H12-811_V1.0 HCIA-Datacom V1.0 Exam Questions and Answers

The basic IPv6 header has a fixed length of 40 bytes. Unlike IPv4, the IPv6 header is streamlined, omitting some fields (like header checksum) and standardizing the header size. This simplification reduces processing overhead, enhancing routing efficiency and scalability for modern networks​.

In Huawei's Versatile Routing Platform (VRP), pressing Ctrl+Z is a shortcut that takes the user from any configuration view directly back to the user view. This command is useful for quickly navigating out of multiple levels of configuration back to the main user prompt. This feature is part of the VRP interface management commands for efficient system navigation​.

Private vs Public IPs:

192.168.1.2 belongs to the private IP range (192.168.0.0/16).

Private IP addresses cannot be routed on the Internet and must be translated.

Network Address Translation (NAT):

NAT converts private IP addresses to a public IP so that the device can access the Internet.

Conclusion:

NAT is required to access the Internet from a private IP, making the statement TRUE.

References: HCIA-Datacom V1.0 Certification Guide, Chapter 6: NAT and IP Addressing.

Detailed Explanation:The Priority Code Point (PCP) field in an 802.1Q VLAN tag is 3 bits long, which gives it a value range of 0 to 7. This field is used to indicate the priority of the frame, with higher values indicating higher priority​​.

Detailed Explanation:LSAs (Link-State Advertisements) are the fundamental OSPF messages used to convey network topology information. LSU (Link-State Update), LSR (Link-State Request), and LSACK (Link-State Acknowledgment) are all types of messages related to OSPF's operations, but "LSA" alone is not a valid OSPF message type​.

Detailed Explanation:Static routing does not automatically recover from link failures; manual reconfiguration is required if a static route path becomes invalid. Dynamic routing protocols, on the other hand, adapt automatically to network changes, adjusting routes as needed. (Reference: HCIA-Datacom Training Material, Static vs. Dynamic Routing)

In RSTP (Rapid Spanning Tree Protocol), the Backup port serves as a backup for the Designated port on the same bridge segment, not the root port. If the root port fails, the alternate port, not the backup port, takes over to maintain connectivity to the root bridge. The backup port does not have the capability to replace the root port​.

Comprehensive Explanation: In OSPF, an Area Border Router (ABR) is a router that has interfaces in more than one OSPF area, facilitating communication between different areas. If a router has interfaces in only one OSPF area, it is not an ABR. Based on the network structure, it is incorrect to assume that all routers except RTA are ABRs. A router can only be considered an ABR if it has interfaces connecting to multiple OSPF areas. If a router only connects within one area, it is not an ABR.

Detailed Explanation:SNMPv3 is the version that focuses on security and administration. It offers features such as strong authentication and encryption to secure network management, along with enhancements in administration such as notifications and proxy forwarding​​.

A Layer 2 ACL primarily matches Layer 2 information, such as source and destination MAC addresses. However, it does not match Layer 3 information like IP addresses, as Layer 2 ACLs are designed to control traffic based on MAC addresses rather than IP-based criteria. Layer 3 ACLs would be used to match IP addresses​.

The command defines a static route to the network 10.0.12.0 with a 255.255.255.0 subnet mask, using 192.168.1.1 as the next-hop address. Static routes are manually set routes with fixed paths, and by default, they have higher priority than dynamic routes, but the specific preference value depends on configuration. This setup enables targeted routing for traffic towards the specified destination​.

Detailed Explanation:MAC addresses that start with the first octet having the least significant bit (LSB) of the first byte set to 1 (such as 01-02-03-04-05-06) are multicast MAC addresses, and these cannot be assigned to a host's network interface card (NIC). Only unicast MAC addresses can be assigned to hosts​.

In the IP header at the network layer, the Protocol field specifies the transport layer protocol in use. The protocol number for UDP is 17, not 6. Protocol number 6 is reserved for TCP. This field allows IP packets to be correctly processed by the appropriate transport-layer protocol at the receiving device​.

Detailed Explanation:Access Control Lists (ACLs) are processed in sequential order, meaning that once a packet matches a rule, subsequent rules are ignored. To ensure that more specific (strict) conditions are applied, strict rules should be listed first, followed by loose rules. (Reference: HCIA-Datacom Training Material, ACL Configuration and Rule Order)

Command Output Overview:

The command display startup is used to check the configuration of the startup system software, configuration files, license files, and other related settings on Huawei routers. The output in this case provides details about:

The current system software (ar2220-v200r003c00spc200.cc).

