3Com 3C15500 - Network Director - PC, User Manual

Page: 527 / 924

Components 523
VLAN IDs
This check box controls how VLANs are listed in the Show VLANs toolbar
and in the Find dialog box. When this check box is unchecked, 3Com
Network Director will list all discrete VLANs on the network map, even if
they use the same VLAN ID.
For example, consider a network map containing 10 unconnected remote
offices, each using VLANs with IDs 1 to 5. Because there is no connection
between the remote offices, 3Com Network Director will consider VLANs
with the same ID to be different VLANs. In this case, the
Show VLANs
toolbar would list 50 individual VLANs.
For some networks, this may not scale as the number of VLANs listed may
become unmanageable. This can be overcome by checking the
VLAN list
contain only one entry per VLAN ID check box in the Options dialog box.
This has the effect of only listing one entry in the Show VLANs toolbar
and Find dialog box for each unique VLAN ID.
So in the previous example, only 5 entries would be listed, for VLAN IDs 1
to 5. Selecting, say, VLAN ID 4 in the
Show VLANs toolbar would result in
all of the discrete VLANs using VLAN ID 4 being highlighted on the map.
With the check box unchecked, selecting one of the 10 entries for VLAN
ID 4 would have resulted in only one of the discrete VLANs being
highlighted.
VLAN membership
The radio buttons in this section allow you to control how the VLAN
membership is displayed when a VLAN is selected in the
Show VLANs
toolbar or the Find dialog box. With the Include only configured devices
option selected, only those switches and links on which the VLAN is
explicitly configured are displayed. With the
Include both configured and
inferred devices option selected, as well as showing the switches and
links on which the VLAN is configured, those devices and links that 3Com
Network Director has inferred are members of the VLAN will also be
displayed. See
“VLAN membership inference” on page 509 .
A change to any of the VLAN options will only take effect the next time
you launch the
Show VLANs toolbar or Find dialog box i.e. if the Show
VLANs toolbar is being displayed when a change is made to the VLANs
tab in the Options dialog box, these changes will not be immediately
reflected by the Show VLANs toolbar. The toolbar would have to be
closed and re-launched.