H12-821_V1.0 Practice Exam Questions with Answers HCIP-Datacom-Core Technology V1.0 Certification

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:

IPsec (IP Security Protocol)establishesSecurity Associations (SAs)for encrypted communication.

AnSA is uniquely identified by a 3-tuple:

SPI (Security Parameter Index)? Identifies the SA.

Destination IP Address? Specifies the receiving device.

Security Protocol ID? Indicates whetherAH (Authentication Header) or ESP (Encapsulating Security Payload)is used.

A. Key exchange protocolisnotpart of theSA 3-tuple. It is used duringIKE (Internet Key Exchange)but is not part of the SA itself.

????Reference:Huawei HCIA-Datacom Study Guide, IPsec Security Association and SA Identification.

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.

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)

For first-time configuration of a newly purchased network device, administrators typically use the console port. This direct connection is secure and independent of network configuration, making it suitable for initial setups. Telnet, SNMP, or FTP require prior IP configuration, which is not feasible during the initial setup phase ?.

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."

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 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.

? IP Prefix List Matching Conditions

An IP prefix list matches based on:

Mask: Specifies the subnet mask length.

Action: Specifies whether to permit or deny.

Index: Orders the rules within the prefix list.

Port numbers are not applicable as matching conditions in an IP prefix list.

? HCIP-Datacom-Core Reference

IP prefix list configurations are detailed in the routing policy and route filtering chapters??.

? Transitive vs. Non-Transitive Attributes

The Community attribute is atransitive optional attribute, meaning that if a router receives a route with this attribute and does not understand its purpose, the router retains and propagates it to other peers.

Other options, such as AS_Path and MED, are well-defined mandatory or optional attributes with specific purposes.

? HCIP-Datacom-Core Reference

The behavior of optional transitive attributes is detailed in the BGP protocol and attribute chapters??.

Comprehensive and Detailed In-Depth Explanation:

Neighbor Discovery Protocol (NDP)replacesARP in IPv6and usesICMPv6 messagesfor:

Router Solicitation (RS)? Sent by hosts torequest Router Advertisement (RA) messages.

Router Advertisement (RA)? Sent by routers to announce prefixes and network parameters.

Neighbor Solicitation (NS)? Used foraddress resolutionandDuplicate Address Detection (DAD).

Neighbor Advertisement (NA)? Sent in response toNS messages.

Redirect? Used by routers toredirect hosts to better gateways.

RS is not directly used for address resolution;Neighbor Solicitation (NS) does this, so the answer should beD.

????Reference:Huawei HCIA-Datacom Study Guide, NDP and ICMPv6 Packet Types.

When a stack splits, the MAC addresses of the newly formed stacks do not change immediately. Instead, they retain their original MAC addresses until new ones are reassigned during topology updates. This delayed update prevents immediate conflicts and allows MAD (Multiple Active Detection) to handle any resulting issues ?.

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).

TheDHCPNAKmessage is sent by the DHCP server to the client to indicate that the requested configuration is not valid. Messages likeDHCPDiscover,DHCPRequest, andDHCPReleaseare initiated by the client in the DHCP process ?.

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??.

IGP routes can be injected into BGP using multiple methods, not just thenetworkcommand. Theimport-routecommand can also be used to redistribute IGP routes into BGP. Thenetworkcommand requires the route to exist in the routing table, whileimport-routeallows direct redistribution ?.

Goal Analysis:

Requirement:

The route to192.168.3.0/24must exist in R1's and R3's routing tables.

The route mustnot exist in R2's routing table.

This requires filtering to ensure the route is either:

Blocked on R2's routing table (via filtering on R2), or

Blocked before it is advertised to R2.

Analysis of Each Option:

Option A (Filter-policy on R2 for filtering received routes):

Applying a filter-policy on R2 to filter received routes will block the route from entering R2's routing table but still allow it to propagate to R3.

This meets the requirement.

Option B (Filter-policy on R2 for filtering the routes to be advertised):

Blocking the advertisement of routes from R2 to other routers does not affect the routes received by R2 itself.

This does not meet the requirement but does not affect the propagation to R3.

This is valid if the received route is blocked.

Option C (Filter-policy on R1 for filtering the routes to be imported):

If the route is filtered on R1 during the import phase, the route will not exist in R1’s routing table and thus cannot be advertised to either R2 or R3.

This fails to meet the requirement because the route must exist in R1's and R3's routing tables.

Option D (Filter-policy on R1 for filtering the imported routes to be advertised):

Filtering routes on R1 before advertising to R2 will prevent R2 from receiving the route but allow R1 to advertise the route to R3.

This meets the requirement.

