Specifications

5.7 VLAN Manager
Management Tools 5–11
5.7 VLAN Manager
VLAN Manager is a clearVISN application that runs on the Windows 95 or
Windows NT operating system. It enables you to logically segment your network
into virtual LANs (VLANs). A virtual LAN is a broadcast domain whose
membership is based on logical groupings instead of physical media connections.
This means that LAN membership can be defined by users’ communication needs to
rather than the physical connections of nodes and media. Members of a VLAN can
communicate as though they were connected to the same physical LAN.
You use Digital’s VLAN-capable switches connected over an FDDI backbone to
configure port-based VLANs. Port-based VLANs are collections of switch ports
which behave as a single broadcast domain. Digital’s port-based VLANs can consist
of ports from any switch connected by the FDDI backbone. A single Ethernet port on
a switch can only be assigned to one VLAN at a time. However, within one switch
each Ethernet port can be assigned to a different VLAN. Thus, not all Ethernet ports
on a switch to belong to the same VLAN. All the Ethernet ports across the switches
assigned to one VLAN make up that VLAN. Network traffic originating at any one
of the ports is forwarded across the FDDI backbone to all the other ports on a
particular VLAN. Therefore, membership of a particular VLAN is based solely on
access to ports on the switches. Digital’s DECswitch 900EF, DECswitch 900FO,
PEswitch 900TX switches with V1.6 firmware or later currently support port-based
VLANs.
You configure VLANs off-line using VLAN Manager. You then use VLAN
Manager, via SNMP, to load the VLAN configuration information into Digital’s
VLAN-capable switches immediately or at a later time. You can then perform
moves, adds, and changes to these VLANs without actually changing the physical
network cabling or manually manipulating network switching devices such as hubs
or switches. Instead, you simply modify the VLAN configuration that defines the
VLANs and reload it to the switches.
VLAN Manager is well suited for use with existing networks as well as networks
currently being designed and installed. Applying a VLAN configuration to an
existing network does not disrupt communication between users who are not
included in the created VLANs. Of course, non-VLAN users cannot communicate
with VLAN users, except through a router, just as users on one VLAN cannot
communicate with users on another created VLAN. However, communication
between non-VLAN users continues just as before. Thus, all non-VLAN users make
up a “default” VLAN. For new networks, the network configuration can be entered
in a VLAN database and evaluated before actually installing the network hardware.