diff --git a/include/osmocom/gprs/gprs_ns2.h b/include/osmocom/gprs/gprs_ns2.h
index cbd6647..d798ac4 100644
--- a/include/osmocom/gprs/gprs_ns2.h
+++ b/include/osmocom/gprs/gprs_ns2.h
@@ -99,6 +99,7 @@
 
 struct gprs_ns2_nse *gprs_ns2_nse_by_nsei(struct gprs_ns2_inst *nsi, uint16_t nsei);
 struct gprs_ns2_nse *gprs_ns2_create_nse(struct gprs_ns2_inst *nsi, uint16_t nsei);
+uint16_t gprs_ns2_nse_nsei(struct gprs_ns2_nse *nse);
 void gprs_ns2_free_nse(struct gprs_ns2_nse *nse);
 
 /* create vc */