Netgear FS728TLP Web Management User Guide - Page 308

ProSAFE FS526Tv2, FS726Tv2, and FS728TLP Smart Switches Virtual Local Area Networks 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 endnode 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 basis other than geographic location (for example, by department, type of user, or primary application). To enable traffic to flow between VLANs, traffic needs to go through a router, just as if the VLANs were on two separate LANs. A VLAN is a group of computers, servers, and other network resources that behave as if they were connected to a single network segment-even though they might not be. For example, all marketing personnel might 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. VLAN Advantages VLANs have a number of advantages: • It is easy to segment the network. Users who communicate most frequently with each other can be grouped into common VLANs, regardless of physical location. Each group's traffic is contained largely within the VLAN, reducing extraneous traffic and improving the efficiency of the whole network. • They are 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. • They provide increased performance. VLANs free up bandwidth by limiting node-to-node and broadcast traffic throughout the network. • They ensure enhanced network security. VLANs create virtual boundaries that can be crossed only through a router. So standard, router-based security measures can be used to restrict access to each VLAN. Packets that enter the smart switch are treated in the following way: • When an untagged packet enters a port, it is automatically tagged with the port's default VLAN ID tag number. Each port has a default VLAN ID setting that is user-configurable (the default setting is 1). You can change the default VLAN ID setting for each port on the Port PVID Configuration screen (select Switching > VLAN > Advanced > Port PVID Configuration; see also Configure Port VLAN IDs for Ports and LAGs on page 85). • When a tagged packet enters a port, the default VLAN ID setting does not affect the tag for that packet. The packet proceeds to the VLAN that is specified by its VLAN ID tag number. Configuration Examples 308