|
CommView for
WiFi is capable of capturing data from multiple channels
simultaneously if one uses multiple compatible USB adapters. The
following 802.11n USB adapters can be used for multi-channel
capturing: D-Link DWA-160 v.A1, v.A2, v.B2, and v.C1, Edimax
EW-7733UnD, Linksys AE3000, NETGEAR WN111 v2, NETGEAR WNDA3100 v1,
Proxim ORiNOCO 8494, SMC Networks SMCWUSB-N2, Sony UWA-BR100,
TP-Link TL-WDN3200, TP-Link TL-WN721N, TP-Link TL- WN722N, TP-Link
TL-WN821N v1, v2, and v3, TP-Link TL-WN822N v1 and v2, Ubiquiti
SR71-USB, and CACE Technologies AirPcap Ex or NX. The following
802.11ac USB adapters can be used for multi-channel capturing:
Belkin F9L1109 v1, D-Link DWA-180 rev A1, D-Link DWA-182 rev C1,
Edimax EW-7822UAC, EnGenius EUB1200AC, Linksys WUSB6300, TP-LINK
Archer T4U, TRENDnet TEW-805UB, and ZyXEL AC240.
Note that
different types of adapters cannot be mixed; all of the adapters
should be of the same model. When multiple adapters are connected,
the following interface elements are changed:
|
·
|
The channel selection
control on the Capture
pane allows
you to select multiple channels. You can select multiple channels
by holding the Ctrl
key. The
number of channels that you select cannot exceed the number of
plugged in USB adapters. |
|
·
|
The Channel
Indicator pane displays multiple
indicators, the number of which is equal to the number of plugged
in USB adapters. |
|
This is
illustrated on the screen shot.
When using
multiple adapters, please consider the following:
1.
Power consumption. A single adapter might
need up to 450 mA of power. A single USB 2.0 port can provide up to
500 mA. A single USB 3.0 port can provide up to 900 mA. A typical
modern laptop has two USB 3.0 ports, so you should either use one
adapter per port, or you can use a USB hub, but if you plug in thee
adapters into a USB 3.0 hub, you will exceed the 900 mA limit,
which might cause undesirable effects, e.g. the adapters might stop
capturing packets silently.
2.
Channel switching time. When CommView for WiFi
is working in scanner mode, switching channels takes some time,
between 20 and 80 milliseconds per adapter. Consider a scan of 12
channels with the scanner interval of 250 ms per channel and the
channel switch time of, say, 60 ms. The total time would be (250 +
60) * 12 = 3.72 seconds if you use a single adapter. If you use
three adapters, the total time would be (250 + 60 *3) * 4 = 1.72
seconds. That is x2.16 times better, not x3 times better. Thus,
adding adapters adds channel switching overhead. If you use 12
adapters, which is possible in theory, it will take 250 + 60 * 12 =
0.97 seconds to scan 12 channels, so you're not gaining
much.
That said, we
don't recommend using more than two or three adapters.
|
|
|
