diff --git a/include/osmocore/gsm0808.h b/include/osmocore/gsm0808.h
index 9166e54..82f17ca 100644
--- a/include/osmocore/gsm0808.h
+++ b/include/osmocore/gsm0808.h
@@ -24,7 +24,7 @@
 
 struct msgb;
 
-struct msgb *gsm0808_create_layer3(struct msgb *msg, uint16_t netcode, uint16_t countrycode, int lac, int ci);
+struct msgb *gsm0808_create_layer3(struct msgb *msg, uint16_t netcode, uint16_t countrycode, int lac, uint16_t ci);
 struct msgb *gsm0808_create_reset(void);
 struct msgb *gsm0808_create_clear_complete(void);
 struct msgb *gsm0808_create_cipher_complete(struct msgb *layer3, uint8_t alg_id);