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

Detailed Explanation:While a switch will typically forward a unicast frame based on its MAC address table, certain scenarios like port security or VLAN restrictions may prevent the frame from being forwarded even if a MAC entry exists. (Reference: HCIA-Datacom Training Material, MAC Address Table and Frame Forwarding)

Comprehensive Explanation: The PVID (Port VLAN ID) is the VLAN to which untagged data frames are assigned on a hybrid port. In this configuration, the port hybrid untagged vlan 4 6 command indicates that VLANs 4 and 6 are untagged, and the PVID will be the lowest untagged VLAN, which is VLAN 4. Tagged frames for VLANs 2, 3, and 100 will be forwarded as tagged, but untagged traffic will belong to VLAN 4 by default.

Comprehensive Explanation: To remove the Eth-Trunk interface, you can simply use the undo interface Eth-Trunk 1 command. This command deletes the entire Eth-Trunk interface from the switch configuration. The other commands involve additional steps to unbind physical interfaces from the Eth-Trunk, but these steps are unnecessary if you are deleting the Eth-Trunk interface entirely.

This explanation was already provided earlier. Please refer to QUESTION NO: 13 at the start.

Detailed Explanation:In this scenario, the MAC address 00e0-fc99-9999 is associated with multiple IP addresses through dynamic ARP learning, indicating that the host’s IP has changed several times. The ARP table on the switch shows multiple entries with different IPs mapped to the same MAC address, which is common when a device frequently updates its IP. As ARP is a dynamic protocol, these entries reflect the device's current and past IP associations. (Reference: HCIA-Datacom Training Material, ARP Operation and IP-MAC Mapping)

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​​​.

Detailed Explanation:

Option B: OSPF supports triggered updates, allowing routing tables to be updated only when changes occur, conserving bandwidth.

Option D: OSPF supports area division, which is essential for optimizing large networks and limiting the scope of link-state advertisements.

Option A is incorrect because OSPF calculates the shortest path based on cost, not hop count.

Option C is incorrect; OSPF prevents routing loops by maintaining a loop-free topology through its link-state database.

(Reference: HCIA-Datacom Training Material, OSPF Features)

Detailed Explanation:In a Layer 2 WLAN, an Access Controller (AC) typically handles authentication and management but does not act as a gateway. Instead, a Layer 3 device, such as a router, serves as the gateway. (Reference: HCIA-WLAN Training Material, WLAN Layer 2 and Layer 3 Concepts)

To form an EUI-64 address, the MAC address is split and FFFE is inserted in the middle, making the EUI-64 format 00E0-FCEF-FFFE-0FEC. Additionally, the 7th bit of the first byte is flipped to form the Modified EUI-64 address used in IPv6 for Stateless Address Autoconfiguration (SLAAC)​.

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​.

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​.

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​.

Detailed Explanation:

The subnet 200.200.200.200/30 allows two usable IP addresses, 200.200.200.201 and 200.200.200.202. These two addresses can communicate with each other directly, without the need for routing .

An Ethernet II frame has a standard length range of 64 to 1518 bytes, including the Ethernet header. This range accounts for both the minimum frame size (to prevent collisions) and the maximum frame size (to avoid excessive delay). This specification is in line with IEEE 802.3 standards for Ethernet frames​.

Detailed Explanation:The protocol number for TCP in the IPv4 header is 6. Since Telnet uses TCP as its transport layer protocol, the protocol field in the IPv4 header will contain the value 6​​.

Comprehensive Explanation: In STP (Spanning Tree Protocol), ports can be in several states, including:

Discarding: The port is not forwarding traffic, either because it is in a blocking state or not participating in active forwarding.

Listening: The port is processing BPDUs and is preparing to transition to either the learning or forwarding state. No data frames are forwarded during this state.

Forwarding: The port is actively forwarding traffic as part of the active network topology.

The "Disabled" state is not part of the STP protocol but rather represents a port that is administratively shut down or not participating in the STP process.

Understanding Timers:

Forward Delay Timer: Default value is 15 seconds, not 20 seconds.

Max Age Timer: Default value is 20 seconds.

