Which command is used in Cisco IOS to create and enter VLAN configuration mode for VLAN 10?
Correct Answer: A
Detailed Explanation: In Cisco IOS, creating a VLAN and entering its configuration mode is typically performed using the "vlan" command followed by the VLAN ID. For example, entering "vlan 10" in global configuration mode will create VLAN 10 (if it does not already exist) and allow you to configure VLAN-specific parameters. This command is essential in network environments where segmentation is required to logically divide a larger broadcast domain into smaller, isolated segments. VLANs (Virtual LANs) are implemented to enhance network performance, improve security, and simplify network management. By creating separate VLANs, network administrators can segregate traffic based on function, department, or any other logical grouping, reducing broadcast traffic and preventing potential network congestion. The "vlan 10" command initiates this process by defining a new VLAN with an identifier of 10. When the command "vlan 10" is entered in global configuration mode, the router or switch enters VLAN configuration mode. In this mode, you can set various parameters specific to the VLAN, such as the VLAN name. For example, you might enter: vlan 10 name Sales_VLAN This configuration not only creates VLAN 10 but also assigns a descriptive name, making it easier to manage and identify within the network. It is important to note that this command is different from commands used to assign VLAN membership to switch ports. For instance, the command "switchport access vlan 10" (Option B) is used in interface configuration mode to assign a specific port to VLAN 10. However, creating the VLAN itself is accomplished with the "vlan 10" command. In many Cisco switches, especially older platforms or those using the VLAN database mode, there might be variations in how VLANs are created. However, on most modern Cisco devices running IOS, the standard method is to use the "vlan" command in global configuration mode. This method is straightforward and aligns with current best practices for VLAN configuration. Understanding how to create and manage VLANs is a key component of network segmentation and security. VLANs allow administrators to limit the scope of broadcast domains and enhance performance by reducing unnecessary traffic on individual segments of the network. Moreover, by isolating sensitive data or critical applications within specific VLANs, organizations can enhance their overall security posture. For those preparing for the CCNA exam, proficiency in VLAN configuration—including the proper use of the "vlan" command—is crucial. It not only demonstrates an understanding of how to logically segment a network but also prepares network professionals for more advanced tasks such as configuring inter-VLAN routing and troubleshooting VLAN-related issues. The ability to quickly and accurately configure VLANs is a core skill in managing modern switched networks. In summary, to create and enter VLAN configuration mode for VLAN 10 on Cisco IOS, you use the "vlan 10" command. This command is fundamental to VLAN management and plays a significant role in network segmentation, security, and performance optimization.
This CCNA practice question helps students prepare for Cisco networking certification exams by testing knowledge of network fundamentals, routing, switching, and network security concepts.