Enterasys Vertical Horizon VH-2402S2, Руководство по настройке

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98 Virtual LANs (VLANs) VH-2402S2
VH-2402S2 VLAN Configuration
VLAN operation on the VH-2402S2 switch is enabled by default.
Therefore, all frames are transferred internally through a switch with a
VLAN tag. This tag may already be on the frame entering the switch, or
added to the frame by the switch. VLAN information already existing on
frames entering the switch is automatically handled by the switch. The
VH-2402S2 learns VLAN information from tagged frames and
appropriately switches frames out the proper ports based on this
information. The configuration of VLANs for frames entering the switch
without tags must be made by the user of the switch. This configuration
can be made either through the console interface or via SNMP.
Assigning Ports to VLANs
Before enabling VLANs for the switch, you must first assign each port to
the VLAN groups it will participate in. By default all ports are assigned to
VLAN 1 as untagged ports. You should add a port as a tagged port (that
is, a port attached to a VLAN-aware device) if you want it to carry traffic
for one or more VLANs and the device at the other end of the link also
supports VLANs. Then assign the port at the other end of the link to the
same VLANs. However, if you want a port on this switch to participate in
one or more VLANs, but the device at the other end of the link does not
support VLANs, then you must add this port as an untagged port (that is,
a port attached to a VLAN-unaware device).
Port-based VLANs are tied to specific ports. The switch’s forwarding
decision is based on the destination MAC address and its associated port.
Therefore, to make valid forwarding and flooding decisions, the switch
learns the relationship of the MAC address to its related port—and thus to
the VLAN—at run-time.
VLAN Classification
When the switch receives a frame, it classifies the frame in one of two
ways:
•
If the frame is untagged, the switch assigns the frame to an
associated VLAN based on the PVID of the receiving port.
•
If the frame is tagged, the switch uses the tagged VLAN ID to identify
the port broadcast domain of the frame.
Port Overlapping
Port overlapping can be used to allow access to commonly shared
network resources among different VLAN groups, such as file servers or
printers. Note that if you implement VLANs which do not overlap, but still
need to communicate, you must connect them using a router or Layer 3
switch.