sgsn: Add a configuration that is accepted by osmo-sgsn
Provide an exmaple that is accepted by osmo-sgsn.
diff --git a/openbsc/doc/examples/osmo-sgsn/osmo-sgsn.cfg b/openbsc/doc/examples/osmo-sgsn/osmo-sgsn.cfg
new file mode 100644
index 0000000..027c03d
--- /dev/null
+++ b/openbsc/doc/examples/osmo-sgsn/osmo-sgsn.cfg
@@ -0,0 +1,26 @@
+!
+! Osmocom SGSN configuration
+!
+!
+line vty
+ no login
+!
+sgsn
+ gtp local-ip 10.23.23.23
+ ggsn 0 remote-ip 192.168.0.101
+ ggsn 0 gtp-version 1
+!
+ns
+ timer tns-block 3
+ timer tns-block-retries 3
+ timer tns-reset 3
+ timer tns-reset-retries 3
+ timer tns-test 30
+ timer tns-alive 3
+ timer tns-alive-retries 10
+ encapsulation udp local-ip 192.168.0.101
+ encapsulation udp local-port 23000
+ encapsulation framerelay-gre enabled 0
+!
+bssgp
+!