PLANET GSW-4804SF - Manual (Page 57)

User’s Manual of GSW-4804SF
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4.5.4 VLAN
This section provides VLAN Configuration and the available options are 802.1Q VLAN and Port-Based VLAN. Before use the
VLAN Configuration, please read following VLAN theorem completely before continuing.
VLAN Description
A Virtual Local Area Network (VLAN) is a network topology configured according to a logical scheme rather than the physical
layout. VLAN can be used to combine any collection of LAN segments into an autonomous user group that appears as a
single LAN. VLAN also logically segment the network into different broadcast domains so that packets are forwarded only
between ports within the VLAN. Typically, a VLAN corresponds to a particular subnet, although not necessarily.
VLAN can enhance performance by conserving bandwidth, and improve security by limiting traffic to specific domains.
A VLAN is a collection of end nodes grouped by logic instead of physical location. End nodes that frequently communicate
with each other are assigned to the same VLAN, regardless of where they are physically on the network. Logically, a VLAN
can be equated to a broadcast domain, because broadcast packets are forwarded to only members of the VLAN on which the
broadcast was initiated.
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Notice:
1. No matter what basis is used to uniquely identify end nodes and assign these nodes
VLAN membership, packets cannot cross VLAN without a network device performing a routing
function between the VLAN.
2. The Switch supports Port-based VLAN and IEEE 802.1Q VLAN. The port untagging function can be
used to remove the 802.1 tag from packet headers to maintain compatibility with devices that are
tag-unaware.
3. The Switch's default is to assign all ports to a single 802.1Q VLAN named DEFAULT_VLAN. As new
VLAN is created, the member ports assigned to the new VLAN will be removed from the DEFAULT_
VLAN port member list. The DEFAULT_VLAN has a VID = 1.
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.