Huawei H12-811_V2.0 HCIA-Datacom V2.0 Exam Practice Test

All four statements are correct. The code uses the Paramiko library to automate SSH login to a network device. import paramiko and import time load the Python modules required for SSH communication and delay control, so option C is correct. The statement ssh = paramiko.SSHClient() creates an SSH client object, and ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy()) allows the client to accept an unknown host key automatically in this example scenario.

The command ssh.connect( ' 192.168.1.254 ' , username= ' python ' , password= ' Huawei@123 ' ) establishes an SSH connection to the target device, so option B is correct. Then channel = ssh.invoke_shell() opens an interactive shell channel , which is commonly used to send CLI commands and receive output just as an administrator would in a terminal session, making option D correct. The command channel.send( ' screen-length 0 temporary\n ' ) disables page-by-page output for the current session, which is useful in network automation. Finally, ssh.close() closes the SSH session and releases the connection, so option A is correct. HCIA-Datacom automation knowledge often uses Paramiko examples to demonstrate basic Python-based device O & M.

OSPF divides a large routing domain into areas so that link-state information can be contained and the processing burden on individual routers can be reduced. Within a given OSPF area, routers exchange LSAs and synchronize the area ' s link-state database. After the network has converged and the participating routers have full adjacency where required, routers in the same area maintain a consistent view of that area ' s topology. Each router then runs the SPF algorithm independently against that common LSDB, using itself as the root, so the calculated shortest-path tree can differ in perspective even though the underlying area topology database is the same. Area boundaries also limit which detailed LSAs need to be maintained by routers outside the area, which is one reason hierarchical OSPF scales better than a single very large area. The statement should be understood under normal, converged OSPF operation; simply sharing an area number without connectivity would not create synchronization. In the intended HCIA Datacom context, R1 and R2 participating in the same area maintain the same area LSDB. Therefore the answer is TRUE, option A.

Huawei uses DHCP Option 148 for IPv4-based plug-and-play or zero-touch deployment of devices to iMaster NCE-Campus. The DHCP server can include controller information in this vendor-specific option, allowing a switch, router, or cloud-managed AP to obtain the southbound address or URL of iMaster NCE-Campus together with the required management port. After the device receives normal addressing information and the Option 148 parameters, it can reach the controller and establish the management channel, including NETCONF-based management in supported deployment scenarios. Huawei documentation distinguishes this from IPv6 deployment, where Option 17 can be used for equivalent controller discovery. The Option 148 value commonly carries fields such as the controller management mode, domain or IP address, and management port. This removes the need to manually enter controller information on every new device and is widely used in iMaster NCE- Campus onboarding workflows. Therefore, the numeric value required in the blank is 148, matching the source answer and Huawei campus deployment documentation.

A /28 subnet mask corresponds to 255.255.255.240, which means each subnet contains 16 IP addresses . The subnet boundaries in the last octet increase in steps of 16: 0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, and so on. The host address 192.168.1.147 falls within the subnet range 192.168.1.144 to 192.168.1.159 .

In that subnet, the network address is 192.168.1.144, the usable host range is 192.168.1.145 through 192.168.1.158, and the broadcast address is 192.168.1.159. Therefore, option C is correct. Option D is the first usable host address, not the broadcast address. Option A is just another usable host address. Option B would be the broadcast address only for a /24 network, not for a /28. HCIA-Datacom requires learners to master subnetting because it is essential for IP planning, gateway deployment, route summarization, and troubleshooting Layer 3 communication issues in campus and enterprise networks.

This statement is false . In classic STP, when a non-root switch detects a topology change, it does not continuously send configuration BPDUs upstream to notify the root bridge. Instead, it sends a Topology Change Notification (TCN) BPDU toward the root bridge through its root port. Each upstream switch acknowledges the TCN and forwards it further until it reaches the root bridge.

After the root bridge receives the topology change notification, the root bridge sets the Topology Change (TC) flag in its configuration BPDUs, and those configuration BPDUs are then propagated throughout the network. Therefore, topology-change notification and normal configuration BPDU transmission are different functions. The statement is wrong because it confuses TCN BPDUs with configuration BPDUs , and also inaccurately describes the notification behavior. HCIA-Datacom requires learners to distinguish between these BPDU types and understand how STP reacts to topology changes by accelerating MAC address aging and informing the network through the root bridge. This process helps the Layer 2 topology converge and reduces long-lasting forwarding inconsistencies after a link or port-state change.