Correct Option:

C (Filter-policy on R1 for filtering the routes to be imported):This will prevent the route from existing in both R1 and R3, violating the stated requirement.

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)

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.

The question indicates that a router performs a lookup in its FIB table for a packet and determines that the tunnel ID in the matching entry is 0, suggesting that the packet needs to be forwarded through a tunnel such as an MPLS tunnel. However, this is a misunderstanding of the FIB functionality.

FIB Table OverviewThe Forwarding Information Base (FIB) is used to make packet-forwarding decisions. Entries in the FIB include next-hop information, which can be directly linked to an interface or a tunnel.

If theTunnel IDis0, it indicates that the packet is forwarded via a normal routing path and not through a tunnel.

For MPLS or other tunnels, the Tunnel ID would have a non-zero value pointing to the associated tunnel.

MPLS Tunnel OperationWhen a router forwards packets through an MPLS tunnel, a label-switched path (LSP) is set up. The FIB would reflect specific tunnel identifiers for packets that need such encapsulation.

HCIP-Datacom-Core Reference

Routing Principles and MPLS?explain the forwarding mechanisms clearly, stating that if a packet is routed normally, the tunnel ID remains0.

The section on MPLS?clarifies the encapsulation process and the role of tunnel identifiers.

Hence, the claim in the question is incorrect. A Tunnel ID of0implies no tunneling is required, and normal IP forwarding occurs

LS Ack (Link State Acknowledgment) packets are used to acknowledge received LSAs and do not contain complete LSA information. Instead, they contain only the headers of LSAs being acknowledged. This contrasts with LS Update packets, which carry full LSA details. The misunderstanding of LS Ack functionality makes this statement false ?.

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?.

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 ?.

Comprehensive and Detailed Step-by-Step Explanation:

1. Overview of BFD Optimization:

BFD (Bidirectional Forwarding Detection) is a protocol that provides rapid detection of link failures.

Optimizing BFD involves adjusting parameters to balance between detection speed and network stability.

2. Analysis of Each Statement:

Option A: After a high priority is configured for BFD packets, BFD packets are preferentially forwarded.

Correct (True Statement).

High priority ensures that BFD packets are not delayed or dropped under congestion, improving detection accuracy.

Option B: To quickly learn about the network status and performance requirements, you can set the interval for sending BFD packets to the minimum value.

Incorrect (False Statement).

Setting the interval to the minimum value can lead to excessive BFD session flapping, which may overload the network or cause instability. The interval should be configured based on network requirements and conditions, rather than set to the minimum.

Option C: On a live network, some devices switch traffic only when a BFD session changes to the Up state... configure a delay to compensate for the time difference.

Correct (True Statement).

This is a valid optimization to avoid issues caused by timing mismatches between BFD and routing protocols.

Option D: If a BFD session flaps, master/backup switchovers are frequently performed... set the WTR time.

Correct (True Statement).

The WTR (Wait to Restore) timer helps stabilize BFD by delaying session recovery after a flap, reducing the risk of frequent switchovers.

3. Summary:

The false statement isB, as setting the BFD packet interval to the minimum can destabilize the network.

OSPF supports both area-level and interface-level authentication. When both are configured, interface authentication takes precedence over area authentication. This hierarchy ensures that specific interface-level configurations override the broader area-level settings when applicable ?.

The error indicates "Incorrect remote AS," which refers to a mismatch in the autonomous system (AS) numbers during BGP peer configuration. This issue is unrelated to the neighbor address. The neighbor address (10.1.1.5) and timestamp (2010-03-22 12:40:39) provided in the output are correct, and the error type confirms a neighbor relationship issue ?.

? BGP Open Message Components

The Open message contains the following critical parameters:

Local AS Number: The autonomous system of the router.

Router ID: A unique identifier for the router.

Hold Time: The maximum time the router will wait for Keepalive or other messages from its peer.

? Incorrect Option

C. NLRI: Network Layer Reachability Information is not included in Open messages; it is carried in Update messages.

? HCIP-Datacom-Core Reference

The structure and contents of Open messages are explained in BGP protocol details??.

IGMPv1 supports general queries but does not define a Leave message. IGMPv2 introduces the Leave message type, which allows hosts to notify routers when they wish to leave a multicast group, improving efficiency. These distinctions align with the functionality of IGMP versions ?.

A is false– Ports in MSTP can havedifferent roles and statesin different MSTIs. Each MSTI can independently elect a root and compute its own topology, which results indifferent port states per MSTI.

B is true– MSTIs use thesame spanning tree algorithm as STP (and RSTP)for calculating the spanning tree topology.

