move openbsc/* to repos root

This is the first step in creating this repository from the legacy openbsc.git.

Like all other Osmocom repositories, keep the autoconf and automake files in
the repository root. openbsc.git has been the sole exception, which ends now.

Change-Id: I9c6f2a448d9cb1cc088cf1cf6918b69d7e69b4e7

1 files changed, 25 insertions, 0 deletions

diff --git a/doc/call-routing.txt b/doc/call-routing.txt
new file mode 100644
index 000000000..3402f9e33
--- /dev/null
+++ b/doc/call-routing.txt
@@ -0,0 +1,25 @@
+Call routing in OpenBSC
+
+Flow of events:
+
+ # MO call initiated by MS, CHANNEL RQD, IMMEDIATE ASSIGN
+ # MS sends CC SETUP message, we assume already on TCH/H FACCH
+ # OpenBSC does a subscriber lookup based on the target extension
+  * If a subscriber is found:
+   # send CALL PROCEEDING message to MO
+   # page the MT subscriber and ask itI to ask for TCH/H
+   # once paging completes, we have the TCH/H for the MT end
+   # send SETUP to MT
+   # receive CALL CONFIRMED from MT
+   # set-up the TRAU mux mapping between the E1 subslots for both TCH/H
+   # receive ALERTING from MT, route ALERTING to MO
+   # receive CONNECT from MT, confirm to MT with CONNECT_ACK
+   # send a CONNECT message to MO, receive CONNECT_ACK from MO
+ * If subscriber is not found:
+  # send RELEASE COMPLETE with apropriate cause to MO (1: unalloacated 3: no route)
+  
+
+
+Thoughts about RR/MM:
+
+* we allocate RR/MM entities on demand, when we need them