Option D is correct. The AAA configuration binds the domain huawei.com to the authentication scheme auth1 , which uses RADIUS as the authentication mode, and to the accounting scheme acc1 , which also uses RADIUS. Therefore, when a user logs in with a user name in the format hcia-datacom@huawei.com , the device parses the suffix @huawei.com, matches the domain, and applies the configured RADIUS authentication method.

Option A is false because RADIUS does support accounting , and UDP port 1813 is commonly used for that purpose. Option B is false because a separate authorization server IP is not strictly required in this context; RADIUS can carry authorization attributes together with authentication/accounting processing depending on server behavior and device configuration. Option C is false because standard RADIUS communication uses UDP , not TCP, with authentication typically on port 1812 and accounting on 1813 . HCIA-Datacom teaches domain-based AAA processing as a key concept, where the user name suffix determines which authentication, authorization, and accounting policies are applied on the NAS device.

This statement is true . ARP is a Layer 2 broadcast-based protocol used to resolve an IPv4 address into a MAC address within the same broadcast domain. If two PCs are connected to the same switch but cannot learn each other’s ARP entries, one likely reason is an incorrect VLAN configuration .

For example, if PC1 and PC2 are placed in different VLANs, or if one interface is configured with the wrong access VLAN, ARP broadcast frames from one PC will not reach the other PC because VLANs separate Layer 2 broadcast domains. As a result, the ARP request will not be received by the peer, and the MAC address cannot be resolved. Other causes may also exist, such as incorrect IP addressing, port isolation, or security policies, but VLAN misconfiguration is a very common and valid cause in campus switching scenarios. HCIA-Datacom teaches that ARP communication depends on correct Layer 2 domain membership, and VLAN planning or interface configuration errors often directly affect host-to-host communication even when both hosts are physically connected to the same switch.

A Fat AP integrates both wireless access functions and the control or management functions needed to provide WLAN service. It can therefore operate independently without a separate wireless access controller (WAC). This architecture is practical for small deployments in which only a few APs are required and centralized policy control, large-scale roaming optimization, and unified configuration are not major requirements. Typical examples include homes, small offices, and small retail locations. In contrast, a Fit AP is designed to work under a WAC, with many management and control functions centralized on the controller. That model scales better for enterprise and campus networks containing many APs. Huawei also supports cloud-managed designs in which management functions are provided through a cloud or controller platform, but that does not change the fundamental distinction between traditional Fat and Fit architectures. Because the question states that a Fat AP can provide user access without being managed by a WAC and is suitable for small scenarios, the statement accurately describes the Fat AP model. The correct answer is TRUE, option A.

All four addresses can successfully ping 10.0.23.3, so the correct answer is A, B, C, D .

The key point is that the traffic policy is applied outbound on GE0/0/1 of R1, which is the interface facing S1 . When S1 pings 10.0.23.3, the echo request travels from S1 to R1 and then to S2. The return echo reply from 10.0.23.3 comes back to R1 and is then sent outbound on GE0/0/1 toward S1. Therefore, the traffic policy examines the reply packets , not the original ping request packets.

In those reply packets, the source IP address is 10.0.23.3 , and the destination is one of S1’s loopback addresses. The ACL rules denying 10.0.1.1 and 10.1.1.1 as source addresses do not match these reply packets, because those addresses appear as destination addresses , not source addresses. In addition, the ACL contains rule permit ip, which permits all remaining IP traffic. As a result, replies to all four S1 addresses are forwarded successfully, so every listed address can ping 10.0.23.3.

During modulation, the transmitter maps digital information onto certain physical characteristics of a carrier signal so that the information can be transmitted over the air. The three classic carrier parameters that can be modified are amplitude , frequency , and phase . Therefore, options A , B , and D are correct.

Amplitude modulation changes the strength of the carrier wave. Frequency modulation changes the oscillation rate of the carrier. Phase modulation changes the phase angle of the carrier relative to a reference. Modern wireless communication systems often combine these parameters, especially amplitude and phase, in complex digital modulation schemes such as QPSK, 16-QAM, 64-QAM, or higher-order QAM used in WLAN standards. Option C , channel, is not a carrier parameter modified during modulation. A channel refers to a frequency resource or spectrum allocation used for communication, not a physical waveform characteristic being directly altered to encode bits. HCIA-Datacom introduces these basic wireless concepts to help learners understand how WLAN signals are transmitted, how data rate improvements are achieved, and why different modulation methods have different requirements for signal quality and interference resistance.