C is true– Each MSTI may have adifferent root bridgeand separate topology, depending on VLAN mappings.

D is true– MSTIs do not independently send BPDUs;only MSTI 0 (CIST)actually sends BPDUs, and information about other MSTIs is encapsulated within it. So thestatement is worded to test conceptual understanding, but not incorrect in MSTP context as framed.

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

“MSTP allows different MSTIs to have different topologies. A port may be forwarding in MSTI 1 but blocking in MSTI 2. This independence improves VLAN-based traffic engineering.”

(Chapter: MSTP Concepts – Section: MSTI Behavior and Port Roles)

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 ?.

Comprehensive and Detailed In-Depth Explanation:

A. TRUE? The interfaceGigabitEthernet0/0/1has anIP address of 192.168.1.1.

B. TRUE? TheIGMP version is explicitly stated as IGMPv2.

C. TRUE? Themaximum query response timefor IGMPis set to 10 seconds.

D. TRUE? TheIGMP Query Interval is configured as 60 seconds, meaning the routersends Group-Specific Queries every 60 seconds.

????Reference:Huawei HCIA-Datacom Study Guide, IGMP Configuration and Query Timers.

Comprehensive and Detailed Step-by-Step Explanation:

IPv4 Address Classes:

Class D:Reserved for multicast and defined by the first four bits as1110.

Address range:224.0.0.0 to 239.255.255.255.

Structure:

Class D does not include a network/host division, as it is designed for group communication rather than device identification.

If VRRP is not configured to track uplink interfaces, a failure in the master device's uplink or link will not trigger a switchover, resulting in a traffic blackhole. The VRRP mechanism relies on interface tracking to monitor connectivity and ensure role transitions upon faults. Without this configuration, no failover occurs, and traffic directed toward the master device is lost ?.

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 Step-by-Step Explanation:

1. Overview of AS_Path Attribute Modification:

The apply as-path command in a route-policy is used to modify the AS_Path attribute of routes. This is often required to influence the selection of routes or to adjust routing policies for incoming or outgoing BGP updates.

2. Parameters of the apply as-path Command:

Option A: Delete

Correct.

The delete parameter removes specific AS numbers from the AS_Path attribute. This is used to simplify or manipulate the AS_Path for specific routing policies.

Option B: Additive

Correct.

The additive parameter appends an AS number to the existing AS_Path attribute, instead of overwriting it. This is useful when you want to prepend AS numbers to influence route selection without removing the original AS_Path.

Option C: Copy

Incorrect.

The copy parameter is not supported in the apply as-path command for modifying AS_Path attributes.

Option D: Overwrite

Correct.

The overwrite parameter replaces the existing AS_Path with a new one. This provides complete control over the AS_Path attribute but removes the original AS_Path entirely.

3. Summary:

The valid parameters for the apply as-path command are delete, additive, and overwrite.

Huawei HCIA-Datacom Study Guide, Chapter "BGP Route Policies."

BGP Attribute Modification in Huawei Documentation.

Comprehensive and Detailed Step-by-Step Explanation:

1. Understanding the AS-Path Filter:

The as-path-filter command is used in BGP to filter routes based on the AS_PATH attribute.

In this configuration:

The filter si is defined with the regular expression _65500$.

The _65500$ expression specifies that the AS_PATH must end with 65500, meaning that the route's last hop must have passed through AS 65500.

2. Option Analysis:

Option A: It accepts only the routes whose AS_Path contains AS 65500.

Incorrect.

The _65500$ filter specifically matches routes where AS 65500 is the last AS in the AS_PATH. A route may contain AS 65500 somewhere in the middle of the AS_PATH but will not match this filter unless it is the last AS.

Option B: It accepts only the routes originated from AS 65500.

Incorrect.

Routes that originate from AS 65500 have an AS_PATH that starts with 65500. However, the filter _65500$ only matches routes where AS 65500 is the last AS, not the first AS.

Option C: It accepts only the routes that last pass through AS 65500.

Correct.

The _65500$ filter ensures that the AS_PATH ends with 65500. This means that the route must have last passed through AS 65500 before being received by the local BGP router.

Option D: It accepts only the routes forwarded by AS 65500.

Incorrect.

While AS 65500 may forward the route, this is not what the filter _65500$ specifically checks for. It only ensures that AS 65500 is the last AS in the AS_PATH.

3. Summary:

The as-path-filter with _65500$ accepts only the routes where AS 65500 is the last AS in the AS_PATH.

