Planet WGSW-2840 User Manual page 41

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 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.
Any port can be configured as either tagging or untagging. The untagging feature of IEEE 802.1Q VLAN
allow 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.
802.1Q VLAN Tags
The figure below shows the 802.1Q VLAN tag. There are four additional octets inserted after the source