Planet WSD-800 User Manual page 47

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.
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.
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
User's Manual of WSD-800 / WGSD-910/WGSD-1022C
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