Huawei HCIA-Datacom Study Guide, Chapter "BGP Filtering Mechanisms"

RFC 4271: Border Gateway Protocol 4 (BGP-4)

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)

Comprehensive and Detailed Step-by-Step Explanation:

1. What is the BFD Echo Function?

BFD (Bidirectional Forwarding Detection) is used to detect link failures.

TheEcho functionis an optional feature that tests link connectivity by looping back packets sent from the local device through the forwarding path.

2. Analysis of Each Statement:

Option A: If URPF is enabled on the peer end, BFD packets may be incorrectly discarded on the peer end.

Correct.

URPF (Unicast Reverse Path Forwarding) checks whether the source IP address of an incoming packet is reachable via the interface it was received on. Since the Echo function uses loopback packets, this can conflict with URPF, causing the packets to be dropped.

Option B: In the BFD Echo function, the device uses the IP address of the outbound interface as the source IP address by default.

Correct.

By default, the outbound interface's IP address is used as the source address for BFD Echo packets.

Option C: The BFD Echo function applies only to single-hop BFD sessions.

Incorrect.

The BFD Echo function can be used for both single-hop and multi-hop BFD sessions.

Option D: When configuring a BFD session supporting the BFD Echo function, you need to configure both the local and remote discriminators.

Incorrect.

The BFD Echo function is locally configured and does not require setting remote discriminators. The function operates independently of the remote device's configuration.

3. Summary:

The correct statements areAandB.

Comprehensive and Detailed Step-by-Step Explanation:

1. What is L2TP (Layer 2 Tunneling Protocol)?

L2TP is a tunneling protocol used to transport Layer 2 frames over IP networks.

It is commonly used to establish VPNs but does not provide built-in encryption or security for the transmitted data.

2. Why L2TP Requires Additional Security Measures:

Since L2TP does not encrypt traffic, it is vulnerable to eavesdropping and tampering.

To secure L2TP tunnels, it is often paired with IPsec, which provides strong encryption and authentication. The combination of L2TP and IPsec is known asL2TP/IPsec.

3. Why the Statement is TRUE:

The statement accurately describes the limitation of L2TP (lack of encryption) and the need for additional security measures like IPsec.

Comprehensive and Detailed Step-by-Step Explanation:

1. Overview of BGP:

BGP (Border Gateway Protocol) is an Exterior Gateway Protocol (EGP) designed to exchange routing information between different Autonomous Systems (ASs) on the internet. Unlike traditional distance-vector protocols (like RIP), BGP is considered a path-vector protocol, as it not only determines reachability but also ensures policy-based routing decisions and advanced path selection mechanisms.

2. Analysis of Each Option:

Option A: BGP does not support authentication. Therefore, it cannot ensure network security.

This statement isincorrect.

BGP supports authentication using mechanisms such as TCP MD5 (Message Digest 5) and TCP-AO (Authentication Option). These authentication mechanisms ensure that BGP messages are not tampered with or intercepted during transmission, enhancing network security.

HCIA-Datacom Study Guide, Chapter "BGP Concepts and Features," Authentication Section.

Option B: BGP uses TCP as the transport layer protocol.

This statement iscorrect.

BGP relies on TCP (Transmission Control Protocol) as its transport layer protocol, specifically on port 179. TCP provides reliable delivery of BGP messages and ensures the session remains established in case of transient network issues.

TCP also handles error recovery and sequencing, making it a suitable choice for BGP, which requires reliable communication between peers.

Comprehensive and Detailed In-Depth Explanation:

Intermediate System to Intermediate System (IS-IS)routers sendIS-to-IS Hello (IIH) packetsto establish neighbor relationships.

TheReserved/Circuit Type fieldin IIH packets indicateswhich level of IS-IS adjacencythe router is trying to establish:

00? Level-0 (Not used in IS-IS).

01? Level-1 router.

10? Level-2 router.

11?Level-1-2 router (Both levels supported).

Since the question asks for the field value in anL1-L2 router’s IIH packets, the correct answer is11 (B).

????Reference:Huawei HCIA-Datacom Study Guide, IS-IS Neighbor Discovery and IIH Packet Format.

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.

Explanation of IS-IS Packet Types and Synchronization Process:

In the given scenario, R2 requests LSPs from R1 to synchronize its Link State Database (LSDB). The following IS-IS packet types are involved in this synchronization process:

1. P2P IIH (Point-to-Point IS-IS Hello):

Purpose:Establishes and maintains IS-IS neighbor relationships.

Step:This packet is exchanged initially to detect and maintain the adjacency between R1 and R2.

2. PSNP (Partial Sequence Number PDU):

Purpose:Requests missing or outdated LSPs (Link State PDUs) from a neighbor to synchronize the LSDB.

