[Click] [click] How can roofnet run correctly on mode 11n

[Roberto Riggio]

Il 24/02/2011 09:45, 欧阳鑫 ha scritto:
> if ($mode =~ /n/) {
> $probes = "2 60 12 60 2 1500 4 1500 11 1500 22 1500 12 1500 18 1500 24 
> 1500 36 1500 48 1500 72 1500 96 1500 14.4 1500 28.8 1500 30 1500 43.4 
> 1500 57.8 1500 60 1500 86.6 1500 90 1500 115.6 1500 120 1500 130 1500 
> 144.4 1500 180 1500 240 1500 270 1500";
> } elsif ($mode =~ /g/) {
I think that the problem is here. Probes are not an 11n thing neither 
are they specific to the g or a variant. Probes
are send by roofnet to evaluate a link quality.

Specifically what you are telling roofnet is to send a series of probes 
using
different size and rate for each of them, for example for the 11g mode:

$probes = "2 60 12 60 2 1500 4 1500 11 1500 22 1500 12 1500 18 1500 24 
1500 36 1500 48 1500 72 1500 96 1500";

the line should be read like this

probe 1: [2 60] 60 bytes long probe sent at 1 mbps (2 / 2)
probe 2: [12 60] 60 bytes long probe sent at 6 mbps (12 / 2)
probe 3: [2 1500] 1500 bytes long probe sent at 1 mbps (2 / 2)

and so on.

In your probe list you have decimal numbers which are probably not 
valid. Moreover
the MCS rates are not specified using the rate itself but rather using 
an index according
to a table specified in the standard (but I think that you can easily 
find it online).

Finally, even putting the right index in the probe list would result in 
having that index
written to the radiotap "rate" field and not in the right MCS field to 
do this some extra
annotation are needed in click to match the new radiotap fields.


-- 
--------------------------------------------------------
Roberto Riggio, Ph.D.
CREATE-NET
Network&  Security Solutions for Pervasive Computing Systems (iNSPIRE)
Senior Researcher
Via alla Cascata 56/D - 38123 Povo Trento (Italy)
e-mail: roberto.riggio at create-net.org
Tel: (+39) 0461 408400 - interno/extension 708
Fax: (+39) 0461 421157
www.create-net.org/~rriggio
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