All four options are possible causes of FTP login failure, so the correct answer is A, B, C, and D.

Option A is correct because if the FTP server function is not enabled on the Huawei device, the device cannot provide FTP services and the client cannot log in. Option B is also correct because if the authorized directory is not specified for the FTP user, the user may not be able to complete login or access file services properly, depending on the FTP user configuration requirements. Option C is correct because an FTP user account must be configured with the required username and password; otherwise, authentication cannot succeed. Option D is also correct because if the network between the FTP client and the device is unreachable, the client cannot establish the FTP connection at all.

In HCIA-Datacom troubleshooting, FTP login failure is usually checked from four aspects: service enablement, user configuration, permission or directory authorization, and network connectivity. This question tests standard remote maintenance troubleshooting logic for file transfer services on Huawei network devices.

The correct answer is C. In the command output, the AP state is shown as ver-mismatch. This state directly indicates a version mismatch between the AP and the WAC. In Huawei WLAN deployment, a Fit AP must use a software version that is compatible with the WAC version. If the versions do not match, the AP may be discovered by the WAC and appear in the AP list, but it cannot successfully complete the online process.

Option A is incorrect because blacklist-related failures are displayed with blacklist-related status information, not ver-mismatch. Option B is also incorrect because authentication failures normally generate authentication-related fault indications. Option D is incorrect because configuration initialization failure would not be identified by the specific ver-mismatch state.

HCIA-Datacom troubleshooting knowledge emphasizes reading AP online states carefully. Common causes of AP online failure include IP address acquisition failure, CAPWAP tunnel establishment failure, insufficient licenses, authentication problems, and version mismatch. When the state explicitly shows ver-mismatch, the troubleshooting direction is clear: check AP and WAC software compatibility and upgrade or align the software version as needed.

Several upper-layer management and file transfer protocols use SSH as their secure transport foundation. SFTP is the SSH File Transfer Protocol and operates over SSH, making option C correct. STelnet is secure Telnet implemented over SSH, so option D is also correct. NETCONF commonly uses SSH as its transport protocol for secure configuration management and device orchestration, making option B correct as well.

Option A, DNS, does not use SSH as its normal transport protocol. Traditional DNS operates over UDP or TCP port 53, depending on the query or transfer type. Although DNS security extensions and encrypted DNS variants exist, they are not based on SSH. HCIA-Datacom emphasizes the role of SSH in secure network management because it replaces insecure plaintext protocols and provides confidentiality, integrity, and authentication. In practical Huawei enterprise deployments, SSH-based protocols are widely used for interactive device login, automated configuration delivery, and secure file operations. This question tests recognition of management protocols that inherit SSH’s secure channel rather than protocols that operate independently at the application layer.

The source key marks this statement TRUE, but the topology makes that answer technically incorrect. R1 is shown with interface address 10.0.12.1/24, which automatically installs a directly connected route to 10.0.12.0/24. On Huawei VRP, a direct route has preference 0, whereas a static route has preference 60 unless another value is configured. The two commands do configure two static routes with the same preference, and equal-preference static routes can support load balancing when they are the best routes to a destination. Here, however, both static routes are for the same prefix that R1 already owns as a connected network. The direct route has a higher priority because its preference value is smaller, so it is selected in the active IP routing table instead of the two preference-60 static routes. Therefore the assertion that R1 has two active equal-cost routes to 10.0.12.0/24 is FALSE as the question and exhibit are written. The verified answer is B, and the original source key A should be corrected.

The IPv6 basic header has a fixed length of 40 bytes and contains eight fields: Version, Traffic Class, Flow Label, Payload Length, Next Header, Hop Limit, Source Address, and Destination Address. The Source IPv6 Address is therefore part of the IPv6 header. Hop Limit is also present and serves a function comparable to the IPv4 TTL field by limiting how many Layer 3 forwarding hops a packet can traverse. Next Header identifies the type of extension header or upper-layer protocol that follows the IPv6 basic header. A source MAC address is not part of the IPv6 header. MAC addresses belong to the data-link-layer frame header, such as an Ethernet header, and are relevant only to the current Layer 2 segment. As an IPv6 packet is routed, Ethernet source and destination MAC addresses can change from hop to hop while the IPv6 source and destination addresses normally remain unchanged end to end. Therefore A, B, and C are IPv6 header fields, while D is not. The correct answer is A, B, and C.

