Siemens SCALANCE W1780 Configuration Manual page 16

Description
2.1 Network structures
Wireless access to a wired Ethernet network
If one (or more) access points have access to wired Ethernet, the following applications are
possible:
● A single device as gateway:
A wireless network can be connected to a wired network via an access point.
● Span of wireless coverage for the wireless network with several access points:
The access points are all configured with the same unique SSID (network name). All nodes
that want to communicate over this network must also be configured with this SSID.
If a mobile station moves from the area covered by one access point to the area covered by
another access point, the wireless link is maintained (roaming).
The following graphic shows the wireless connection of a mobile station over two wireless
cells (roaming).
Multichannel configuration
If neighboring access points use the same frequency channel, this can lead to longer response
times due to any collisions that may occur. If the configuration shown in the figure is
implemented as a single-channel system, computers A and B cannot communicate at the same
time with the access points in their wireless cells.
If neighboring access points are set up for different frequencies, this leads to a considerable
improvement in performance. As a result, neighboring wireless cells each have their own
medium available and the delays resulting from time-offset transmission no longer occur.
The channel spacing should be as large as possible; a practical value is 25 MHz. Even in a
multichannel configuration, all access points can be configured with the same network name.
The following graphic shows a multichannel configuration on channels 1 and 2 with four access
points.
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SCALANCE W1780/W1740 according to IEEE 802.11ac Web Based Management
Configuration Manual, 11/2019, C79000-G8976-C485-03