It’s fairly easy to create a VLAN with a switch. Just Telnet into the switch and enter your VLAN parameters (name, domain, port assignments, etc). Once you’ve applied all that, your VLAN is set up and any network segments connected to the assigned ports will be part of that VLAN.
You can have more than one VLAN on a switch, but they cannot communicate directly with one another on that switch. This is important. If VLANs could communicate with each other on the same switch, it would defeat the purpose of having a VLAN, which is to isolate a part of the network. If you want your VLANs to communicate, you’ll usually need to get another switch (an exception would be that “router-on-a-stick” setup).
However, VLANs need not be tied to a single switch. VLANs can span across multiple switches, or you can have more than one VLAN on each switch. For multiple VLANs on multiple switches to be able to communicate via a single link between the switches, you must use a process called “trunking.” Trunking is the technology that allows information from multiple VLANs to be carried over just one link between switches.
Switches communicate with each other about VLAN configuration via the VLAN Trunking Protocol (VTP). Another protocol to remember is Dynamic Trunking Protocol (DTP). DTP is what Cisco switches use to manage trunk negation in the Catalyst-switch engine’s software, release 4.2 or later. DTP supports ISL and 802.1Q. DTP was developed to send trunk information across 802.1Q trunks.
Cramsession
InfoCenter Article: Segmenting a LAN with VLANs Part I
Cramsession
InfoCenter Article: Segmenting a LAN with VLANs Part II
Intel’s
VLAN page
Network attached storage is what many network administrators are using to replace file servers. File servers, which store files and make those files available to client users, are often the most frequently accessed servers on a network. They are usually heavy-duty computers, often running specialized software. File servers can cost several thousand dollars.
Network Attached Storage units are smaller network devices (sometimes called “black boxes”), with a NIC, a large hard disk drive, and not much else. They usually run a special, proprietary operating system. Aside from these odd (compared to traditional) characteristics, a Network Attached Storage device is otherwise just a file server. What it is, by comparison (and this is always attractive to bottom-line-obsessed network administrators' bosses), is cheap. A decent file server (say a Pentium II with 256 MB RAM and a multiple hot-swap HDD array) could run several thousand but a 20GB Network Attached Storage device may cost only a few hundred.
These devices are also easy to manage. Security and access are easy to configure. It also takes only minutes to set up a Network Attached Storage device, compared to the several hours it takes for issue-free server installation (and you know there are ALWAYS issues).
IBM’s
Network Attached Storage Devices
Iomega’s Network Attached
Storage Devices
Kintronics Network
Attached Storage Overview