Step:In this case, R2 sends a PSNP to R1 to request the missing or outdated LSP.

3. LSP (Link State PDU):

Purpose:Contains routing information and is used to update the LSDB.

Step:R1 sends the requested LSPs to R2 for synchronization.

4. CSNP (Complete Sequence Number PDU):

Purpose:Lists all LSPs in the sender's LSDB to help neighbors verify and request missing LSPs.

Step:R1 sends a CSNP during retransmission timeout to notify R2 of its LSPs.

In a route-policy, attributes such asMED(Multi-Exit Discriminator) andLocal-Preferencecan be used in apply clauses to influence BGP route selection. Attributes likeAS_PathandTagare typically matched or filtered but not directly applied in the apply clause ?.

Thesummary automaticcommand in BGP is used to enable automatic summarization of routes, particularly for classful networks. However, manual summarization takes precedence over automatic summarization when both are configured. This makes the statement claiming automatic summarization takes precedence false ?.

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.

? Link fault alarm

? The BFD session goes down.

? Interrupted OSPF neighbor relationship

OptionA is false. When advertising a route to an IBGP peer, theBGP speaker does not modifythe AS_Path. It simply advertises the routeas-is, preserving the AS_Path learned from EBGP.

Clarification of the options:

Bis correct: When a route is sent to an EBGP peer, the local AS is prepended to the AS_Path.

Cis correct: The AS_Path begins with the local AS when a new route is advertised to an EBGP neighbor.

Dis correct: IBGP doesnotmodify AS_Path when passing routes within the same AS.

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

“BGP speakers prepend their AS number to the AS_Path only when advertising to EBGP peers. IBGP peers do not alter the AS_Path.”

(Chapter: BGP Path Attributes – Section: AS_Path)

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)

? 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??.

Comprehensive and Detailed In-Depth Explanation:

A. TRUE? EBGP-learned routescan be advertised to both IBGP and EBGP peers.

B. FALSE?BGP uses incremental updates, meaning itonly advertises changed routes, not all routes.

C. TRUE?BGP advertises only the best pathto prevent unnecessary routing information.

D. TRUE?IBGP split-horizon rule: Routeslearned from IBGP peers are not re-advertised to other IBGP peers(to prevent loops).

????Reference:Huawei HCIA-Datacom Study Guide, BGP Route Advertisement and Split-Horizon Rule.

When routes are imported into BGP using theimport-routecommand, the origin attribute is set toincompleteby default. This indicates that the route's origin is not known or is from an external source, as opposed to being explicitly learned through an IGP (IGP) or EGP (EGP) protocol ?.

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 ?.

? pat

? trust

? 12.1.1.0

? inner

Comprehensive and Detailed Step-by-Step Explanation:

1. BGP Attributes Overview:

BGP uses attributes to describe the properties of routes. These attributes are classified into the following categories:

Well-Known Mandatory: Attributes that must be recognized and included in every BGP update. Examples: AS_PATH, ORIGIN, NEXT_HOP.

Well-Known Discretionary: Attributes that must be recognized but are not required in every BGP update. Examples: LOCAL_PREF, ATOMIC_AGGREGATE.

Optional Transitive: Attributes that may or may not be recognized, but must be passed along to other BGP peers. Examples: COMMUNITY.

Optional Non-Transitive: Attributes that may or may not be recognized, and are not passed along to other BGP peers. Examples: MED (Multi-Exit Discriminator).

2. Analysis of Each Option:

Option A: Atomic_Aggregate

Correct.

This is a well-known discretionary attribute. It indicates that the advertised route is an aggregate route that summarizes multiple specific routes.

Option B: Local-Preference

Correct.

This is a well-known discretionary attribute. It is used within an AS to prioritize routes, with higher values being preferred.

Option C: Community

Incorrect.

The COMMUNITY attribute is an optional transitive attribute. It is used to tag routes with specific labels to apply routing policies.

Option D: MED (Multi-Exit Discriminator)

Incorrect.

The MED attribute is an optional non-transitive attribute. It is used to influence the choice of the preferred path when there are multiple entry points into an AS.

3. Summary:

Well-Known Discretionary Attributes: Atomic_Aggregate and Local-Preference.

Huawei HCIA-Datacom Study Guide, Chapter "BGP Route Attributes."

RFC 4271: Border Gateway Protocol 4 (BGP-4).

The preference of routing protocols determines the selection order of routes when a router receives multiple routes to the same destination from different routing protocols. For instance, OSPF has a higher preference over RIP, so OSPF routes will be selected first. Huawei routing preferences confirm this behavior ?.