Hello Timer: The default interval is 2 seconds for BPDU transmission.

Switch Role:

The output indicates that the switch is not the root bridge, confirming option D is correct.

Conclusion:

Statement A is incorrect as the Forward Delay timer is not 20 seconds.

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

Trunk Interface Basics:

Trunk interfaces are used to carry traffic for multiple VLANs between switches.

Tagged frames include VLAN identifiers, while untagged frames belong to the native VLAN.

Untagged Frames:

Frames from the native VLAN are sent untagged on the trunk interface.

Conclusion:

Trunk interfaces support both tagged and untagged frames, so the statement is TRUE.

References: HCIA-Datacom V1.0 Certification Guide, Chapter 4: VLAN Basics.

DHCP (Dynamic Host Configuration Protocol) can allocate various network parameters, including:

IP address: Assigns a unique IP to each client.

Gateway address: Provides the default gateway for routing traffic.

DNS server address: Allows domain name resolution. The DHCP server does not assign an operating system, as this is outside its scope​.

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)

Comprehensive Explanation: Static NAT (Network Address Translation) can implement both one-to-one and many-to-one mappings. In a one-to-one mapping, each private IP address is mapped to a unique public IP address. However, in some cases, static NAT can be configured to map multiple private addresses to a single public address, particularly for services that do not require incoming connections. This flexibility allows for more efficient use of limited public IP address space.

The Bridge ID, a combination of bridge priority and MAC address, is used to determine the root bridge in STP. The switch with the lowest Bridge ID becomes the root bridge. If bridge priorities are identical, the switch with the lowest MAC address is selected as the root bridge​.

The default port number for Telnet is 23. This standard port assignment allows Telnet clients to connect to Telnet servers, facilitating remote management and troubleshooting tasks on network devices. Ports are preassigned to services to streamline network communication and reduce conflicts​.

MAC Address Analysis:

MAC addresses starting with 01-00-5E are reserved for IPv4 multicast by the IANA.

Why Other Options Are Incorrect:

A: The address is valid and reserved for multicast.

C: Broadcast addresses use FF-FF-FF-FF-FF-FF.

D: Unicast addresses are typically hardware-assigned and do not use this prefix.

References: HCIA-Datacom V1.0 Certification Guide, Chapter 7: Ethernet Basics.

Comprehensive Explanation: Hybrid interfaces are capable of carrying both tagged and untagged VLAN frames. They can remove VLAN tags from certain VLANs when sending data frames, depending on the configuration. The command port hybrid untagged vlan x allows a hybrid interface to transmit data frames for VLAN x without a tag, while still tagging other VLANs as required. Hybrid interfaces are flexible and can be used for trunking, but unlike pure trunk ports, they do not always require VLAN tags.

In VRP, the "-a" parameter in the ping command allows specifying a source IP address for the echo request. This can be helpful in testing connectivity from a specific interface on the device, which is useful in verifying path accessibility or troubleshooting issues with certain network segments​.

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.

Comprehensive Explanation: Fit APs (Access Points) are designed to work in conjunction with an Access Controller (AC). They rely on the AC for configuration, management, and control of their wireless services. Without an AC, a Fit AP cannot function independently or provide wireless services. This is in contrast to Fat APs, which have their own management capabilities and can operate independently.

Detailed Explanation:When bridge priorities are identical, STP elects the switch with the lowest MAC address as the root. Here, Switch B has the lowest MAC address (00-e0-fc-00-00-10), making it the root switch. (Reference: HCIA-Datacom Training Material, STP Root Bridge Election)

Routing Table and Equal-Cost Routes:When multiple routes to the same destination network have the same cost (e.g., metric or administrative distance), they are referred to as "equal-cost routes." Routers use load balancing to distribute traffic across these routes​​.

Analysis of Options:

Option A: "Sub-optimal routes" are routes that are not preferred due to higher cost or less desirable metrics.

Option B: "Multipath routes" is a general term but does not specify equal cost, making it less precise.

Option C: "Equal-cost routes" is correct as the scenario specifies the same destination network with the same cost.

