User Manual

Wireless Topologies 26
As the mobile client seamlessly switches from cell to cell, its network connectivity is
preserved. The user can move freely between the Harmony 802.11a Access Points in
the network. When the roaming client leaves the transmission range of one 802.11a
Access Point, the software automatically polls the other 802.11a Access Point(s) in the
same Extended Service Set (ESS) to continue the network connection.
Note: The Access Points’ cells must overlap to ensure that there are no gaps in cov-
erage so that the roaming client will always have a connection available.
See Figure 3 for an example of a roaming Infrastructure network. In addition, if your
network has a Harmony Access Point Controllers, you can install Harmony 802.11a
Access Points on different IP subnets from the AP Controller, allowing mobile users to
roam across routers. For more information on the Harmony AP Controller and Access
Points, refer to the
Harmony Access Point Controller User’s Guide .
Guidelines for Roaming
• A Harmony 802.11a client can only roam between Harmony 802.11a Access
Points. An 802.11a client cannot communicate with Harmony 802.11b or OpenAir
Access Points.
• All Harmony 802.11a Access Points must have the same SSID.
• All workstations with Harmony 802.11a client adapters installed must use either
an SSID of “any” or the same SSID as the Access Points that they will roam
between.
• All 802.11a Access Points and clients must have the same security settings to
communicate.
• The Access Points’ cells must overlap to ensure that there are no gaps in coverage
and to ensure that the roaming client will always have a connection available.
• Access Points in the same vicinity should each use a unique, independent Chan-
nel to avoid potential interference.
• Access Points that use the same Channel should be installed as far away from
each other as possible to reduce potential interference.