Why do VLANs 10 and 100 remain after the command erase startup-config is executed?

Why do VLANs 10 and 100 remain after the command erase startup-config is executed?

• A. They are saved in the running-config
• B. They are stored in a file called vlan.dat in flash memory
• C. They are automatically recreated by the switch
• D. They are part of the default configurations that cannot be deleted

Answer: (B)

When the command to erase the startup configuration is executed on a switch, it typically removes the configuration settings saved in the startup-config file located in NVRAM. However, VLANs are not stored in the startup configuration by default; instead, they have a separate storage mechanism. VLANs are maintained in a file named vlan.dat, which resides in flash memory. This file is specifically dedicated to storing VLAN information, separate from the running configuration or the saved startup configuration. Therefore, even after the startup configuration is erased, the VLANs defined in vlan.dat will remain intact. When the switch is rebooted, it reads the vlan.dat file to load the VLAN information, ensuring that VLANs 10 and 100 continue to exist. The other options do not accurately reflect how VLAN data is managed in a switch. The running configuration may hold current operational states but does not persist after a reboot unless saved. VLANs are not automatically recreated by the switch unless specifically configured, and they are not part of a default configuration that is immutable. Thus, the accurate understanding of VLAN management leads to the conclusion that they are stored in vlan.dat, which is why they remain after the startup configuration is erased.

When the command to erase the startup configuration is executed on a switch, it typically removes the configuration settings saved in the startup-config file located in NVRAM. However, VLANs are not stored in the startup configuration by default; instead, they have a separate storage mechanism.

VLANs are maintained in a file named vlan.dat, which resides in flash memory. This file is specifically dedicated to storing VLAN information, separate from the running configuration or the saved startup configuration. Therefore, even after the startup configuration is erased, the VLANs defined in vlan.dat will remain intact. When the switch is rebooted, it reads the vlan.dat file to load the VLAN information, ensuring that VLANs 10 and 100 continue to exist.

The other options do not accurately reflect how VLAN data is managed in a switch. The running configuration may hold current operational states but does not persist after a reboot unless saved. VLANs are not automatically recreated by the switch unless specifically configured, and they are not part of a default configuration that is immutable. Thus, the accurate understanding of VLAN management leads to the conclusion that they are stored in vlan.dat, which is why they remain after the startup configuration is erased.