After STP convergence, only ports in the forwarding state participate in active traffic forwarding, while redundant ports may be placed into the blocking or discarding state to eliminate loops. According to the topology and STP role election shown in the question, the valid forwarding path from SW1 to SW4 is SW1 → SW3 → SW4, so option B is correct.

This means that the direct alternative path or the path through SW2 is not the active spanning-tree forwarding path after election and state transition. STP selects paths based on the root bridge, path cost, bridge ID, and port ID. Once the root bridge and port roles are determined, some links remain active and others are blocked to ensure a loop-free Layer 2 topology. HCIA-Datacom emphasizes that the resulting forwarding topology is a tree, not a mesh, even if the physical topology contains redundant links. Understanding the actual forwarding path after STP convergence is important for troubleshooting connectivity, predicting traffic behavior, and verifying whether bridge priority and path-cost settings have produced the intended design outcome in campus switching networks.

RADIUS and HWTACACS are AAA protocols that support accounting functions in addition to authentication and authorization. Accounting records can be used to track login sessions, service usage, command activity, or other information required by the deployment. LDAP and Microsoft Active Directory, by contrast, are directory-based identity technologies. Huawei documentation describes LDAP/AD integration primarily for authentication and authorization by querying directory information and validating user credentials. They are not used as the native AAA accounting protocol between a Huawei AAA client and an AAA server in the same way as RADIUS or HWTACACS. Therefore, when the question asks which listed protocols cannot be used for accounting between the AAA client and AAA server, AD and LDAP are the appropriate selections. RADIUS explicitly carries accounting messages, and HWTACACS also separates and supports authentication, authorization, and accounting functions. The source file leaves the answer blank, but the Datacom AAA model supports a verified answer of B and D.

ACL 2001 is a basic IPv4 ACL because Huawei numbered basic ACLs use the range 2000 to 2999. A basic ACL can match relatively simple conditions such as source IP address and an effective time range, but it does not support matching the IP protocol, destination IP address, or TCP/UDP source and destination port numbers. The attempted rule includes tcp, destination-port eq telnet, and a destination network, all of which require an advanced ACL. Huawei advanced ACLs use the 3000 to 3999 range and can match protocol type, source and destination addresses, and Layer 4 port values. Therefore, even after correcting the obvious command typo from ad 2001 to acl 2001, the rule syntax is still incompatible with a basic ACL 2001 and cannot be successfully configured in that ACL view. To implement the intended policy, the administrator should create an advanced ACL and express the TCP Telnet and destination conditions there. Consequently, the statement that the rule cannot be configured successfully is TRUE, option A.

Both switch ports shown in the exhibit are configured as trunk ports and VLAN 10 is permitted, but the configuration does not change the trunk PVID from its default value of VLAN 1. On Huawei switches, untagged frames received on a trunk interface are associated with the interface PVID. A normal PC sends untagged Ethernet frames, so traffic from both PC1 and PC2 is classified into VLAN 1. VLAN 1 is permitted on a trunk by default unless it is explicitly removed with an undo port trunk allow-pass vlan 1 command. As a result, the two PCs remain in the same Layer 2 broadcast domain through VLAN 1 and can exchange ARP and ICMP traffic. Merely adding VLAN 10 to the allowed VLAN list does not force untagged host traffic into VLAN 10. Therefore, the statement that pinging 192.168.1.2 from PC1 must fail is incorrect. The correct response is FALSE, option B.

The uploaded key includes all four options, but option B is not a valid requirement for normal source NAT and should be removed. Source NAT translates the private source address of outbound traffic into a public address before the packet enters the public network. The public-side router therefore needs reachability to the translated public address for return traffic, not a route to the original private intranet address. By contrast, A can prevent access if NAT is not applied on the proper outbound interface or direction. C can also prevent translation when the configured address pool has no usable address available, depending on the NAT mode and session requirements. D is valid because traffic whose source address does not match the NAT policy or referenced ACL will not be translated; private-source packets then normally cannot traverse the Internet as intended. Routing on the enterprise egress device must of course also be correct, but the specific absence described in B is not inherently a failure when source NAT is working. The verified selections are A, C, and D.

This statement is false . In campus network VLAN planning, VLAN IDs do not have to be allocated strictly consecutively without any gaps. In fact, leaving some reserved VLAN IDs is often a practical and recommended design approach. VLAN planning should focus on clarity, scalability, maintainability, and service separation , rather than on forcing all VLAN IDs to be contiguous.

