tcpdump mailing list archives
Re: Request for DECT LINKTYPE
From: Matthias Wenzel <tcpdump () mazzoo de>
Date: Tue, 23 Dec 2008 10:57:45 +0100
Guy Harris wrote:
On Dec 22, 2008, at 1:18 PM, Matthias Wenzel wrote:Guy Harris wrote: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).So what would the data in the packet start with? Would these be MAC-layer messages (possibly with some metadata)?
We currently start with metadata such as rx/tx mode, channel, timeslot, frame/multiframe number, RSSI value. Then follows the packet almost verbatim as seen on air, starting with a preabmle, packet type, payload and trailing CRCs. I wrote "almost verbatim" as our device already does some descrambling of parts of the payload.
So perhaps I'll just call it WDCT (that's what Siemens appears to call it, and they appear to be the ones who developed it), hence LINKTYPE_WDCT/DLT_WDCT.
good, but see below.
Are there any published specifications for it, or is that only specified in internal Siemens documentation?
Forget all I said about WDCT, it's all within the same standard ETSI EN 300 175. Now I had a look at that part of the standard, and all the standard defines is another set of channels in various ISM bands as 915MHz, 2.4GHz and 5.8GHz. The channelhopping story is not part of the standard but exists as proprietary manufacturer extensions. Otherwise one couldn't get any quality on those noisy ISM bands. As a result there's no interoperability between different manufacturer's phones and basestations in WDCT. We can't care too much about proprietary extensions, so I suggest just one LINKTYPE_DECT, and we'll add a metadata field for the band. best regards, matthias - This is the tcpdump-workers list. Visit https://cod.sandelman.ca/ to unsubscribe.
Current thread:
- Re: Request for DECT LINKTYPE, (continued)
- Re: Request for DECT LINKTYPE Guy Harris (Dec 22)
- Re: Request for DECT LINKTYPE Maciej Grela (Dec 22)
- Re: Request for DECT LINKTYPE Matthias Wenzel (Dec 22)
- Re: Request for DECT LINKTYPE ronnie sahlberg (Dec 22)
- Re: Request for DECT LINKTYPE Matthias Wenzel (Dec 22)
- Re: Request for DECT LINKTYPE Guy Harris (Dec 22)
- Re: Request for DECT LINKTYPE Matthias Wenzel (Dec 23)
- Re: Request for DECT LINKTYPE Guy Harris (Dec 23)
- Re: Request for DECT LINKTYPE Matthias Wenzel (Dec 23)
- Re: Request for DECT LINKTYPE Guy Harris (Dec 22)
- Re: Request for DECT LINKTYPE Guy Harris (Dec 22)
- Re: Request for DECT LINKTYPE Matthias Wenzel (Dec 23)