User's Manual

DragonWave Inc. 32
AirPair 100 UL 24 GHz Product Manual
4.7. VLAN tagging
A Local Area Network (LAN) is a single-broadcast domain. If a user broadcasts
information on the LAN, every other user on the LAN receives the broadcast. A
router prevents broadcast messages from leaving a LAN, which reduces
collisions and improves performance.
A network manager can create smaller broadcast domains and reduce network
broadcasts by logically segmenting a LAN into different broadcast domains.
These broadcast domains are called Virtual Local Area Networks (VLANs).
Workstations on a VLAN do not have to be located together because they are
segmented logically, not physically.
VLANs offer a number of advantages over traditional LANs including:
• Performance
• Security
• formation of virtual workgroups
• cost reduction
All ports on a switch are configured for a default VLAN (usually VLAN1). When a
switch receives data from a workstation, it tags the data with a VLAN identifier
indicating the originating VLAN. The switch sends the data to the ports inside the
VLAN where it originated. It also sends the data to a trunking port if one is
available.
Network Administrators create VLAN groups and place backbone network
devices into the VLAN group to simplify administration and increase security of
the devices. VLAN tagging allows network administrators to add AirPair nodes to
the administrative network. VLAN tagging restricts administrative access to
devices that are members of the VLAN group.
If you program an AirPair node with an IP address but do not enable VLAN
tagging, the node responds to Ping, Telnet and SNMP commands from any
device on the network. Telnet and SNMP require a username and password, the
proper IP address and community string, respectively.
If you enable VLAN tagging, the AirPair nodes respond to ping commands but do
not respond to Telnet and SNMP commands unless the packet has the correct
VLAN tag. The Telnet and SNMP requests must have the correct VLAN tag and
come from a device within the VLAN domain.
The Institute of Electrical and Electronic Engineers (IEEE) is working on a draft
standard 802.1Q for VLANs. Currently, most products are proprietary and
anyone wanting to install VLANs has to purchase all products from the same
vendor. DragonWave implements AirPair VLAN Tagging using the 802.1Q
standard. For more information on the Standard, see the web page:
http://grouper.ieee.org/groups/802/1/pages/802.1Q.html