Installation guide

TD 92408EN
9 December 2011 / Ver. G
System Planning
Ascom VoWiFi System
9
Customer buys new APs for the n-radio and keeps the old a/b/g dual radio APs intact.
The customer adds n-supported APs across the complete site.
b/g old AP a old+new AP Comment
Voice +
data (legacy)
20 MHz only
Data(HT)
40 GHz only
DFS+non DFS
Greenfield
Turn off the a-radio in the a/b/g APs. This leaves the old AP
to s
upport only
b/g clients.
New APs set to use only the a-radio. HT only Greenfield
mo
de
.
Customer buys new APs for the n-radio and keeps the old a/b/g APs intact. Running
dual 5.0 GHz radios
b/g a Comment
-
Old AP
Data (legacy)
20 MHz only
New AP
Data (HT) DFS
Old AP
Voice -(no
HT),no
n-DFS,
20 MHz only.
This will allow the voice traffic to run on
the non-DFS
(Dynamic Frequency Selection) channels and the data
traffic to run on the DFS channels. See also, 802.11a Radar
Protection, Dynamic Frequency Selection (DFS) on pag
e
10.
2.2.4 Customer Has Already Invested in 802.11n Dual Band APs and Has Replace
d All
Old APs in the Same Position
In installations that support 802.11n from the beginning, or f
or a WLAN that has been
forklifted to support 802.11n, the following scenario may be relevant:
b/g/n a/n Comment
Legacy mode Legacy mode Customer runs the APs in legacy mode.
See above for possible combinations since in this case
802.
11n features are not turned on.
Voice +
data (legacy)
20 MHz only
Mixed mode
Data (HT),
40 MHz
Greenfield
The a/n radio is set for Greenfield mode only. Only H
T
c
lients accepted and no 20 MHz support.
Laptops may benefit from all enhancements in the
802.11n standard
like MIMO, dual bandwidth channels
etc.
Data (HT)
20 MHz only
Mixed mode
Voice (no HT)
20 MHz only
Mixed mode
Keep all data clients on the g/n radio. Laptops will
benefit fr
om all 802.11n enhancements except the use
of double bandwidth
channels, since the amount of
channels will be dramatically reduced.
Note: The VoWiFi Handset does not support either
Gr
eenfie
ld or 40 MHz modes.