D-Link DES-3624 - Switch - Stackable User manual - Ieee 802.1Q Vlans
Stackable NWay Ethernet Switch User’s Guide
IEEE 802.1Q VLANs
The Switch supports up to 96 IEEE 802.1Q (port-based)
VLANs. Port-based VLANs 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 VLANs, NICs do not need to be able to identify
802.1Q tags in packet headers. NICs 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 gets
dropped by the switch or delivered.
There are two key components to understanding IEEE 802.1Q
VLANs; Port VLAN ID numbers (PVID) and VLAN ID numbers
(VID). Both variables are assigned to a switch port, but there
are important differences between them. A user can only
assign one PVID to each switch port. The PVID defines which
VLAN a switch will forward packets from the connected
segment on, when packets need to be forwarded to another
switch port or somewhere else on the network. On the other
hand, a user can define a port as a member of multiple VLANs
(VIDs), allowing the segment connected to it to receive packets
from many VLANs on the network. These two variables control
a port’s ability to transmit and receive VLAN traffic, and the
difference between them provides network segmentation, while
still allowing resources to be shared across more than one
VLAN.
Switch Management Concepts
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