diff README @ 29:dffcae9bc8a3

add README
author Mychaela Falconia <falcon@freecalypso.org>
date Sat, 02 Jul 2022 11:17:11 -0800
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+This Hg repository contains a work-in-progress named Themyscira Wireless system
+software.  Themyscira Wireless (ThemWi) is an experimental GSM network operated
+by Mother Mychaela of FreeCalypso at a semi-urban/semi-rural location in
+Southern California, USA; this GSM network is operated with Osmocom CNI software
+components, all running on a single Slackware Linux server.  ThemWi system sw
+is going to be a suite of daemon processes and command line tools that run on
+the same machine as all those Osmocom sw components and provide some additional
+functionality that is not provided "out of the box" by Osmocom, most important
+of which is outside connectivity to USA PSTN.
+
+Right now we have a themwi-mncc daemon process that connects to OsmoMSC via the
+MNCC socket interface provided by the latter and takes the place of OsmoMSC's
+mncc_builtin.  themwi-mncc switches local calls (from one GSM subscriber to
+another) just like mncc_builtin, but it also provides a hook (mtcall_socket)
+for routing externally originated calls to GSM (which then become MT calls),
+and it will later have a similar interface for routing MO calls to the outside
+world.  Additional daemon processes that will interface with USA PSTN via SIP
+(one process accepting SIP INVITEs from bulkvs.com servers, turning them into
+MNCC and sending the calls toward GSM, and another process going the other way)
+remain to be implemented.
+
+We are currently experimenting with using bulkvs.com as our USA PSTN
+connectivity provider.  Like most low-cost PSTN connectivity providers, they
+provide the interface to PSTN in the form of a SIP trunk - while I would
+absolutely love to get a traditional TDM trunk instead, with SS7 signaling,
+such a toy would be far beyond my budget, hence I have to settle for SIP.
+Our current status is:
+
+* We have already obtained a block of USA phone numbers (NANP, chosen numbers
+  from an exchange area local to us) from bulkvs.com;
+
+* These bulkvs-sourced real NANP numbers have been entered as MSISDNs into
+  OsmoHLR records for our test SIMs operating on ThemWi GSM;
+
+* We can successfully dial calls from one ThemWi GSM phone to another, with
+  themwi-mncc understanding all dialing formats that are considered standard
+  for cellular phone networks in USA (full international, or 11 digits starting
+  with '1' but no '+', or 10 digits only), as well as our own non-standard
+  shorthand dialing method with only 4 digits;
+
+* Whenever someone dials one of our NANP numbers from the outside world, bulkvs
+  servers send UDP SIP INVITE packets to our server, and by dumping them with
+  our sip-udp-dump utility, we can see exactly what we have to work with;
+
+* The rest remains to be implemented.