Allied Telesis AT-8550 - Manual (Page 74)

Types of VLANs
4-8
As data passes out of the switch, the switch determines if the
destination port requires the frames to be tagged or untagged. All
traffic coming from and going to the server is tagged. Traffic coming
from and going to the trunk ports is tagged. The traffic that comes
from and goes to the other stations on this network is not tagged.
Mixing Port-based and Tagged VLANs. You can configure the
switch using a combination of port-based and tagged VLANs. A
given port can be a member of multiple VLANs, with the stipulation
that only one of its VLANs uses untagged traffic. In other words, a
port can simultaneously be a member of one port-based VLAN and
multiple tag-based VLANs.
Note
For the purposes of VLAN classification, packets arriving on a port
with an 802.1Q tag containing a VLANid of zero are treated as
untagged.
Generic VLAN
Registration
Protocol
The Generic VLAN Registration Protocol (GVRP) allows a LAN device
to signal other neighboring devices that it wishes to receive packets
for one or more VLANs. The GVRP protocol is defined as part of the
IEEE 802.1Q Virtual LANs draft standard. The main purpose of the
protocol is to allow switches to automatically discover some of the
VLAN information that would otherwise have to be manually
configured in each switch. GVRP can also be run by network servers.
These servers are usually configured to join several VLANs, and then
signal the network switches of the VLANs of which they want to be
part.
Figure 4-6 illustrates a network using GVRP.
Figure 4-6 Network Example Using GVRP
VLAN Red,
Untagged
VLAN Red,
Untagged
Switch A VLAN Red, Tag 10
Switch B
GVRP: "Send
me traffic for
VLAN tag 10."
GVRP: "Send
me traffic for
VLAN tag 10."
GVRP: "Send
me traffic for
VLAN tag 10."
POWER MGMT.
10/100BASE-T ETHERNET SWITCH
WITH GIGABIT ETHERNET
LINK ON ACTIVITY DISABLED 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 25 25R 25R A L 25 25R
1000BASE-X 10/100BASE-TX MDI-X