diff --git a/core/plug-in/sipctrl/trans_layer.cpp b/core/plug-in/sipctrl/trans_layer.cpp
index 916a4228..8d59d8c1 100644
--- a/core/plug-in/sipctrl/trans_layer.cpp
+++ b/core/plug-in/sipctrl/trans_layer.cpp
@@ -812,6 +812,13 @@ int trans_layer::update_uas_reply(trans_bucket* bucket, sip_trans* t, int reply_
 	    //bucket->remove_trans(t);
 	    //return TS_TERMINATED;
 
+	    //
+	    // In this stack, the transaction layer
+	    // takes care of re-transmiting the 200 reply
+	    // in a UAS INVITE transaction. The core above
+	    // is commented out and shows the behavior as
+	    // required by the RFC.
+	    //
 	    t->state = TS_TERMINATED_200;
 	    t->reset_timer(STIMER_G,G_TIMER,bucket->get_id());
 	    t->reset_timer(STIMER_H,H_TIMER,bucket->get_id());
@@ -819,8 +826,9 @@ int trans_layer::update_uas_reply(trans_bucket* bucket, sip_trans* t, int reply_
 	}
 	else {
 	    t->state = TS_COMPLETED;
-	    //TODO: set J timer
-	    t->reset_timer(STIMER_J,J_TIMER,bucket->get_id()); // 0 if !UDP
+	    // TODO: set J timer
+	    //  0 if !UDP
+	    t->reset_timer(STIMER_J,J_TIMER,bucket->get_id()); 
 	}
     }
     else {
@@ -843,11 +851,9 @@ int trans_layer::update_uas_request(trans_bucket* bucket, sip_trans* t, sip_msg*
     case TS_COMPLETED:
 	t->state = TS_CONFIRMED;
 
-	// TODO: remove G and H timer.
 	t->clear_timer(STIMER_G);
 	t->clear_timer(STIMER_H);
 
-	// TODO: set I timer.
 	t->reset_timer(STIMER_I,I_TIMER,bucket->get_id());
 	
 	// drop through
@@ -1071,16 +1077,21 @@ void trans_layer::timer_expired(timer* t, trans_bucket* bucket, sip_trans* tr)
     case STIMER_E:  // Trying/Proceeding: (re-)send request
     case STIMER_G:  // Completed: (re-)send response
 
-	n++;
-	
+	n++; // re-transmission counter
+
+	//
+	// in this stack, the transaction layer
+	// takes care of re-transmiting the 200 reply
+	// in a UAS INVITE transaction.
+	//
 	if(tr->state == TS_TERMINATED_200){
 	    
-	    // Retransmit reply to INV
+	    // re-transmit reply to INV
 	    retransmit(tr);
 	}
 	else {
 
-	    // Retransmit request
+	    // re-transmit request
 	    retransmit(tr->msg);
 	}