Option D: "Default routes" are used when no specific route matches the destination, which is unrelated to the given scenario​.

Correct Answer:The routes are C (Equal-cost routes).

Detailed Explanation:The priority (preference) of static routes can indeed be manually specified in Huawei devices. By default, static routes have a preference of 60, but this can be changed to create backup routes or prioritize certain routes over others.

ICMP and NAPT:ICMP packets do not have port numbers, but NAPT (Network Address and Port Translation) can still manage ICMP traffic by matching identifiers in the ICMP header. This allows NAPT to handle ICMP messages properly​​.

Correct Answer:FALSE. ICMP packets can be handled by NAPT.

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​.

Routers can learn routes from various sources:

Static routes: Manually configured routes.

Direct routes: Routes to networks directly connected to the router.

Summary routes: Aggregated routes summarizing multiple networks, often used in routing protocols.

Dynamic routes: Routes learned via routing protocols like OSPF, RIP, or BGP. These sources contribute to the router's routing table, enabling it to forward packets to known destinations​.

Detailed Explanation:To accommodate 26 hosts, the subnet needs at least 30 addresses (including network and broadcast addresses). A subnet mask of 255.255.255.192 provides 64 addresses (2^6 - 2 = 62 usable addresses), which is more than enough to support 26 hosts while also leaving space for additional hosts if needed.

Detailed Explanation:UDP (User Datagram Protocol) is a connectionless protocol that does not provide reliability, packet sequencing, or traffic control. These features are usually managed by TCP, which is used for applications requiring reliable data transmission. UDP’s design makes it suitable for real-time applications, such as video streaming or VoIP, where speed and low latency are prioritized over reliability. (Reference: HCIA-Datacom Training Material, UDP Characteristics)

SNMPv3 was designed with enhanced security and administration features compared to previous versions. It offers robust authentication and encryption to protect against unauthorized access and eavesdropping, as well as improvements in administration with support for notification originators and proxy forwarders. These advancements make SNMPv3 the preferred version for secure network management​.

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.

Detailed Explanation:DNS (Domain Name System) is responsible for translating human-readable domain names (like www.example.com ) into IP addresses, enabling devices to locate services on a network. (Reference: HCIA-Datacom Training Material, DNS Function and Protocol Overview)

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.

The PVID (Port VLAN ID) for a hybrid port refers to the VLAN that is assigned to untagged traffic. In this case, VLAN 4 is specified as untagged, making it the PVID for this interface. Traffic received without a VLAN tag is associated with VLAN 4 upon entering the switch​.

Detailed Explanation:Stateless Address Autoconfiguration (SLAAC) allows IPv6 hosts to generate their own IP addresses but does not include DNS server information. DHCPv6 is typically required for DNS configuration. (Reference: HCIA-Datacom Training Material, IPv6 SLAAC and DNS)

Comprehensive Explanation: In STP (Spanning Tree Protocol), the root bridge is elected based on the lowest Bridge ID. The Bridge ID consists of two parts: the bridge priority and the MAC address of the switch. The switch with the lowest Bridge ID is elected as the root bridge. If two switches have the same priority, the switch with the lowest MAC address becomes the root. Other parameters such as Port ID and Root path cost are used in subsequent decisions to determine the best paths to the root bridge, but they are not used in the root bridge election itself.

Router Functionality:Routers operate at the Network Layer (Layer 3) of the OSI model. They use IP addresses to forward packets between different networks and determine the best path for data transmission based on routing tables​​.

Analysis of Options:

Option A: "Network layer" is correct, as routers are Layer 3 devices.

Option B: "Transport layer" handles end-to-end communication and reliability (e.g., TCP/UDP), not routing.

Option C: "Data link layer" is for local node-to-node data transfer (e.g., MAC addresses), handled by switches.

Option D: "Application layer" is for user-facing software interactions (e.g., HTTP, FTP).

Correct Answer:Routers work at the A (Network layer).

Comprehensive Explanation: A routing table contains information necessary for the router to determine the best path to forward packets. This includes the destination network or subnet (Destination/Mask), the next-hop address (the IP address of the next device in the path), and the cost (metric) associated with the route. MAC addresses are used at the Data Link layer (Layer 2) for local network communication and are not part of the routing table, which operates at the Network layer (Layer 3).

