Wireless Topologies

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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 on 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 that includes a Harmony Access Point Controller. A network that has one or more Harmony Access Point Controllers provides additional security and management features, such as AP Groups and the Harmony Security Protocol. In addition, 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 802.11a Access Points. An 802.11a client cannot communicate with Harmony 802.11b or OpenAir Access Points.

All 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.

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Harmony House 802.11a manual Guidelines for Roaming