A large shopping mall configures a VLAN pool to prevent network performance deterioration caused by potentially large broadcast domains. A network engineer runs the display vlan pool name STA command to check information about the VLAN pool. The following command output is displayed: <AC> display vlan pool name STA Name : STA Total : 2 Assignment: hash Threshold Notify Count: 3 Threshold Notify time(min): 3 VLAN ID : 2 4 Which of the following statements are true?
Correct Answer: A,C
The command output confirms that the VLANs with IDs 2 and 4 are part of the VLAN pool named "STA." The VLAN pool concept is used to allocate VLANs dynamically to devices or subnets, which reduces broadcast domain size and improves network efficiency. The total number of VLAN pools is unrelated to this output, and the assignment algorithm (hash or even) is not explicitly mentioned in the output. Huawei VLAN pool management references align with this analysis .
H12-821_V1.0 Exam Question 117
In BGP, the origin attribute of the routes imported using the import-route command is incomplete.
Correct Answer: A
When routes are imported into BGP using the import-route command, the origin attribute is set to incomplete by default. This indicates that the route's origin is not known or is from an external source, as opposed to being explicitly learned through an IGP (IGP) or EGP (EGP) protocol .
H12-821_V1.0 Exam Question 118
OSPF routers exchange Hello packets to establish neighbor relationships. The Hello packet sending modes vary by network type. On which of the following types of networks are Hello packets multicast?
Correct Answer: C,D
Comprehensive and Detailed In-Depth Explanation: OSPF usesHello packetsto establish and maintain neighbor relationships. The method of sending Hello packets depends on thenetwork type: Broadcast networks(e.g., Ethernet) usemulticast (224.0.0.5)to discover and maintain OSPF neighbors. Point-to-Point (P2P) networks(e.g., PPP links) also usemulticast (224.0.0.5)for Hello packet exchange. Non-Broadcast Multi-Access (NBMA) networks(e.g., Frame Relay) requiremanual neighbor configurationand useunicast Hello packetsinstead of multicast. Point-to-Multipoint (P2MP) networkscan send Hello packetseither unicast or multicast, but it depends on configuration. #Reference:Huawei HCIA-Datacom Study Guide, OSPF Neighbor Discovery and Hello Packet Mechanism.
H12-821_V1.0 Exam Question 119
When receiving a packet, a Huawei router matches the packet against ACL rules. The default ACL matching order used by the Huawei router is.
Correct Answer:
Sequential Explanation: ACL Matching in Huawei Routers: Access Control Lists (ACLs) are used to filter packets based on specific criteria, such as source/destination IP, ports, or protocols. When a packet arrives, the Huawei router processes it against the configured ACL rules to decide whether to permit or deny the packet. Reference: HCIP-Datacom-Core Technology Training Material (ACL Principles and Configuration). Sequential Matching Order: By default, Huawei routers match packets against ACL rules sequentially. This means: The router checks the packet against rules in the order they are listed, starting from the top of the ACL. The first rule that matches the packet's attributes is applied, and no further rules are checked. This is known as the first-match principle. If no rules match, the packet is denied by default (implicit deny). Reference: HCIP-Datacom Advanced Routing & Switching Technology (ACL Matching Mechanism). Example of Sequential Matching: Consider the following ACL rules: Rule 10: Permit IP 192.168.1.0/24 Rule 20: Deny IP 192.168.1.1 If a packet with source IP 192.168.1.1 arrives: The router matches it against Rule 10 (Permit 192.168.1.0/24) and allows the packet. Rule 20 is not evaluated because the first match (Rule 10) already applies. Alternative Matching Orders: Some routers or configurations allow batch matching (evaluating all rules) for specific scenarios, but this is not the default behavior in Huawei routers. Conclusion: The default ACL matching order on Huawei routers is sequential, and the first matching rule determines the action applied to the packet.
H12-821_V1.0 Exam Question 120
GRE is a VPN technology that can implement packet transmission over heterogeneous networks. Which of the following statements are true about GRE?
Correct Answer: C,D
Comprehensive and Detailed Step-by-Step Explanation: 1. What is GRE (Generic Routing Encapsulation)? * GRE is a tunneling protocol that allows the encapsulation of various types of packets (e.g., IPv4, IPv6, multicast, etc.) to be transmitted over another protocol (e.g., IP). * GRE is used to create point-to-point connections over heterogeneous networks. 2. Analysis of Each Option: Option A: GRE is a Layer 2 VPN encapsulation technology. * Incorrect. * GRE operates at Layer 3 (Network Layer) and encapsulates Layer 3 packets. It is not a Layer 2 VPN encapsulation technology like MPLS or Ethernet-over-IP. Option B: GRE enables encapsulated data packets to be transmitted over another network layer protocol, but cannot encapsulate multicast data. * Incorrect. * GRE supports the encapsulation and transmission of multicast data packets. This is one of its key features, making it suitable for protocols like OSPF and multicast applications. Option C: GRE tunnels can work with IPsec to ensure the security of multicast services such as voice and video. * Correct. * GRE by itself does not provide encryption or security. However, GRE can work with IPsec to secure the encapsulated traffic, including multicast data, for services like voice and video. Option D: GRE tunnels can extend the working range of network protocols with hop limits. * Correct. * GRE encapsulates packets, effectively resetting their hop limits and allowing protocols with limited hop counts (e.g., RIP) to work over larger networks. 3. Summary: * The correct options are C and D. Reference: Huawei HCIA-Datacom Study Guide, Chapter "GRE Tunnel Technology." RFC 2784: Generic Routing Encapsulation (GRE).