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​

Comprehensive Explanation: The Transport layer (Layer 4) in the OSI model is responsible for end-to-end error checking, flow control, and reliable data transmission. It ensures that data is properly sequenced, without errors, and flow-controlled between the sender and receiver. Protocols such as TCP (Transmission Control Protocol) operate at this layer, providing mechanisms for retransmitting lost packets and maintaining the reliability of a session​​​

Comprehensive Explanation: SWA has the lowest Bridge ID and is the root bridge. In this topology, G0/0/2 of SWA and G0/0/1 of SWC are forwarding ports. Since G0/0/3 of SWB provides an alternate path to the root bridge, it will be placed in a blocking state to prevent network loops. The Spanning Tree Protocol ensures that only the most efficient path to the root bridge is active, and alternate paths are blocked until needed.

If host A already has host B’s MAC address in its ARP cache, it can send packets directly to host B without needing to perform an ARP request. This cached information allows immediate packet delivery, assuming no network changes have occurred that would invalidate the ARP entry​.

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​.

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​​.

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)

WEP (Wired Equivalent Privacy) supports open authentication, which allows any client to associate with the network without verifying credentials. This form of authentication is considered insecure by modern standards, as it provides minimal protection for network access. WPA and WPA2 rely on pre-shared keys or 802.1X authentication, which are more secure and do not use open authentication​.

Detailed Explanation:When a command entered on Huawei’s Versatile Routing Platform (VRP) is incomplete, VRP generates an error message indicating that the command is incomplete at a specific position (designated by 'A'). This message helps administrators identify where additional parameters are needed to complete the command syntax. Other error messages indicate issues such as excess parameters or ambiguous commands. (Reference: HCIA-Datacom Lab Guide, VRP Command Syntax)

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

Command Overview:The Huawei Versatile Routing Platform (VRP) uses specific commands to manage file systems and view directory contents. While the dir command is used to list files in the current directory, the pwd command is not supported in VRP environments. Instead, the current working directory is displayed as part of the command prompt in VRP​​​.

Command Analysis:

dir Command:This command is supported and displays the list of files and subdirectories in the current directory. Example:

dir

Output includes filenames, sizes, and other metadata.

pwd Command:The pwd command is commonly used in UNIX/Linux systems to print the current working directory. However, this command is not available on VRP. VRP automatically shows the current directory in its prompt, making pwd unnecessary.

Correct Answer:Since only dir is valid, the statement is false. The correct answer is B (FALSE).

Detailed Explanation:

In RSTP (Rapid Spanning Tree Protocol), if an edge port receives a BPDU (Bridge Protocol Data Unit), it loses its edge status and becomes a regular STP port. This ensures that the edge port behaves as expected when connecting to another switch.

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​.

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​​.

Comprehensive Explanation: The country code setting on wireless devices like access points determines the allowable transmission frequencies and maximum transmission power based on the regulatory requirements of the specific region. For example, certain frequency channels or power levels may be restricted in different countries to avoid interference with other services, and the country code configuration ensures that the device operates within those legal limits.

Comprehensive Explanation: The "-i" parameter in the Ping command on Huawei VRP (Versatile Routing Platform) is used to specify the source IP address for sending an Echo Request (ping) packet. This is useful in cases where the router has multiple interfaces and you want to control which interface is used to initiate the ping. By defining the source IP address, the ping request can be sent from a specific interface on the router, enabling network administrators to test connectivity from that interface.

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​.

Understanding ARP Entries:

Each ARP entry associates a MAC address with an IP address dynamically or statically.

In the table, the MAC address 00e0-fc99-9999 is linked to multiple IP addresses across different interfaces.

Dynamic MAC Address Assignment:

As the host changes its IP address, the MAC address remains consistent.

Conclusion:

The statement is TRUE because the MAC address 00e0-fc99-9999 appears with three different IP addresses dynamically.

References: HCIA-Datacom V1.0 Certification Guide, Chapter 5: ARP Protocol.