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 Step-by-Step Explanation:

To answer this question, we need to understand the roles of OSPF routers:

Area Border Router (ABR):

An ABR is a router that connects multiple OSPF areas. It has at least one interface in the backbone area (Area 0) and one or more interfaces in other OSPF areas.

The ABR performs summarization between areas and propagates routing information between them.

Backup Router (BR):

The term "BR" does not exist in OSPF terminology. Instead, OSPF uses the term "Backup Designated Router (BDR)." The BDR is a backup to the Designated Router (DR) in a specific OSPF broadcast or NBMA (Non-Broadcast Multi-Access) network. The BDR takes over the DR's responsibilities if the DR fails.

Key Clarification:

An ABR is related to the hierarchical structure of OSPF areas and is not tied to the DR/BDR election process.

A router can function as an ABR without ever being a DR or BDR, as these are separate roles.

Therefore, the statement that an ABR must also be a BR isFALSE.

? Non-Client Definition in IBGP

In an IBGP setup with a Route Reflector (RR), a non-client is an IBGP peer that is neither the RR itself nor its client.

Non-clients must establish fully meshed IBGP connections with all other non-clients and the RR because IBGP rules prohibit route propagation between non-clients without a direct connection.

? HCIP-Datacom-Core Reference

The behavior of non-clients in an RR topology is clearly outlined in the BGP implementation chapters??.

The monitoring plane's primary role is environmental monitoring, ensuring the stability of the system. Functions like voltage monitoring, temperature tracking, fan speed control, and power management are standard. These are independent of the forwarding or control planes and critical for maintaining device health in network operations ?.

DIS Election in IS-IS:

In IS-IS, theDesignated Intermediate System (DIS)is elected on broadcast networks to reduce the number of LSAs exchanged and maintain the LSDB.

The DIS is elected based onpriority:

The router with thehighest priorityis elected as the DIS.

If priorities are equal, theSystem IDis used as a tie-breaker, and the router with thehighest System IDbecomes the DIS.

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

Given DIS Priorities:

R1: Priority = 10

R2: Priority = 20

R3: Priority = 30

R4: Priority = 40

R4 has the highest DIS priority of 40, which makes it the clear choice for DIS election.

Scenario Details:

Since all devices are started simultaneously, the DIS election process will follow the priorities without requiring a tie-breaker (System ID).

Conclusion:

The device with the highest DIS priority isR4, and it will be elected as the DIS.

? Permanent Group Addresses for Routing Protocols

The range224.0.0.0 to 224.0.0.255is reserved for local network protocols, including routing protocols. Examples include OSPF (224.0.0.5/6) and RIP (224.0.0.9).

? HCIP-Datacom-Core Reference

Reserved multicast address ranges are detailed in the multicast configuration sections??.

Comprehensive and Detailed In-Depth Explanation:

BGP does not support automatic summarization for IPv6 networks.

InIPv4, BGP could performautomatic summarizationatclassful boundaries, but this feature isnot supported for IPv6.

Manual summarizationcan be configured usingaggregate IPv6 addresses(e.g., using the aggregate-address command).

Since the statement incorrectly claims thatBGP supports automatic summarization for IPv6, it isfalse.

????Reference:Huawei HCIA-Datacom Study Guide, BGP Route Summarization for IPv4 and IPv6.

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.

Let’s analyze the process step-by-step:

R1redistributes thedirect route 10.1.1.0/24intoOSPF.

This OSPF route reachesR2andR3.

R2 and R3 are in an environment that usesIS-IStowardsR4.

BothR2 and R3 re-advertisethis OSPF route into IS-IS toward R4 (bidirectional route redistribution).

OnR3, aroute-policy named hcipis applied to controlASE (Autonomous System External) route preference.

The ACL matches the route10.1.1.0/24.

The route-policy sets thepreferenceof this ASE route to14.

InHuawei VRP, if a route-policy applied via preference ase route-policy matches a route, itmodifies the preferencevalue of the redistributed route when it is advertised.

By default:

OSPF ASE routeshave apreference of 150.

But in this case, due to the policy applied, the preference is explicitly changed to14on R3 before re-advertising to R4.

So,R4will install the route10.1.1.0/24from R3 withpreference 14, assuming R2 doesn’t provide a better preference.

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

“You can control the preference of OSPF ASE routes by using a route-policy and applying it with the command preference ase route-policy. When the policy matches, the specified preference is used instead of the default (150).”

(Chapter: OSPF Advanced Features – Section: Route Control and Inter-AS Route Redistribution)

Comprehensive and Detailed Step-by-Step Explanation:

Bidirectional Forwarding Detection (BFD):

BFD is a lightweight protocol that provides rapid fault detection on links independent of the underlying routing protocol or media.