The next startup system software (ar222b-v200r003c00spc200.cc).

Backup and saved configuration files, which are not defined (null).

Analysis of Options:

Option A: "The system file for next startup cannot be modified."This statement is false because the system file for the next startup can be modified using the startup system-software command. The file path for the next startup system software (ar222b-v200r003c00spc200.cc) indicates that it has been configured and can be changed by the administrator. The command syntax is supported as per Huawei's documentation​​.

Option B: "The startup system software <startup-software-name> command can be used to modify the system software for next startup."This is true and matches the functionality provided by Huawei's routers. The command allows administrators to specify the software package to be used at the next system reboot​​.

Option C: "The running configuration file is not saved."This is true as the Startup saved-configuration file is listed as null, meaning that no configuration file has been saved for startup. Saving the running configuration is necessary to ensure settings persist after a reboot​​.

Option D: "The system file used for the current startup is ar2220-v200r003c00spc200.cc."This is true as per the output under Startup system software, which confirms the system file used in the current boot process​​.

Correct Statement Selection:Based on the analysis, the statement "The system file for next startup cannot be modified" is false. This matches the system's behavior, where administrators are allowed to modify the next startup file using relevant commands.

References:

Huawei HCIA-Datacom V1.0 Training Material and Lab Guide​​.

Command-line operations from Huawei routers, as documented in the training materials and lab environments​​.

1. Understanding the ACL Rule

The rule:

rule 5 deny source 100.0.12.0 0.0.0.255

Blocks traffic originating from 100.0.12.0/24 (Host B’s network).

This means any packet sent from Host B to Host A will be blocked.

2. Applying the ACL to the Correct Interfaces

Option A: Applied inbound on GE0/0/1 → Blocks packets from Host B before reaching Host A. ✅

Option B: Applied inbound on GE0/0/2 → Blocks packets from Host A before reaching Host B. ✅

3. Why Other Options Are Incorrect

Option C (GigabitEthernet0/0/3):

Interface GE0/0/3 is not connected to Host A or Host B, so applying ACL here is meaningless.

Option D (Outbound on GE0/0/1):

Outbound filtering is less efficient than inbound filtering because it blocks traffic after routing.

4. Correct Approach to Prevent Communication

To completely block communication between Host A and Host B, we must:✅ Block inbound traffic on GE0/0/1 (Host A’s interface)✅ Block inbound traffic on GE0/0/2 (Host B’s interface)

Conclusion:

The correct choices are A and B because they block inbound traffic at the correct interfaces.

Options C and D are incorrect because they apply ACL rules to the wrong interfaces or use inefficient filtering.

References:✅ HCIA-Datacom V1.0 Certification Guide, Chapter 5: ACL Configuration

Eth-Trunk Functionality:An Eth-Trunk interface can operate as both a Layer 2 and Layer 3 interface depending on the configuration. For example:

As a Layer 2 interface, it can aggregate Ethernet links for switching.

As a Layer 3 interface, it can aggregate links for routing​.

Correct Answer:FALSE. Eth-Trunk interfaces can function as both Layer 2 and Layer 3 interfaces.

Detailed Explanation:Each Virtual Access Point (VAP) on an AP is identified by a unique Basic Service Set Identifier (BSSID), which is the MAC address used at the data link layer. The SSID is a human-readable network name, while the BSSID is the technical identifier​.

Comprehensive Explanation: OSPF (Open Shortest Path First) is a link-state routing protocol. It builds a complete map of the network's topology using Link-State Advertisements (LSAs) and makes routing decisions based on this map. Protocols like Static and Direct are not dynamic routing protocols, while FTP is a file transfer protocol

PPP (Point-to-Point Protocol) is versatile and allows IP addresses on each end of a link to belong to different subnets. This capability supports flexible WAN (Wide Area Network) connections where different subnet addressing schemes may be required. This flexibility is part of PPP's design, allowing it to function effectively over varied network architectures​.

Comprehensive Explanation: In Spanning Tree Protocol (STP), the Message Age in the BPDU (Bridge Protocol Data Unit) sent by the root bridge is set to 0. As BPDUs are forwarded by non-root switches, the Message Age is incremented. This timer is used to ensure that outdated information is not propagated indefinitely through the network. If the Message Age reaches a configured maximum value, the BPDU is discarded, and the network topology is recalculated.

Device Interconnection Requirements:

Device interconnection (such as point-to-point links) requires only two IP addresses: one for each device.

