Fortinet FortiGate FortiGate-100A, Руководство администратора

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FortiGate-100A Administration Guide 01-28006-0068-20041105
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VLAN overview
A VLAN is group of PCs, servers, and other network devices that communicate as if
they were on the same LAN segment, even though they may not be. For example, the
workstations and servers for an accounting department could be scattered throughout
an office, connected to numerous network segments, but they can still belong to the
same VLAN.
A VLAN segregates devices logically instead of physically. Each VLAN is treated as a
broadcast domain. Devices in VLAN 1 can connect with other devices in VLAN 1, but
cannot connect with devices in other VLANs. The communication among devices on a
VLAN is independent of the physical network.
A VLAN segregates devices by adding 802.1Q VLAN tags to all of the packets sent
and received by the devices in the VLAN. VLAN tags are 4-byte frame extensions that
contain a VLAN identifier as well as other information.
VLANs allow highly flexible, efficient network segmentation, enabling users and
resources to be grouped logically, regardless of physical locations.
Figure 14: Basic VLAN topology
VLAN Switch or router
Internet
VLAN 1
VLAN 2
VLAN 1 network VLAN 2 network
VLAN trunk
POWER
VLAN 1
VLAN 2
Firewall or
Router
Esc Enter
Untagged
packets