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Wi-Fi and Security Considerations for ClickShare

Page 5 of 14

IEEE802.11n access points can be operated in multiple

operational modes, each with advantages and disadvantages.

•

Mixed mode: enables 802.11n devices to co-exist and

interoperate with legacy 802.11b/g/a devices on the same

WLAN.

•

Legacy mode: makes the 802.11n AP behave like an

802.11g/a AP. There will be some performance

improvements due to some physical layer enhancements,

but the performance remains below full potential.

•

IEEE802.11n mode: this provides maximum performance

because the AP is not slowed down by more “air time”-

consuming legacy devices.

As stated above, the available channels vary according to the

various regions of the world. ClickShare obeys these

regulations and offers only those channels that are allowed in

the region identified on the product label (see bottom of Base

Unit, last 2 digits in the article number: e.g. NA for US and

Canada, EU for Europe, etc.).

But potential interference from neighboring channels must also

be considered. The 802.11 standard divides the frequency

bands (2.4GHz and 5GHz) into channels. The 2.4GHz range is

subdivided into 13 channels, each 22MHz wide and spaced

5MHz apart. These channels usually overlap one another,

resulting in signal degradation. As shown in the figure below,

there are only 3 non-overlapping channels available in the

IEEE802.11 standard: channel 1 with centre frequency

2.412GHz, channel 6 with centre frequency 2.437GHz, and

channel 11 with centre frequency 2.482GHz. Clearly, access

points located near each other must avoid overlapping

frequencies.

As we’ve said, a detailed description is beyond the scope of

this white paper. We provide a simplified view to illustrate the

OPERATIONAL

MODES

CHANNEL

SELECTION PER

REGION

1 2 3 4 5 6 7 8 9 10 ... 13 14

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Barco ClickShare Manuale Utente Pagina 5