diff --git a/ggsn/ggsn.c b/ggsn/ggsn.c
index 05a56ae..c6a6dac 100644
--- a/ggsn/ggsn.c
+++ b/ggsn/ggsn.c
@@ -146,7 +146,7 @@
 
 	const char *addrstr = in46a_ntop(&member->addr, addrbuf, sizeof(addrbuf));
 
-	snprintf(val, sizeof(val), "%" PRIu64 ",%s", pdp->imsi, addrstr);
+	snprintf(val, sizeof(val), "%s,%s", imsi_gtp2str(&pdp->imsi), addrstr);
 
 	if (ctrl_cmd_send_trap(gsn->ctrl, var, val) < 0) {
 		LOGP(DGGSN, LOGL_ERROR, "Failed to create and send TRAP for IMSI %" PRIu64 " [%s].\n", pdp->imsi, var);