Huawei H12-811_V1.0 - HCIA-Datacom V1.0 Exam

Comprehensive and Detailed Explanation:

The history-command max-size command in Huawei VRP (Versatile Routing Platform) is used to set the maximum number of previously used commands that can be saved in the command history buffer.

By default, Huawei devices store 5 previously-used commands in the buffer.

The command history-command max-size 20 increases the buffer size to 20 commands.

This does not limit the buffer to 20 bytes; instead, it allows 20 entire commands to be stored.

The correct statement that matches this behavior is:

"The history-command max-size 20 command sets the maximum of previously-used commands that can be saved in the buffer to 20."

✅ Reference: HCIA-Datacom Configuration Guide – Command Line Interface

SNMP Agent Functionality:Each network device running SNMP includes an agent process that collects and manages information about the device's operations. This process interfaces with the SNMP manager to provide network monitoring and management capabilities​​.

Comprehensive Explanation: WEP (Wired Equivalent Privacy) is the only security policy in this list that supports open link authentication, which means no actual user credentials are required to associate with the network. WEP uses a shared key for encryption but offers minimal protection and is considered insecure. Other security methods like WPA, WPA2-PSK, and WPA2-802.1X use more secure forms of authentication, requiring credentials such as a password or centralized authentication server.

Given correct configuration, hosts within the same subnet should be able to communicate, so the host at 10.0.12.1 can ping the host at 10.0.12.2. This scenario assumes correct interconnectivity and absence of firewall or ACL rules that would block the communication​.

Detailed Explanation:Using DHCP provides several advantages:

It helps prevent IP address conflicts because the DHCP server dynamically assigns IP addresses, ensuring each device gets a unique one.

IP addresses can be reused by setting lease times, allowing the DHCP server to recycle addresses from devices that no longer need them.

Centralized configuration management is also possible. If network configuration details such as the DNS server change, the administrator can update these settings on the DHCP server, and all DHCP clients will automatically receive the new information​​.

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.

Tracert (Traceroute) works by sending packets with progressively higher TTL (Time-to-Live) values, causing them to expire at each router along the path. When TTL expires, the router sends back an ICMP "Time Exceeded" message, which includes the source IP address of that router. This allows Tracert to record the IP addresses of each router on the path to the destination​.

Detailed Explanation:In NAPT, port numbers are dynamically assigned as traffic flows through the router. The port number range is automatically selected, and manual configuration of each mapping is not required. NAPT dynamically uses different ports for mapping private IP addresses to a single public IP address​​.