User guide

Designing Your Canopy Network March 2005
Through Software Release 6.1
Issue 1 Page 125 of 425
Canopy System User Guide
14 ENGINEERING VLANS
In Canopy System Release 6.0 and later releases, Canopy radios support VLAN
functionality as defined in the 802.1Q specification, except for the following aspects of
that specification:
◦ the following protocols:
− GARP GARV
− STP
− MSTP
− GARP GMRP
◦ priority encoding (802.1P)
◦ embedded source routing (ERIF) in the 802.1Q header
◦ multicast pruning
◦ flooding unknown unicast frames in the downlink
As an additional exception, the Canopy AP does not flood downward the unknown
unicast frames to the Canopy SM.
A VLAN configuration in Layer 2 establishes a logical group within the network. Each
computer in the VLAN, regardless of initial or eventual physical location, has access to
the same data. For the network operator, this provides flexibility in network segmentation,
simpler management, and enhanced security.
With the supported VLAN functionality, Canopy radios determine bridge forwarding on
the basis of not only the destination MAC address, but also the VLAN ID of the
destination. This provides flexibility in how SMs are used:
◦ Each SM can be a member in its own VLAN, whose other members can be APs
in other sectors. This case would allow movement of the SM from sector to
sector without requiring a reconfiguration of the VLAN.
◦ Each SM can be in its own broadcast domain, such that only the radios that are
members of the VLAN can see multicast traffic to and from the SM. In most
cases, this can significantly conserve bandwidth at the SMs.
◦ The network operator can define a work group of SMs, regardless of the AP in
which they register.