For example, an administrator may reserve certain VLAN ranges for user access, voice services, management, wireless services, guest access, future expansion, or specific departments. Such structured planning makes later network expansion easier and reduces the risk of service conflicts or disruptive renumbering. HCIA-Datacom emphasizes that good campus network planning should consider current requirements and future growth. Consecutive allocation may look tidy at first, but it can actually reduce flexibility and make later additions more difficult. Therefore, the idea that VLAN IDs must be assigned consecutively without redundancy to avoid omissions is not a correct design principle. Reasonable reservation and categorized allocation are often more beneficial in real enterprise campus networks.

All four configured static routes have the same destination prefix, 20.0.0.0/30, and the question states that every next hop is reachable. Huawei route selection first considers route preference when choosing among routes from the same or different route sources. For static routes, a smaller preference value means a higher priority. The four preferences shown are 60 for next hop 10.1.1.2, 70 for 10.1.2.2, 100 for 10.1.3.2, and 50 for 10.1.4.2. Because 50 is the smallest preference, the route through 10.1.4.2 is selected as the active route in the IP routing table. The other configured static routes can remain as lower-priority alternatives and may become active if the preferred route becomes invalid, depending on reachability and configuration. Equal-cost load balancing would require routes with the same relevant preference and cost after route selection. That is not the case here. Therefore, the next hop of the selected route to 20.0.0.0/30 is 10.1.4.2, making option A correct.

The MAC address table in the exhibit contains learned entries for 0050-5600-0001 on GE1/0/1 and 0050-5600-0002 on GE1/0/2, but there is no entry for destination MAC 0050-5600-0003. A frame arriving from PC1 on GE1/0/1 with an unknown unicast destination is therefore flooded within the VLAN. Huawei Ethernet switching behavior sends the unknown unicast frame through all other eligible Layer 2 interfaces in that VLAN, while never sending it back through the ingress interface. In the shown topology, the remaining interfaces are GE1/0/2, GE1/0/3, and GE1/0/4. Consequently, the frame is sent through options A, D, and B respectively. GE1/0/1, option C, is excluded because it is the ingress interface from which SW1 received the frame. If SW1 later learns 0050-5600-0003 on a specific port, subsequent unicast frames can be forwarded only through that learned port. For the empty destination entry shown, the verified answer is A, B, and D.

Wi-Fi 7 supports operation in the 2.4 GHz , 5 GHz , and 6 GHz frequency bands, so options A , C , and D are correct. These three bands together provide flexible coverage and capacity options. The 2.4 GHz band offers better propagation and wider coverage, while the 5 GHz and 6 GHz bands provide more channels, higher capacity, and better support for high-speed, low-latency services.

Option B , 9.6 GHz , is incorrect because it is not a Wi-Fi 7 operating band. HCIA-Datacom WLAN content highlights Wi-Fi 7 as a major advancement in wireless performance, bringing improvements in throughput, channel usage, spectrum efficiency, and latency characteristics. The addition and use of the 6 GHz band is especially important because it expands available spectrum resources and helps reduce contention in dense wireless environments. In practical enterprise WLAN design, understanding supported frequency bands is essential for channel planning, interference control, device compatibility assessment, and service optimization. This question checks whether the learner can correctly identify the standard operating bands used by modern Wi-Fi 7 networks.

In OSPF, the packet type used to request specific link-state advertisements from a neighbor is the Link State Request (LSR) packet. Therefore, option B is correct. During database synchronization, OSPF neighbors first discover each other with Hello packets, then exchange summaries of their databases using Database Description (DD) packets. If one router finds that it is missing certain LSAs or has older versions, it sends an LSR packet to request the needed LSAs from its neighbor.

The neighbor then responds with a Link State Update (LSU) packet containing the requested LSAs. Finally, the receiving router confirms proper receipt with a Link State Acknowledgment (LSAck) packet. HCIA-Datacom emphasizes understanding the roles of these five OSPF packet types because they are central to neighbor formation, adjacency establishment, and LSDB synchronization. This question specifically tests whether the learner can distinguish between the request packet ( LSR ) and the update packet ( LSU ). The router does not use a DD packet to request detailed LSA content; DD packets provide database summaries, while LSR packets explicitly request the LSAs that are needed.

