NETGEAR GS748TS-100NAS, GS748TNA user manual Appendix B Virtual Local Area Networks VLANs

Appendix B

Virtual Local Area Networks (VLANs)

A Local Area Network (LAN) can generally be defined as a broadcast domain. Hubs, bridges or switches in the same physical segment or segments connect all end node devices. End nodes can communicate with each other without the need for a router. Routers connect LANs together, routing the traffic to the appropriate port.

A virtual LAN (VLAN) is a local-area network with a definition that maps workstations on some other basis than geographic location (for example, by department, type of user, or primary application). To communicate between VLANs, traffic must go through a router, just as if they were on two separate LANs.

A VLAN is a group of PCs, servers and other network resources that behave as if they were connected to a single, network segment—even though they may not be. For example, all marketing personnel may be spread throughout a building. Yet if they are all assigned to a single VLAN, they can share resources and bandwidth as if they were connected to the same segment. The resources of other departments can be invisible to the marketing VLAN members, accessible to all, or accessible only to specified individuals, depending on how the IT manager has set up the VLANs.

The Advantages of VLANs:

•Easy to do network segmentation: Users that communicate most frequently with each other can be grouped into common VLANs, regardless of physical location. Each group's traffic is largely contained within the VLAN, reducing extraneous traffic and improving the efficiency of the whole network.

•Easy to manage: The addition of nodes, as well as moves and other changes, can be dealt with quickly and conveniently from a management interface rather than from the wiring closet.

•Increased performance: VLANs free up bandwidth by limiting node-to-node and broadcast traffic throughout the network.

•Enhanced network security: VLANs create virtual boundaries that can only be crossed through a router. So standard, router-based security measures can be used to restrict access to each

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Virtual Local Area Networks (VLANs) B-1

v2.0, April 2007