Re: Request for DECT LINKTYPE

[Matthias Wenzel <tcpdump () mazzoo de>]

Guy Harris wrote:
> On Dec 22, 2008, at 1:51 AM, Matthias Wenzel wrote:
>
> > we have a set of opensource tools that read and write pcap files from/to
> > DECT devices. The SW will go public still this year. We're working with
> > both gnuradio USRP and a dedicated HW.
>
> Could the code to capture DECT traffic go into libpcap?

Not as of now. We're not capturing from neiter a tun/tap device, nor a
network interface. For now we have a driver with a char device, some
ioctls and firmware.
In future we may implement a virtual network device within linux.

> > For what you may want to know there are basically 3 types of DECT out
> > there (from what I know):
> >
> > 1) DECT - the first real and widely used in europe and asia
> >
> > 2) DECT6.0 - a very new US variant, operating like 1) but slightly
> > different radio channels
> >
> > 3) US-DECT, aka WDCT - a 2.4GHz variant with channelhopping, all
> > differnt Layer 1 than 1) and 2)
> >
> > our HW, as probably most HW out there supports both 1) and 2),
> > but not 3).
> >
> > so you may want to reserve 2 LINKTYPE values, call them LINKTYPE_DECT
> > and LINKTYPE_USDECT or the like.
>
> So DECT and DECT 6.0 are close enough that they can use
> LINKTYPE_DECT/DLT_DECT?

Yes. DECT has 10 radio channels, DECT 6.0 has 5, they all fit into one
0-63 channel table scheme in ETSI EN 300 175-2, Annex F (mostly
unlicensed channels).

> And is "US-DECT" a US-specific scheme?
>
>     http://www.dectweb.com/LearningZone/WDCTTech.htm
>
> claims that the "W" in "WDCT" is "Worldwide", but also claims that it's
> US-specific.  (BTW, does "US" in this context mean "US and Canada" or
> "North America" rather than just the US?)

I cannot say what countries are covered by WDCT other than the US. Also
this standard is not part of our work. I just wanted to mention that
there's another variant out there, and you may want to keep them as
"neighbours" in the #define LINKTYPE_* set.
Legally WDCT can be run pretty much anywhere, as it lies in the 2.4GHz
ISM band. But that also is the reason for its failing success. There's
too much noise in 2.4GHz for having a robust cordless telephone.


best regards,

matthias
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