User's Manual

Components 549
The drop down-menu at the top of this dialog box lists all the Layer 3
switches on which the new VLAN is to be created. See “
Reference C” on
page 576
for a list of devices which support VLAN-based IP routing
interfaces. If the previously selected switches do not include a Layer 3
switch, this dialog box will not be displayed and instead an error message
will be shown. In this situation, if you still want to add an IP interface, you
will have to add a Layer 3 switch to the list of switches on which the
VLAN is to be created. You can do this by stepping back in the wizard to
the “
Modifying the list of selected switches and ports” stage, described
on page 553
.
To specify an IP interface, select the Layer 3 switch on which the IP
interface is to be created from the drop-down menu and then enter a
unique IP address and a subnet mask. Some 3Com Layer 3 switches allow
you to create multiple IP interfaces per VLAN and as a result have the
concept of primary and secondary IP interfaces - see “
Primary and
Secondary IP interfaces” on page 506 for details. If your Layer 3 switch
supports this, the drop-down menu at the bottom of the dialog box can
be used to specify whether an IP interface is to be primary or secondary.
The first time an IP interface is specified for a VLAN on a particular device,
this drop-down menu will be pre-set to Primary and cannot be modified.
If you then launch the dialog box again to add another IP interface to the
same device, you will be able to choose whether the interface is to be
primary or secondary. By default, the field will be set to Secondary.
Clicking the OK button in the Add IP Routing Interfaces dialog box adds
the new IP interface to the table in the wizard stage: