diff --git a/library/RAN_Emulation.ttcnpp b/library/RAN_Emulation.ttcnpp
index e6d36e6..3198ee1 100644
--- a/library/RAN_Emulation.ttcnpp
+++ b/library/RAN_Emulation.ttcnpp
@@ -1254,7 +1254,10 @@
 			f_create_imsi(imsi, tmsi, vc_hdlr);
 			PROC.reply(RAN_register_imsi:{imsi, tmsi, vc_hdlr}) to vc_hdlr;
 			}
-
+		[] PROC.getcall(RAN_unregister_imsi:{?,?}) -> param(imsi, vc_hdlr) {
+			f_destroy_imsi(imsi, vc_hdlr);
+			PROC.reply(RAN_unregister_imsi:{imsi, vc_hdlr}) to vc_hdlr;
+			}
 
 		}
 	}
@@ -1287,6 +1290,7 @@
 
 /* procedure based port to register for incoming IMSI/TMSI */
 signature RAN_register_imsi(in hexstring imsi, in OCT4 tmsi, in RAN_ConnHdlr hdlr);
+signature RAN_unregister_imsi(in hexstring imsi, in RAN_ConnHdlr hdlr);
 
 /* If DTAP happens across other channels (e.g. GSUP), provide manual advancing of the n_sd sequence number */
 signature RAN_last_n_sd(in RAN_ConnHdlr hdlr, out N_Sd_Array last_n_sd);
@@ -1295,7 +1299,7 @@
 signature RAN_continue_after_n_sd(N_Sd_Array last_n_sd, in RAN_ConnHdlr hdlr);
 
 type port RAN_PROC_PT procedure {
-	inout RAN_register, RAN_register_imsi, RAN_register_handoverRequest, RAN_last_n_sd, RAN_continue_after_n_sd;
+	inout RAN_register, RAN_register_imsi, RAN_unregister_imsi, RAN_register_handoverRequest, RAN_last_n_sd, RAN_continue_after_n_sd;
 } with { extension "internal" };
 
 #ifdef RAN_EMULATION_BSSAP
@@ -1425,6 +1429,19 @@
 	testcase.stop("No space left in ImsiTable");
 }
 
+private function f_destroy_imsi(hexstring imsi, RAN_ConnHdlr hdlr)
+runs on RAN_Emulation_CT {
+	for (var integer i := 0; i < sizeof(ImsiTable); i := i+1) {
+		if (ImsiTable[i].imsi == imsi and ImsiTable[i].comp_ref == hdlr) {
+			ImsiTable[i].comp_ref := null;
+			ImsiTable[i].imsi := omit;
+			ImsiTable[i].tmsi := 'FFFFFFFF'O;
+			log("Removed IMSI[", i, "] for ", imsi, " to be handled at ", hdlr);
+			return;
+		}
+	}
+	testcase.stop("Unable to find to-be-destroyed IMSI in ImsiTable");
+}
 
 private function f_expect_table_init()
 runs on RAN_Emulation_CT {
@@ -1451,6 +1468,15 @@
 	}
 }
 
+/* helper function for clients to register their IMSI/TMSI */
+function f_ran_unregister_imsi(hexstring imsi)
+runs on RAN_ConnHdlr {
+
+	BSSAP_PROC.call(RAN_unregister_imsi:{imsi, self}) {
+		[] BSSAP_PROC.getreply(RAN_unregister_imsi:{?,?}) {};
+	}
+}
+
 /* register an expect with the BSSMAP core */
 function f_ran_register_exp(octetstring l3_enc) runs on RAN_ConnHdlr {
 	BSSAP_PROC.call(RAN_register:{l3_enc, self}) {