A subnet mask of /30 (255.255.255.252) provides four total addresses (2 usable, 1 network, 1 broadcast).

Efficiency:

Using a /30 subnet avoids wasting IP addresses, making it ideal for point-to-point links.

Why Other Options Are Incorrect:

B (32): /32 is used for single-host IP addresses, not links.

C (24): /24 is excessive for point-to-point links, providing 254 usable addresses.

D (16): /16 provides 65,534 addresses, which is highly inefficient.

References: HCIA-Datacom V1.0 Certification Guide, Chapter 3: IP Addressing.

Understanding Loops in Layer 2 Networks:

Layer 2 switches flood broadcast and unknown unicast packets.

If there is a loop, these packets can circulate indefinitely, leading to a broadcast storm.

Consequences of Broadcast Storms:

High CPU usage on network devices.

Degraded network performance or complete failure.

Solution:

Spanning Tree Protocol (STP) is implemented to prevent loops by selectively blocking redundant links.

Conclusion:

Since loops lead to broadcast storms, the statement is TRUE.

References: HCIA-Datacom V1.0 Certification Guide, Chapter 8: Spanning Tree Protocol.

Detailed Explanation:

Dynamic routing protocols, such as OSPF and RIP, automatically discover and generate routes, adjusting when network topology changes occur. This helps in reducing the manual configuration required by static routes and ensures that the network adapts efficiently to changes such as link failures or the addition of new routes.

Comprehensive Explanation: To prevent unauthorized changes to the router's configuration, the administrator can take several steps. Configuring an ACL to restrict management access ensures that only authorized users, such as the administrator, can log in to the router. Additionally, using AAA (Authentication, Authorization, and Accounting) allows the administrator to manage user permissions and control access to the router's functions based on user roles. Port-security is used for limiting MAC addresses on switch ports, and login privilege levels should be set appropriately but not limited to level 0, which restricts almost all actions.

Network Layers in Campus Design:

The three common layers in a campus network are:

Core Layer: Provides high-speed backbone connectivity.

Aggregation Layer: Consolidates traffic and applies policies.

Access Layer: Connects end devices like PCs and phones.

Why "Network Layer" Is Incorrect:

"Network layer" is not a term used to describe physical or logical architecture in campus networks. It refers to Layer 3 in the OSI model, which is about IP routing.

Why Other Options Are Correct:

Core, access, and aggregation layers are widely used in hierarchical network design.

References: HCIA-Datacom V1.0 Certification Guide, Chapter 4: Campus Network Design.

Dynamic IGP Routing Protocols:

OSPF (Open Shortest Path First): A dynamic IGP that uses link-state information for routing within an autonomous system​​.

Analysis of Options:

Option A: "Static" refers to manually configured routes, not dynamic.

Option B: "BGP" is a dynamic routing protocol but an EGP, not an IGP.

Option C: "Direct" refers to routes learned from directly connected networks and is not dynamic.

Option D: "OSPF" is a dynamic IGP, making it the correct choice.

Correct Answer:The dynamic IGP routing protocol is D (OSPF).

In trunk mode, the interface can forward frames tagged with VLANs specified in the allow-pass list (here, VLAN 100) without removing tags. However, if an untagged frame is received, it is assigned to the PVID (here, VLAN 200). This configuration allows both tagged and untagged traffic, with the PVID determining the VLAN for untagged frames​.

In OSPF, routers first synchronize their LSDBs (Link-State Databases) through an exchange of LSAs (Link State Advertisements) before reaching the Full state. Only after full synchronization of the LSDB does the OSPF neighbor state move to Full. This ensures both routers have consistent routing information before establishing full adjacency​.

Main Functions of Routers:Routers primarily operate at the Network Layer (Layer 3) of the OSI model, forwarding data packets based on destination IP addresses and maintaining routing tables for decision-making.

Analysis of Options:

Option A: "Routers forward data packets based on source IP addresses" is incorrect, as routers use the destination IP address in a packet to determine its forwarding path, not the source IP address​​.

Option B: "Routers enable devices on the same network segment to communicate with each other" is not a function of routers. Devices on the same segment communicate using switches or hubs, which operate at the Data Link Layer (Layer 2)​​.

Option C: "Routers forward data packets according to routing tables" is a correct function, as routers rely on routing tables to determine the best path for forwarding packets.

Option D: "Routers learn routes through multiple routing protocols and add them to the routing table" is a correct function of routers in dynamic routing scenarios​.

