PLANET GSW-1602SF - Manual (Page 61)

User’s Manual of GSW-1602SF / GSW-2404SF
4.6 VLAN
„ VLAN Overview
A Virtual LAN (VLAN) is a logical network grouping that limits the broadcast domain. It allows you to isolate network traffic
so only members of the VLAN receive traffic from the same VLAN members. Basically, creating a VLAN from a switch is
logically equivalent of reconnecting a group of network devices to another Layer 2 switch. However, all the network devices
are still plug into the same switch physically.
The Gigabit Ethernet Switch supports IEEE 802.1Q (tagged-based) and Port-Base VLAN setting in web management
page. In the default configuration, VLAN support is “802.1Q”.
„ Port-based VLAN
Port-based VLAN limit traffic that flows into and out of switch ports. Thus, all devices connected to a port are members of
the VLAN(s) the port belongs to, whether there is a single computer directly connected to a switch, or an entire department.
On port-based VLAN.NIC do not need to be able to identify 802.1Q tags in packet headers. NIC send and receive normal
Ethernet packets. If the packet's destination lies on the same segment, communications take place using normal Ethernet
protocols. Even though this is always the case, when the destination for a packet lies on another switch port, VLAN
considerations come into play to decide if the packet is dropped by the Switch or delivered.
„ IEEE 802.1Q VLANs
IEEE 802.1Q (tagged) VLAN are implemented on the Switch. 802.1Q VLAN require tagging, which enables them to span
the entire network (assuming all switches on the network are IEEE 802.1Q-compliant).
VLAN allow a network to be segmented in order to reduce the size of broadcast domains. All packets entering a VLAN will
only be forwarded to the stations (over IEEE 802.1Q enabled switches) that are members of that VLAN, and this includes
broadcast, multicast and unicast packets from unknown sources.
VLAN can also provide a level of security to your network. IEEE 802.1Q VLAN will only deliver packets between stations
that are members of the VLAN. Any port can be configured as either tagging or untagging:
„ The untagging feature of IEEE 802.1Q VLAN allows VLAN to work with legacy switches that don't recognize
VLAN tags in packet headers.
„ The tagging feature allows VLAN to span multiple 802.1Q-compliant switches through a single physical
connection and allows Spanning Tree to be enabled on all ports and work normally.
Some relevant terms:
„ Tagging - The act of putting 802.1Q VLAN information into the header of a packet.
„ Untagging - The act of stripping 802.1Q VLAN information out of the packet header.
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