At-Mux Protocol Overview - Allied Telesis AT-2700FX Installation Manual

Chapter 9: AT-MUX Multiple VLAN Protocol

AT-MUX Protocol Overview

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The AT-MUX protocol is useful in Ethernet networks where there are
tagged virtual LANs (VLAN). You can use the protocol to assign up to 16
VLAN identifiers (VID) to an adapter so that it can process and transmit
tagged traffic from multiple tagged VLANs.
Note
The AT-MUX protocol is supported on Microsoft Windows 2000,
2003, and XP systems only. The system must have the latest
Microsoft Windows 2000, 2003, or XP Ndis 5 driver (version 4.1.10).
As explained in "Virtual LANs and the AT-MUX Protocol" on page 37, a
VLAN is an independent traffic domain where traffic generated by the
nodes of a VLAN is restricted only to other nodes of the same VLAN.
Tagged traffic within a VLAN is identified by a header tag that follows the
source and destination addresses in a frame. The tag contains the VID
that identifies the VLAN to which the packet belongs.
With the AT-MUX protocol you can assign multiple VIDs to an adapter so
that the adapter can read the tag in tagged traffic that it receives as well as
add tags to traffic that it transmits. To configure the AT-MUX protocol, you
specify the VIDs of the VLANs whose traffic you want the adapter to
handle. For instance, assume that you had installed the adapter in a
server that will handle traffic from the following three VLANs:
Sales - VID 12
Sales Support - VID 14
Marketing - VID 25
In this example, you would use the AT-MUX protocol to add these three
VIDs to the adapter. Untagged packets and tagged Ethernet traffic from
VLANs other than these three would be discarded by the adapter.
For systems with multiple adapter cards, you must install the AT-MUX
protocol on each adapter that you want to support multiple VLANs. For
instance, if a system contained two adapters and you wanted both
adapters to handle tagged packets, you would install the utility on both
adapters.
Each VID and, consequently, each VLAN is considered a separate LAN
connection by the network adapter card. This is reflected in the Network
Connections window of the Microsoft Windows operating system. A new
LAN connection is added to the window for each new VLAN. The icon for a
VLAN connection is easily identified by the label "Allied Telesyn VLAN-
Tagging miniport Driver." (The easiest way to view this is by selecting the
Tile menu selection under the View menu in the Network Connections