VLAN

General Info

The switch port 24 needs to be plugged into the outside world. How the switch is configured to be a VLAN is detailed here: General_Network_Configuration_Notes

Here is an article on VLAN under Linux: Linux Journal

Configuration Files

From /usr/share/doc/initscripts-8.11.1/sysconfig.txt:

 /etc/sysconfig/network-scripts/ifcfg-<interface-name> and
 /etc/sysconfig/network-scripts/ifcfg-<interface-name>:<alias-name>:
   The first defines an interface, and the second contains
   only the parts of the definition that are different in a
   "alias" (or alternative) interface.  For example, the
   network numbers might be different, but everything else
   might be the same, so only the network numbers would be
   in the alias file, but all the device information would
   be in the base ifcfg file.

In-depth details here: Ifcfg_files_details