42 lines
1.4 KiB
Markdown
42 lines
1.4 KiB
Markdown
Osmocom E1 recorder
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===================
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(C) 2016 by Harald Welte <laforge@gnumonks.org>
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The idea of this program is to be able to build a "poor mans E1/T1
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recorder" purposes of data analysis, *without* any special
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equipment.
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This approach is more risky than a purely passive, hardware based
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approach as that of the Osmocom e1-tracer released at
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https://osmocom.org/projects/e1-t1-adapter/wiki/E1_tracer
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If you can, it is strongly recommended to use the purely passive,
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high-impedance tap approach of e1-tracer and not the poor-man's
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software proxy approach presented in osmo-e1-recorder.
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Setup
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-----
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To do so, two E1 cards are used as some kind of proxy for the E1
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communication. Recording of a single E1 link always requires two E1
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interface cards, one for each direction.
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Recording can be performed either
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* passively, using a E1 Tap adapter
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* as a proxy / man-in-the-middle
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All timeslots will be opened in "raw" mode, making sure the recording
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will work whether or not there is HDLC-based signalling (MTP or LAPD),
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PCM voice, TRAU frames or anything else on the line.
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Recording will be done on a per-timeslot basis, dumping the raw bytes
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read for this timeslot into a file.
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New files are started regularly, after reaching a pre-determined file
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size limit. File names contain RTC time stamping and timeslot number.
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Later possible extensions could include automatic detection of the
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payload and a more intelligent storage format (e.g. in case of HDLC
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based signalling).
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