Netgear FVS318N – Prosafe Wireless N VPN Firewall 参照マニュアル

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LAN Configuration
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ProSAFE Wireless-N 8-Port Gigabit VPN Firewall FVS318N 
Manage IPv4 Virtual LANs and DHCP Options
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. 
Endpoints 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, 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.
VLANs have a number of advantages:
It is easy to set up network segmentation. 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.