diff --git a/include/osmocom/msc/osmux.h b/include/osmocom/msc/osmux.h
new file mode 100644
index 0000000..7af32fc
--- /dev/null
+++ b/include/osmocom/msc/osmux.h
@@ -0,0 +1,11 @@
+#pragma once
+
+enum osmux_usage {
+	/* MSC won't use Osmux in call legs towards its RAN */
+	OSMUX_USAGE_OFF = 0,
+	/* MSC will use Osmux in call legs towards RAN as long as RAN announced support for it */
+	OSMUX_USAGE_ON = 1,
+	/* MSC will always use Osmux in call legs towards its RAN, and will
+	   reject calls for RANs which didn't announce support for it */
+	OSMUX_USAGE_ONLY = 2,
+};