Requirements for BFD:

Both devices at the endpoints of the link must support and configure BFD for it to operate.

If one device does not support BFD, the feature cannot be used for link detection.

Secure access channels include protocols that encrypt the transmitted data to protect against interception or unauthorized access. HTTPS (HyperText Transfer Protocol Secure) ensures data encryption over web communications, while SFTP (Secure File Transfer Protocol) provides secure file transfer by utilizing SSH for data encryption. Telnet and SNMPv2, on the other hand, lack robust encryption and are considered insecure. Huawei security standards highlight the importance of encrypted communication to prevent data leaks ?.

In the PIM protocol,Register StopandGraftmessages are sent with unicast destination addresses, typically to specific neighbors or RP (Rendezvous Point) routers. Other messages likeBootstrapandAssertuse multicast addresses for broader dissemination across the network ?.

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 ?.

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??.

OSPF process IDs are locally significant and do not need to match between routers to form neighbor relationships. The other statements correctly describe the behavior of OSPF multi-instances, making Option C false ?.

Attributes such ascommunity,tag, andorigincan be directly referenced in theapplyclause of a route-policy. However,IP-prefixis not an attribute but a prefix list used for matching, and it cannot be directly applied ?.

When the router ID is configured in both the system view and the BGP view, the router ID in the BGP view takes precedence because BGP-specific configurations override global settings. This ensures that BGP operates with the most relevant configurations ?.

Comprehensive and Detailed Step-by-Step Explanation:

IS-IS Three-Way Handshake:

IS-IS uses athree-way handshaketo establish neighbor relationships.

This process is applied on bothpoint-to-point (P2P)andbroadcastnetwork types to confirm bidirectional communication.

P2P Networks:

Routers directly exchange IS-IS Hello (IIH) packets to establish adjacency.

Broadcast Networks:

IS-IS also uses the three-way handshake on broadcast networks to ensure that the Designated Intermediate System (DIS) election and adjacency formation are correct.

VRRP defines the following states:Initialize– The router is starting up or has not joined a VRRP group.Backup– The router is in standby and monitors the Master.Master– Theonly statewhere the deviceforwards trafficfor thevirtual IP address.Only the router in theMasterstate owns the virtual MAC and responds to ARP for the virtual IP.Reference from Huawei HCIP-Datacom-Core Technology Study Guide:“In VRRP, only the Master forwards packets destined for the virtual IP address. Backup routers take over only if the Master fails.”(Chapter: VRRP Concepts – Section: State Roles and Transitions)

Option B isfalse. By default, when the aggregate command is usedwithout any options, BGP generates asummary route, andsuppresses the specific routesthat fall under that summary. To advertise both specific and summary routes, you mustexplicitly configurethe detail-suppressed option to control whether specifics are suppressed or not.

Explanation of the other options:

Ais correct: When suppress-policy is specified, only specific routes matching the policy are advertised; others are suppressed.

Cis correct: The summary automatic command causes summarization based on classful boundaries, which is a legacy behavior.

Dis correct: With detail-suppressed, only the summary route is advertised, not specific prefixes.

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

“The aggregate command suppresses specific routes by default unless explicitly configured otherwise. Use of suppress-policy or detail-suppressed allows control over which routes are advertised.”

(Chapter: BGP Advanced Features – Section: Route Aggregation)

Comprehensive and Detailed In-Depth Explanation:

BGP uses TCP (not UDP) on port 179to establish peer relationships.

Peer IP must be routableinboth IBGP and EBGP, butBGP does not use UDP connections.

The statement isfalsebecause of theincorrect mention of UDP.

????Reference:Huawei HCIA-Datacom Study Guide, BGP Session Establishment and TCP Usage.

BGP does not advertise all routes learned from peers to other peers. By default, only the best (optimal) routes selected by BGP are advertised to other peers. Additionally, routes learned from IBGP peers are not forwarded to other IBGP peers unless a route reflector or confederation setup is used. The statement claiming all learned routes are advertised is false ?.

Comprehensive and Detailed In-Depth Explanation:

OSPF-to-BGP route redistributiondoesnot allow modification of MED valuesdirectly using aroute-policyin Huawei devices.

Instead,MED can be set using a BGP attribute policy, not through the import command.

All other options (B, C, D) are correct:

B? Route-policycan filter imported direct routes.

C? network commanddoes not modify attributes, only announces existing routes.

D? peer commandcan set Local Preferencevia route-policy.

????Reference:Huawei HCIA-Datacom Study Guide, BGP Route Policy and Attribute Modification.

