3Com 1100 - Manual (Page 167)

VLANs and Your Switch 167
To create an 802.1Q tagged link:
1 Ensure that the device at the other end of the link uses the same 802.1Q
tags as your Switch.
2 Place the Switch port in the required VLANs using the VLAN Setup page
of the web interface; see “Placing Ports in Multiple VLANs Using 802.1Q
Tagging” on page 85 .
3 Place the port at the other end of the link in the same VLANs as the port
on your Switch.
You cannot create an 802.1Q tagged link with ports that already use VLT
tagging (see
“VLT Tagging” below).
VLT Tagging
This method of tagging is a proprietary system developed by 3Com, and
allows a link to carry traffic for all the VLANs defined on your Switch. VLT
tagging can only be used on links to legacy 3Com devices.
To create a VLT tagged link:
1 Specify that the port is a VLT port using the VLT listbox on the Port Setup
page of the web interface; see “Configuring a Port” on page 59 .
2 Specify that the port at the other end of the link is a VLT port.
You cannot create a VLT tagged link with ports that already use 802.1Q
tagging.
A VLT tagged link only carries traffic for VLANs defined on your Switch. In
legacy 3Com devices, a VLT tagged link carries traffic for all VLANs
automatically.
Using IEEE 802.1Q
Learning
If an endstation supports IEEE 802.1Q, it can be configured to inform
your network that it is to receive traffic for specific VLANs. If your Switch
units have IEEE 802.1Q learning enabled, they can do the following:
■
Automatically place the endstation in those VLANs.
■
Automatically ensure that the required VLAN traffic can always reach
the endstation from anywhere in the network.
IEEE 802.1Q VLAN Learning (GVRP) only works correctly in networks that
have 16 or less 802.1Q VLANs.