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

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.

Analysis of Possible Causes:

Option A: " The administrator account has been disabled " is a possible cause as a disabled account cannot access the system even if Telnet is enabled.

Option B: Incorrect because the Telnet service being disabled would affect all users, not just one administrator.

Option C: " The administrator account has been deleted " is a valid reason as a deleted account cannot log in.

Option D: " The user level of the administrator account has been changed to 0 " is correct. User level 0 typically has insufficient privileges for Telnet access​​.

Comprehensive and Detailed Explanation:

The TTL field is 8 bits long, allowing values from 0 to 255 (A is correct).

The TTL prevents routing loops by discarding packets with TTL=0 (B is correct).

Each Layer 3 device (router) that forwards the packet decrements TTL by 1 (C is correct).

If TTL reaches zero, the router drops the packet and sends an ICMP Time Exceeded message.

✅ Reference: HCIA-Datacom Network Principles Guide – IP Packet Structure

In Spanning Tree Protocol (STP), the Port ID consists of:

8-bit Port Priority

8-bit Port Number

This results in a total length of 16 bits.

B, C, and D are incorrect since they do not represent the full length of the Port ID.

Thus, the correct answer is A (16 bits).

Detailed Explanation:

Probe Request: Sent by the client to detect nearby APs.

Probe Response: Sent by APs in response to the client’s request.

Beacon: Periodically broadcast by APs to announce their presence and SSID. The Discovery packet type does not exist in the 802.11 standard.

(Reference: HCIA-WLAN Training Material, WLAN Packet Types)

A (Correct): The client initiates the connection using a random source port (50190).

B (Correct): The packets show the TCP three-way handshake (SYN, SYN-ACK, ACK).

C (Incorrect): The client initiates the connection (10.0.12.1), and the server responds (10.0.12.2), so the roles are reversed in this statement.

D (Correct): The handshake packets contain no application-layer data, only TCP control flags.

Thus, the correct answer is C (False Statement).

An ARP (Address Resolution Protocol) packet includes several fields essential for mapping IP addresses to MAC addresses. The fields include:

Source Protocol Address: Identifies the IP address of the requesting device.

Source Hardware Address: Contains the MAC address of the source.

Hardware Type: Indicates the hardware type, typically Ethernet.

Operation Code: Specifies the operation (request or reply). These fields collectively allow devices to resolve IP addresses to physical MAC addresses, enabling direct communication within the local network​.

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.

Comprehensive and Detailed Explanation:

OSPF neighbor states occur in the following sequence:

Down → No Hello packets received.

Init → Hello received, but no bidirectional communication yet.

2-Way → Bidirectional Hello exchange, DR/BDR election happens here.

ExStart → Master/slave relationship is determined (B is correct).

Exchange → Routers exchange Database Description (DD) packets to describe their LSDBs (A and D are correct).

Loading → Link State Requests (LSR) and Link State Updates (LSU) occur.

Full → LSDB synchronization is complete (C is correct).

✅ Reference: HCIA-Datacom Routing Guide – OSPF Neighbor States