An Ethernet switch learns MAC address entries dynamically by examining the source MAC address of incoming frames. When SW1 first receives frames from PC1 on GE1/0/1, it creates a MAC address table entry mapping PC1’s MAC address to that port. If PC1 later sends frames that arrive on GE1/0/2, SW1 updates the learned entry to reflect the new incoming interface. Therefore, option B is correct: SW1 saves the mapping between PC1’s MAC address and GE1/0/2 and removes or overwrites the old mapping associated with GE1/0/1.

Option A is incorrect because a single dynamic MAC address is not normally maintained on two different ports within the same VLAN at the same time; that would cause forwarding ambiguity. Option C is incorrect because a normal move of one MAC address does not require clearing the entire MAC table. Option D is also incorrect because switches update MAC learning dynamically upon receiving new source traffic and do not have to wait for the previous entry to age out. HCIA-Datacom uses this principle to explain MAC address learning, migration, and troubleshooting of loops or host movement in switched Ethernet networks.

This statement is true . On a Huawei WAC, the number of APs that can go online is controlled by the available license resources . If a Fit AP fails to come online and the command display ap online-fail-record shows Insufficient license resources , it means the controller does not currently have enough licensed capacity to allow additional APs to register successfully.

In this case, the administrator must expand the license capacity or adjust existing license allocation so that the AP can be admitted. This is a common WLAN deployment issue, especially when new APs are added without first verifying the current AP license limit on the WAC. HCIA-Datacom troubleshooting methodology emphasizes interpreting controller diagnostics and fault records accurately. An AP can fail to go online for many reasons, including CAPWAP reachability problems, version mismatch, authentication issues, or licensing limitations. When the failure reason explicitly indicates insufficient license resources, the troubleshooting direction is clear: the controller’s AP license capacity must be checked and, if necessary, increased. This question tests the ability to map a specific WAC alarm record to the correct operational response.

In an Eth-Trunk working in manual mode , multiple physical member links are bundled into one logical interface to provide higher bandwidth and link redundancy. If one of four 1 Gbit/s member links fails, the Eth-Trunk does not go down as long as at least one valid member link remains active. Therefore, statement A is correct. Since one link has failed and three member links remain available, the total available bandwidth becomes 3 Gbit/s , so statement B is also correct.

Statement C is incorrect because the traffic originally hashed to the failed link is not permanently stopped. Instead, after the link failure is detected, traffic is redistributed across the remaining active member links according to the trunk load-balancing mechanism. Statement D is also incorrect because Eth-Trunk provides link-level redundancy. Existing upper-layer sessions such as TCP are not necessarily interrupted and re-established simply because one member link fails. HCIA-Datacom emphasizes that Eth-Trunk improves reliability and bandwidth utilization by allowing traffic to continue across surviving links when a single member fails. This is one of the main advantages of link aggregation in campus and data center switching networks.

According to the topology and the original question scenario, the correct answer is 10.2.1.1, so option B is selected. In HCIA-Datacom troubleshooting questions of this type, the goal is usually to identify the correct management address, next-hop interface address, or testing destination based on the addressing design shown in the figure.

The answer depends on the role of the device and the direction of the connectivity verification. In such topologies, each interface belongs to a specific network segment, and the selected address must match the intended test target on that segment. If the test is being performed toward the neighboring device or a specific reachable interface, using the correct IP on the proper subnet is essential. An incorrect address may still look familiar from the topology but would not represent the right test endpoint. HCIA-Datacom places strong emphasis on reading topology labels carefully, matching interface addresses to subnet assignments, and choosing the correct destination when using tools such as ping, tracert, or service-specific connectivity tests. This question mainly checks address recognition accuracy in a troubleshooting context.

The root path cost (RPC) of a switch is the total path cost from that switch to the root bridge along the selected spanning-tree path. Since SW1 is given as the root bridge, its RPC is 0. Each link in the topology has a path cost of 20 . To determine SW4’s RPC, you identify the shortest active STP path from SW4 to SW1.

Based on the topology used in the question, SW4 reaches SW1 through a path containing two links . Therefore, the total root path cost is 20 + 20 = 40 , which makes option B correct. This is a standard STP calculation. HCIA-Datacom uses RPC as one of the main comparison parameters in root-port election on non-root switches. A lower RPC means a better path toward the root bridge. If multiple candidate ports have the same RPC, the switch then compares the sender’s bridge ID and port ID. This question checks whether the learner understands that RPC is cumulative across the spanning-tree forwarding path and is not simply the cost of a single directly connected link unless the switch is directly attached to the root bridge.