Correct Answer:The functions A and B are not main functions of routers.

Error Analysis:The error message indicates that the command entered is not recognized by the device. This typically occurs when the syntax is incorrect or the first keyword of the command is unrecognized. The system identifies the problem location ('A' position), which points to the initial part of the command.

Analysis of Options:

Option A: "The entered parameter is not specified" refers to cases where a valid command is incomplete due to missing parameters, not an unrecognized command. This is unrelated to the error displayed.

Option B: "The entered command is incomplete" applies when additional parameters are needed to complete the command. However, the system explicitly states "unrecognized command," ruling this out.

Option C: "The parameter type is incorrect" refers to an error where a parameter is of the wrong type (e.g., string instead of integer). This is not related to keyword recognition.

Option D: "No keyword is found" directly aligns with the error message, as the system cannot recognize the first keyword of the command, making it the correct answer​​.

IPv6 Address Types:

Unicast: Identifies a single interface.

Anycast: Identifies a set of interfaces, delivering to the nearest one.

Multicast: Delivers to multiple interfaces.

Broadcast: Does not exist in IPv6; replaced by multicast addressing​​.

VLAN Assignment Overview:VLAN (Virtual Local Area Network) assignment is a critical step in campus network planning. It involves logically segmenting a network to improve manageability, security, and performance. Huawei recommends various approaches based on specific needs.

Analysis of Options:

Option A: "VLAN assignment by service type"This method groups devices based on the type of service they require (e.g., voice, video, data). It helps in isolating traffic for different service types, improving QoS and security. This is a common practice in network planning​​.

Option B: "VLAN assignment by logical area"Logical area-based assignment groups devices based on their logical function in the network (e.g., core, access, distribution). It ensures proper segmentation and alignment with network topology​.

Option C: "VLAN assignment by geographic area"Assigning VLANs based on geographic areas (e.g., floors in a building, departments) helps localize traffic within a region, reducing unnecessary cross-network traffic​​.

Option D: "VLAN assignment by personnel structure"While this option suggests assigning VLANs based on organizational structure (e.g., employees, managers), it is not a typical practice in VLAN assignment. It lacks scalability and alignment with network topology, making it an inefficient approach​.

Correct Answers:The valid VLAN assignment methods in campus network planning are:

A. By service type

B. By logical area

C. By geographic area

Detailed Explanation:All listed options are valid OSPF (Open Shortest Path First) packet types:

HELLO packets establish and maintain neighbor relationships.

LSR (Link State Request) packets are used to request missing link-state information.

LSU (Link State Update) packets contain link-state advertisements for OSPF routers.

LSA (Link State Advertisement) packets carry route information.(Reference: HCIA-Datacom Training Material, OSPF Packet Types)

Static IP addressing for servers in campus network planning is crucial for maintaining stable network access to server resources. Static IPs ensure that critical devices like servers have fixed addresses, allowing for predictable network access and reducing potential IP conflicts, which enhances network reliability. This practice is endorsed in Huawei's guidelines for effective campus network design and is considered a best practice for managing servers on a network​.

Comprehensive Explanation: In Telnet sessions, different privilege levels determine what actions a user is allowed to perform. If users are not able to configure the IP address, it is likely that their privilege level is set incorrectly. The administrator must ensure that the Telnet users are assigned the correct privilege level (typically level 15 for full administrative rights) to allow configuration changes, including IP address modifications.

Comprehensive Explanation: On a network consisting of multiple broadcast domains (like Ethernet links), OSPF will elect one DR (Designated Router) and one BDR (Backup Designated Router) per broadcast segment. In this topology, two Ethernet segments are formed, so two DRs will be elected​

Comprehensive Explanation: A routing table contains several key elements:

Cost: Also known as metric, this indicates the cost associated with reaching a specific destination, such as the number of hops or link speed.

Next-hop address: This is the IP address of the next device along the route that packets should be forwarded to.

Protocol: The routing protocol (e.g., OSPF, RIP) that determined the route.

Interface: The physical or logical interface through which the router sends packets to reach the destination.

Destination/Mask: The destination network or subnet and the associated subnet mask define the range of IP addresses for which this route is valid. These elements together allow routers to efficiently forward traffic to the correct destinations.

Comprehensive Explanation: In RSTP (Rapid Spanning Tree Protocol), G0/0/3 of SWB is an Alternate Port because it provides a redundant path to the root bridge, while G0/0/3 of SWA is a Designated Port, forwarding traffic away from the root bridge. Similarly, G0/0/2 of SWA is also a Designated Port because it forwards traffic to other segments of the network. Alternate Ports are used to provide backup paths, while Designated Ports are the forwarding ports on a given segment.