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 Explanation:

Internal Router (IR): A router that exists entirely within asingle OSPF area(e.g., Area 0). It doesnot have to be a Border Router (BR).

Area Border Router (ABR): A router that connectstwo or more OSPF areas. It maintains separate LSDBs for each area and forwardssummary LSAsbetween them.

Autonomous System Boundary Router (ASBR): A router that connects the OSPF domain to anexternal network(e.g., BGP, another OSPF AS).

The statement isfalsebecause:

AnIR in Area 0 does not have to be a BR(Border Router). It can just be a normal internal router.

AnASBR does not have to be an ABR. An ASBR can existinside any OSPF area, even a single area, without needing to connect multiple areas.

????Reference:Huawei HCIA-Datacom Study Guide, OSPF Router Types and Area Concepts.

In inter-AC roaming scenarios, an AC (Access Controller) can serve as the mobility server for multiple mobility groups, enabling it to manage roaming among multiple groups. However, an AC can only belong to one specific mobility group. This constraint ensures that mobility management remains streamlined and avoids conflicts. Huawei WLAN mobility configuration guides validate this setup ?.

Comprehensive and Detailed Step-by-Step Explanation:

Distance-Vector Protocols:

Distance-vector protocols determine the best path based on the distance to a destination and periodically share the entire routing table with neighbors.

Example:RIPis a distance-vector protocol.

Link-State Protocols:

Link-state protocols share information about directly connected links, enabling routers to build a complete map of the network.

OSPF(Open Shortest Path First) andIS-IS(Intermediate System to Intermediate System) are link-state protocols that use Dijkstra’s algorithm to calculate the shortest path.

Border Gateway Protocol (BGP):

BGP is neither a distance-vector nor a link-state protocol. Instead, it is classified as apath-vector protocolthat selects the best path based on attributes such as AS-path, next-hop, and local preference.

? 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.

? HCIP-Datacom-Core Reference

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

Comprehensive and Detailed In-Depth Explanation:

NET (Network Entity Title)is a special form ofNSAP (Network Service Access Point)used inIS-IS routing.

NET consists of three fields:

AFI (Authority and Format Identifier) + IDI (Initial Domain Identifier) + Area Address? Identifies thearea.

System ID? Uniquely identifies arouter within an area(similar to an OSPF Router ID).

SEL (NSEL - N-selector)? Always0in a NET, as IS-IS operates at Layer 3.

SinceSystem IDuniquely identifies ahost/router within an area, the correct answer isA.

????Reference:Huawei HCIA-Datacom Study Guide, IS-IS Addressing and NET Structure.

? DIS and DR Election

The IS-IS Designated Intermediate System (DIS) is responsible for generating and updating pseudonode LSPs on a broadcast network.

Unlike OSPF DR, the IS-IS DIS does not preempt by default. This behavior avoids unnecessary flapping in the network due to frequent DIS re-elections.

? HCIP-Datacom-Core Reference

The characteristics of DIS and DR behavior are explained in IS-IS network operation chapters??.

IGMP Version Mismatch

If the IGMP snooping version on the device is earlier than the IGMP version on user hosts, the device may fail to parse IGMP Report messages correctly. As a result, the device forwards these messages only to router ports without generating group member ports or forwarding entries.

Consequently, users cannot receive multicast data.

HCIP-Datacom-Core Reference

Multicast and IGMP snooping behaviors under mismatched conditions are described in the multicast configuration chapters??.

When OSPF routers exchange LSDBs using Database Description (DD) packets, they first establish a master-slave relationship. The router with the larger Router ID becomes the master, setting the MS (Master/Slave) bit in the DD packets. This hierarchical relationship ensures an orderly exchange of routing information ?.

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 Step-by-Step Explanation:

Switch Stack Overview:

In a switch stack, roles are assigned asmaster,standby, andslave.

The master handles configuration and control, while the standby serves as the backup master.

Behavior During Master Restart:

D:If the master switch restarts, the standby switch immediately takes over as the new master.

B:After the original master switch restarts, it becomes the master again (default behavior).

Incorrect Options:

A:The slave switch is not promoted to standby before the master switch restart completes.

C:The original standby switch remains the master after the restart.

GRE (Generic Routing Encapsulation) is not a Layer 2 VPN technology. Instead, it is a Layer 3 tunneling protocol used to encapsulate a wide variety of network layer protocols inside point-to-point connections. GRE is commonly used for creating VPN tunnels across IP networks,allowing for the transport of various types of payloads. This misunderstanding about GRE being a Layer 2 technology contradicts its definition and typical application ?.

? 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.

? Incorrect Option

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

? HCIP-Datacom-Core Reference

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

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.