diff --git a/library/SIP_Templates.ttcn b/library/SIP_Templates.ttcn
index be07196..e115bb7 100644
--- a/library/SIP_Templates.ttcn
+++ b/library/SIP_Templates.ttcn
@@ -3,6 +3,7 @@
 import from SIPmsg_Types all;
 import from TCCConversion_Functions all;
 import from TCCOpenSecurity_Functions all;
+import from TCCDateTime_Functions all;
 import from Native_Functions all;
 import from Osmocom_Types all;
 import from Misc_Helpers all;
@@ -1151,10 +1152,12 @@
 	req.msgHeader.cSeq.seqNumber := f_sip_next_seq_nr(valueof(req.msgHeader.cSeq.seqNumber));
 }
 
-/* Tags shall have at least 32 bit of randomness */
 function f_sip_rand_tag() return charstring {
+	/* Tags shall have at least 32 bit of randomness */
 	var integer rnd_int := f_rnd_int(4294967296);
-	return hex2str(int2hex(rnd_int, 8));
+	/* Make collisions harder by appending time to the final string: */
+	var integer ts_int := f_time_ms() mod 4294967296;
+	return hex2str(int2hex(rnd_int, 8)) & "-" & hex2str(int2hex(ts_int, 8));
 }
 
 /* Generate a "branch" tag value.