OsmoPCU: add MSC chart
diff --git a/doc/manuals/gb/gb-startup.msc b/doc/manuals/gb/gb-startup.msc
index e69de29..654a3d7 100644
--- a/doc/manuals/gb/gb-startup.msc
+++ b/doc/manuals/gb/gb-startup.msc
@@ -0,0 +1,24 @@
+msc {
+ hscale="1.2";
+ sgsn [label="SGSN"], pcu [label="PCU"], bts [label="BTS"], bsc [label="BSC"];
+
+ |||;
+ bts box bsc [label="A-bis connection"];
+ pcu <: bts [label="Config. parameters"];
+ pcu rbox pcu [label="listen on UDP socket"];
+ pcu note sgsn [label="send to SGSN UDP (port 23000)"];
+ pcu => sgsn [label="NS RESET"];
+ pcu <= sgsn [label="NS RESET ACK"];
+ ...;
+ pcu => sgsn [label="NS UNBLOCK"];
+ pcu <= sgsn [label="NS UNBLOCK ACK"];
+ pcu box sgsn [label="NS link established"];
+ ...;
+ pcu => sgsn [label="BVC RESET"];
+ pcu <= sgsn [label="BVC RESET ACK"];
+ ...;
+ pcu => sgsn [label="BVC UNBLOCK"];
+ pcu <= sgsn [label="BVC UNBLOCK ACK"];
+ pcu box sgsn [label="BSSGP link established"];
+ |||;
+}