diff --git a/core/sip/trans_layer.cpp b/core/sip/trans_layer.cpp
index bd584bce..3cd8aa9a 100644
--- a/core/sip/trans_layer.cpp
+++ b/core/sip/trans_layer.cpp
@@ -1105,7 +1105,7 @@ void _trans_layer::received_msg(sip_msg* msg)
     switch(msg->type){
     case SIP_REQUEST: 
 	
-	if((t = bucket->match_request(msg)) != NULL){
+	if((t = bucket->match_request(msg,TT_UAS)) != NULL){
 	    if(msg->u.request->method != t->msg->u.request->method){
 		
 		// ACK matched INVITE transaction
@@ -1416,7 +1416,7 @@ int _trans_layer::update_uac_request(trans_bucket* bucket, sip_trans*& t, sip_ms
     }
     else {
 	// 200 ACK
-	t = bucket->match_request(msg);
+	t = bucket->match_request(msg,TT_UAC);
 	if(t == NULL){
 	    DBG("While sending 200 ACK: no matching transaction\n");
 	    return -1;
diff --git a/core/sip/trans_table.cpp b/core/sip/trans_table.cpp
index 4ac6be48..f1442fdb 100644
--- a/core/sip/trans_table.cpp
+++ b/core/sip/trans_table.cpp
@@ -57,7 +57,7 @@ trans_bucket::~trans_bucket()
 {
 }
 
-sip_trans* trans_bucket::match_request(sip_msg* msg)
+sip_trans* trans_bucket::match_request(sip_msg* msg, unsigned int ttype)
 {
     // assert(msg && msg->cseq && msg->callid);
     // sip_cseq* cseq  = dynamic_cast<sip_cseq*>(msg->cseq->p);
@@ -93,7 +93,8 @@ sip_trans* trans_bucket::match_request(sip_msg* msg)
 	trans_list::iterator it = elmts.begin();
 	for(;it!=elmts.end();++it) {
 	    
-	    if( (*it)->msg->type != SIP_REQUEST ){
+	    if( ((*it)->msg->type != SIP_REQUEST) ||
+		((*it)->type != ttype)){
 		continue;
 	    }
 
@@ -168,10 +169,11 @@ sip_trans* trans_bucket::match_request(sip_msg* msg)
 	    // Cseq (number only)
 	    // top Via
 	    // + To-tag of reply
-	    
-	    if( ((*it)->type != TT_UAS) || 
-		((*it)->msg->type != SIP_REQUEST))
+
+	    if( ((*it)->msg->type != SIP_REQUEST) ||
+		((*it)->type != ttype)){
 		continue;
+	    }
 
 	    if( (msg->u.request->method != (*it)->msg->u.request->method) &&
 		( (msg->u.request->method != sip_request::ACK) ||
@@ -394,7 +396,7 @@ sip_trans* trans_bucket::match_1xx_prack(sip_msg* msg)
     return NULL;
 }
 
-sip_trans* trans_bucket::add_trans(sip_msg* msg, int ttype)
+sip_trans* trans_bucket::add_trans(sip_msg* msg, unsigned int ttype)
 {
     sip_trans* t = new sip_trans();
 
diff --git a/core/sip/trans_table.h b/core/sip/trans_table.h
index 1c2e0ea7..95b197e8 100644
--- a/core/sip/trans_table.h
+++ b/core/sip/trans_table.h
@@ -20,9 +20,9 @@ public:
     typedef ht_bucket<sip_trans>::value_list trans_list;
 
     
-    // Match a request to UAS transactions
+    // Match a request to UAS/UAC transactions
     // in this bucket
-    sip_trans* match_request(sip_msg* msg);
+    sip_trans* match_request(sip_msg* msg, unsigned int ttype);
 
     // Match a PRACK request against transactions
     // in this bucket
@@ -32,7 +32,7 @@ public:
     // in this bucket
     sip_trans* match_reply(sip_msg* msg);
 
-    sip_trans* add_trans(sip_msg* msg, int ttype);
+    sip_trans* add_trans(sip_msg* msg, unsigned int ttype);
 
 private:
     sip_trans* match_200_ack(sip_trans* t,sip_msg* msg);