub-ASs, while reducing IBGP mesh complexity. The external AS still sees the AS as one unit.”

(Chapter: BGP Scalability Enhancements – Section: Confederation)

Comprehensive and Detailed Step-by-Step Explanation:

BGP Router ID Selection Rules:

If a router ID is not manually configured:

The largest loopback address is selected as the router ID.

If no loopback interfaces exist, the largest active physical interface address is selected.

Default Behavior:

This ensures that a stable and unique router ID is chosen automatically, even without manual configuration.

The IPv6 address 2001:0DBB:B8:0000:C030:0000:0000:09A0:CDEF can be compressed by removing leading zeros in each segment and collapsing consecutive zero groups into ::. The result is 2001:DBB:B8:0:C030::9A0:CDEF ​.

Option A correctly configures the DHCP relay agent (AC) to forward requests to the DHCP server using VLAN 10.

Option B correctly configures the DHCP server (AR) with the correct IP pool (10.1.1.0/24), gateway, and excluded IP addresses. The static route to10.1.1.0through172.21.1.1ensures proper routing ​.

=========

The virtual MAC address for a VRRP virtual router is determined by the formula00-00-5E-00-01-[VRID in hexadecimal]. For VRID 3, the hexadecimal equivalent is03. Thus, the virtual MAC address is00-00-5E-00-01-03​.

Comprehensive and Detailed Step-by-Step Explanation:

STP and RSTP Behavior:

STP:Only thedesignated portprocesses inferior BPDUs. Inferior BPDUs are received from downstream switches and typically indicate topology changes.

RSTP:All ports, regardless of role (root, designated, or alternate), process inferior BPDUs to ensure faster convergence.

Behavior Difference:

RSTP improves convergence by allowing any port to process inferior BPDUs, unlike STP, which restricts this function to designated ports.

Comprehensive and Detailed Step-by-Step Explanation:

BGP Router ID Behavior:

The router ID uniquely identifies a BGP device in the network.

If the router ID is changed, it is equivalent to creating a new BGP instance, and the existing BGP session is reset to establish a new peer relationship.

Impact of Router ID Change:

BGP peering relies on stable identifiers. Changing the router ID disrupts the TCP session and requires reestablishing the relationship.

Comprehensive and Detailed In-Depth Explanation:

Spanning Tree Protocol (STP)haslong convergence timesdue toListening and Learning states.

Rapid Spanning Tree Protocol (RSTP)introduces:

Proposal/Agreement (P/A) mechanism→ Allows ports to quickly transition toForwarding statewithout waiting.

This mechanism significantlyreduces convergence timein aswitched network.

Since RSTPdoes use the P/A mechanismto accelerate port forwarding, the statement istrue.

📖Reference:Huawei HCIA-Datacom Study Guide, STP vs. RSTP and P/A Mechanism.

Comprehensive and Detailed Step-by-Step Explanation:

Routing Table Structure:

Routers maintain a localcore routing tableand separateprotocol routing tablesfor OSPF, BGP, etc.

The local core routing table storesoptimal routesselected based on metrics, protocol preferences, and administrative distances.

Fields in the Core Routing Table:

Destination Address (A):Indicates the destination network or host.

Routing Protocol Preference (B):Determines the priority of routing protocols (e.g., OSPF > RIP).

Routing Protocol (D):Specifies the protocol (e.g., OSPF, BGP) that contributed the route.

Inbound Interface:This is stored in the protocol-specific routing table but not in the local core table.

Comprehensive and Detailed Step-by-Step Explanation:

1. What is NETCONF?

NETCONF (Network Configuration Protocol) is an XML-based protocol used for network device configuration and management.

It enables reading, modifying, deleting, and restoring configurations programmatically.

2. Supported Operations:

Option A: Modifying configurations

Correct.

NETCONF allows you to modify existing configurations on network devices.

Option B: Deleting configurations

Correct.

Configurations can be deleted using NETCONF operations.

Option C: Restoring configurations

Correct.

NETCONF can restore configurations by applying previously saved configuration data.

Option D: Backing up configurations

Correct.

NETCONF can retrieve and save the current configuration as a backup.

3. Summary:

NETCONF supports all listed operations: modifying, deleting, restoring, and backing up configurations.

 R1 is a Level-1 router in Area 49.0001, while R4 is in Area 49.0004. Level-1 routers only maintain LSDBs for their own area and do not contain LSPs from other areas, such as R4’s LSP.

ï‚· R2 is a Level-1-2 router, so it maintains LSDBs for both Area 49.0001 (Level-1) and Level-2 domains, which include LSPs from R4.

ï‚· R3 and R4, as Level-2 routers, exchange LSPs with each other within the Level-2 domain.

 Thus, the LSDB of R1 does not include R4’s LSP ​.

An IP prefix filter is designed to match both the IP address and its prefix length, making it suitable for filtering routing information rather than data packets. Options A and D are incorrect because IP prefix filters do not work directly on data packets, and they can match both prefix numbers and lengths ​.

1 – Idle

2 – Connect

3 – OpenSent

4 – OpenConfirm

5 – Established

6 – Active

TheBGP finite state machinedefines how a BGP speaker transitions through various states when establishing and maintaining a BGP session. Below is the role of each state:

Idle (1)– BGP is waiting to start a connection. Initial state of the BGP process.

Connect (2)– BGP initiates a TCP connection to the peer.

OpenSent (3)– TCP connection is established; BGP sends an OPEN message and waits for one from the peer.

OpenConfirm (4)– BGP has received a valid OPEN message and is now expecting a KEEPALIVE.

Established (5)– BGP session is fully established; UPDATE messages can now be exchanged.

Active (6)– If the TCP connection fails in Connect state, BGP transitions to Active and will retry connection.

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

“BGP goes through the following states in order: Idle → Connect → Active → OpenSent → OpenConfirm → Established. The transition depends on the success or failure of TCP connection setup and BGP message exchanges.”

(Chapter: BGP Principles – Section: BGP State Machine)