3Com MSH 1005, User Manual

Page: 104 / 155

DUA1840-0AAA01
Virtual LANs (VLANs) 4-13
Select Port Type Port/Backbone Port This field allows you to specify
whether the port specified in the Port ID field is a backbone port. A
backbone port is used to connect each VLAN to the backbone of your
network, and has the following attributes:
■
Addresses received on the port are not stored in the Switch
Database.
■
Frames with unknown addresses received by the Switch are
forwarded to the port.
Any port in a VLAN can be designated as the backbone port for that
VLAN, but you can only have one backbone port per VLAN. By default,
all ports belong to the Default VLAN (VLAN 1); because of this, an
unconfigured Switch module can only have one backbone port.
If the Switch 1005 has a Fast Ethernet Transceiver Module installed, this
automatically becomes the backbone port for the Default VLAN when
you initialize the Switch. If the Switch has more than one Fast Ethernet
Transceiver Module, the Transceiver Module with the lowest port
number automatically becomes the backbone port for the Default
VLAN. If the Switch has no Fast Ethernet Transceiver Module, but it uses
port 28 to connect to the Fast Ethernet backplane, port 28
automatically becomes the backbone port for the Default VLAN.
A listbox containing the following fields:
Port The port ID for the entry.
VLAN The ID of the VLAN(s) that the port belongs to.
VLT Shows * if the port forms part of a Virtual LAN Trunk (VLT). A
Virtual LAN Trunk is a connection which carries traffic for multiple
VLANs between Switch units. For more information about VLTs in
general, see “VLANs and the Switch 1005” on page 4-4 . To specify
that a port is a VLT, see “Port Setup” on page 3-7 .
BP The backbone port for the VLAN specified in the VLAN field.