Comprehensive Explanation: The command dot1q termination vid 100 in the configuration specifies that the sub-interface is configured to receive tagged data frames for VLAN 100. VLAN tagging ensures that frames are properly identified and routed through the correct VLAN, and the sub-interface is associated with a specific VLAN ID to handle the tagged traffic.

In Huawei’s VRP system, the login timeout setting is applied specifically to Virtual Terminal (VTY) interfaces, which manage remote access connections such as Telnet or SSH. Configuring a login timeout on a VTY interface helps secure remote sessions by automatically disconnecting inactive users after a specified period​.

Detailed Explanation:The default Router Dead Interval in OSPF is 40 seconds for broadcast and point-to-point networks. This interval defines the time period a router waits to receive hello packets before declaring a neighbor as down. (Reference: HCIA-Datacom Training Material, OSPF Hello and Dead Intervals)

Detailed Explanation:The command forward-mode direct-forward is used to configure the AC to enable direct forwarding, meaning that the AP will forward user data packets directly to the network without tunneling them through the AC, improving efficiency by reducing the load on the AC​.

Detailed Explanation:To manage a router in a remote branch office, Telnet is a suitable option as it allows remote access over a network. Unlike a console connection, which requires physical access, Telnet enables remote management as long as the administrator has network connectivity to the router. FTP is used for file transfer, and DHCP is used for dynamic IP address allocation, not for management​​.

Comprehensive Explanation: The user-interface maximum-vty command is used on Huawei devices to configure the maximum number of simultaneous VTY (Virtual Terminal Line) users who can log in via Telnet. By limiting the number of VTY sessions, the administrator can control how many users are able to access the device at the same time, preventing excessive connections that may overwhelm the device or reduce security.

Configuration Analysis:

The router has two DHCP pools (pool1 and pool2).

Interface Gi/0/0 is assigned the IP address 10.10.10.1/24 and is configured to use global DHCP.

Reasoning:

The IP address 10.10.10.1 indicates that the interface belongs to the 10.10.10.0/24 network segment.

DHCP assigns IP addresses based on the network of the interface. Therefore, the host will receive an IP address from pool1 (10.10.10.0/24).

The VRP platform does not support configuration through FTP. Configuration methods typically include using a console port, Telnet, or SSH, allowing for direct access to the device configuration. FTP is generally used for file transfer, not direct configuration, and therefore is not a supported method for configuring a router​.

Comprehensive Explanation: The wildcard mask 0.0.254.255 corresponds to a range of IP addresses where the second octet can vary between 2 and 4, and the third octet can vary between 0 and 255. This means the ACL rule matches IP addresses in the range 10.0.2.0 to 10.0.4.255. The only option that falls within this range is 10.0.4.5, making it the correct answer.

Comprehensive Explanation: The output shows that the current and next startup configurations are different. Specifically, the startup saved-configuration file is flash:/vrpcfg.zip, and the next startup saved-configuration file is flash:/backup.zip, indicating that changes have been made and the system will use a different configuration file at the next reboot​

Detailed Explanation:Local Area Networks (LANs) cover a small geographic area, such as a home or office. They typically connect computers and devices within a limited area, such as a single building. In this case, both a home network and an office network of a company qualify as LANs. On the other hand, a Metropolitan Area Network (MAN) covers a city-wide area, and the Internet is a global network, so these are not LANs .

Detailed Explanation:In Python, the telnetlib module is indeed used to implement the Telnet protocol, providing functionality for interacting with remote devices over Telnet​.

Comprehensive Explanation: On Huawei VRP, the default route preference is as follows: Direct routes have the highest preference, followed by OSPF, Static, and then RIP. Direct routes are preferred because they represent directly connected networks​

In Huawei’s VRP, the default preference value for OSPF routes is generally 10, but this value can be adjusted based on configuration requirements. Therefore, it is not necessarily always set to 10, as network administrators may alter the preference to prioritize different routes. This flexibility allows customization based on the network's specific routing needs​.

Detailed Explanation:The address 145.4.2.55/26 is a valid unicast address and falls within the range of usable IP addresses for a /26 subnet. The address 237.6.1.2/24 is from a reserved range, 127.3.1.4/28 is part of the loopback range (127.0.0.0/8), and 192.168.10.112/30 only provides two usable addresses, which would not allow the router to be properly configured .

Detailed Explanation:APs can be added to an AC using multiple methods. You can add them when they are online, offline, or allow the AC to automatically discover them. Additionally, unauthorized APs can be manually confirmed for security​.

Understanding Trunk Ports:

Trunk ports carry traffic from multiple VLANs.

Native VLAN (PVID) frames are sent untagged on the trunk.

Breakdown of Configuration:

port link-type trunk → Interface operates as a trunk.

port trunk pvid vlan 10 → Sets VLAN 10 as the native VLAN.

port trunk allow-pass vlan 10 20 30 40 → Allows traffic from VLANs 10, 20, 30, and 40.

Conclusion:

Since VLAN 10 is the PVID (native VLAN), frames from this VLAN are sent untagged.

Correct answer is A (VLAN 10).

References: HCIA-Datacom V1.0 Certification Guide, Chapter 4: VLANs and Trunking.

Comprehensive Explanation: Host A and Host B cannot communicate because they are in different subnets. Host A's IP address is 10.0.12.1/30, while Host B's IP address is 10.0.12.5/24. Since they are in different subnet ranges and there is no router in the diagram to perform inter-subnet routing, direct communication between them is not possible without a router to route traffic between the different subnets.

In OSPF networks, a DR (Designated Router) is elected for each broadcast domain, such as each Ethernet segment. Given the topology where there are multiple Ethernet segments, a DR will be elected in each segment, resulting in three DRs based on the configuration and network design​.

Comprehensive Explanation: An ACL (Access Control List) is used to define rules for permitting or denying packets based on criteria such as IP addresses, protocols, or ports. However, the ACL only takes effect when it is applied to a service module, such as an interface or a firewall rule. This ensures that traffic is filtered according to the ACL rules as it passes through the device. Without being applied, the ACL rules are inactive and do not influence traffic.

Detailed Explanation:Layer 2 switches operate at the data link layer, handling frames based on MAC addresses. They maintain a MAC address table to record mappings between MAC addresses and interfaces, allowing efficient frame forwarding within the local network. (Reference: HCIA-Datacom Training Material, Layer 2 Switching and MAC Address Learning)

In OSPF, the "Full" state signifies that the neighbor relationship has been fully established, with both routers synchronized and their LSDBs updated. This state is achieved after exchanging and acknowledging Link State Advertisements (LSAs) between the neighbors, marking the completion of OSPF adjacency​.

With a subnet mask of /25, the IP range for this subnet would be 192.168.1.0 to 192.168.1.127. Here, 192.168.1.127 is the last usable address in the subnet, making it a valid host address rather than a network or broadcast address. This address falls within the range of available host addresses for that subnet​.

Detailed Explanation:The EUI-64 format splits a MAC address into two parts and inserts "FFFE" in the middle. The Universal/Local (U/L) bit is flipped, so a valid EUI-64 address would be 02E0-FCEF-FFFE-0FEC​.

Detailed Explanation:Small campus networks are characterized by simple architecture, limited user counts, and straightforward network requirements. Wide coverage is typically associated with larger campus or enterprise networks. (Reference: HCIA-Datacom Training Material, Campus Network Characteristics)

Detailed Explanation:Static MAC address entries are manually configured and stored in the switch's configuration file, making them persistent across reboots. These entries remain in the MAC address table after a restart, unlike dynamic entries, which are lost. (Reference: HCIA-Datacom Training Material, MAC Address Table Types)

Detailed Explanation:The Type/Length field value of 0x0800 indicates that the upper-layer protocol is IPv4. However, the length of the IPv4 header can range from 20 to 60 bytes, not the length of the entire upper-layer packet. The field refers to the type of the encapsulated protocol, and the length is not constrained to the header alone​​.

Detailed Explanation:In a "one-armed routing" setup, a router with sub-interfaces can handle inter-VLAN routing by logically segmenting traffic within a single physical interface. In this configuration, each department (Administration and Finance) is assigned a different VLAN with separate sub-interfaces on Router R1.

In such a setup, communication between different VLANs (i.e., inter-VLAN routing) is handled by the router, even without Proxy ARP enabled. The router can directly route packets between the VLANs as it is aware of the different networks and performs Layer 3 forwarding based on the IP address of each VLAN's sub-interface.

Thus, even if ARP Proxy is disabled, devices in the Administration and Finance departments can communicate through the router because inter-VLAN routing takes place at Layer 3 without relying on ARP proxy functionality​​​.