diff --git a/library/GTP_CodecPort.ttcn b/library/GTP_CodecPort.ttcn
index 317210e..b516611 100644
--- a/library/GTP_CodecPort.ttcn
+++ b/library/GTP_CodecPort.ttcn
@@ -14,6 +14,7 @@
 	import from IPL4asp_Types all;
 	import from GTPC_Types all;
 	import from GTPU_Types all;
+	import from Misc_Helpers all;
 
 	modulepar {
 		SystemUnderTest mp_pl_SystemUnderTest := SGSN;
@@ -63,6 +64,10 @@
 		out_ud.peer.remName := in_ud.remName;
 		out_ud.peer.remPort := in_ud.remPort;
 		out_ud.gtpc := dec_PDU_GTPC(in_ud.msg, pl_SystemUnderTest := mp_pl_SystemUnderTest);
+		if (lengthof(in_ud.msg) != out_ud.gtpc.lengthf + 8) {
+			Misc_Helpers.f_shutdown(__BFILE__, __LINE__, fail,
+				log2str("Rx GTPv1-C with field length ", out_ud.gtpc.lengthf, " + 8 != exp ", lengthof(in_ud.msg)));
+		}
 	} with { extension "prototype(fast)" };