diff --git a/src/gprs_ms.c b/src/gprs_ms.c
index 3ed4244..8453f20 100644
--- a/src/gprs_ms.c
+++ b/src/gprs_ms.c
@@ -419,6 +419,7 @@
 	ms_unref(old_ms);
 }
 
+/* Set/update the MS object TLLI based on knowledge gained from the MS side (Uplink direction) */
 void ms_set_tlli(struct GprsMs *ms, uint32_t tlli)
 {
 	if (tlli == ms->tlli || tlli == ms->new_ul_tlli)
@@ -443,6 +444,7 @@
 	ms->new_ul_tlli = GSM_RESERVED_TMSI;
 }
 
+/* Set/update the MS object TLLI based on knowledge gained from the SGSN side (Downlink direction) */
 bool ms_confirm_tlli(struct GprsMs *ms, uint32_t tlli)
 {
 	if (tlli == ms->tlli || tlli == ms->new_dl_tlli)