diff -bBru ns-2.28.orig/mac/mac-802_11.cc ns-2.28/mac/mac-802_11.cc
--- ns-2.28.orig/mac/mac-802_11.cc	2005-01-25 23:38:47.000000000 +0100
+++ ns-2.28/mac/mac-802_11.cc	2005-03-11 15:31:11.585235872 +0100
@@ -39,6 +39,7 @@
  *   - Sushmita
  */
 
+#include "tcp.h"
 #include "delay.h"
 #include "connector.h"
 #include "packet.h"
@@ -177,6 +178,7 @@
 	 * to Mac/802_11 variables
 	 */
 	
+	parent->bind("RetransTime_", &RetransTime);
 	parent->bind("RTSThreshold_", &RTSThreshold);
 	parent->bind("ShortRetryLimit_", &ShortRetryLimit);
 	parent->bind("LongRetryLimit_", &LongRetryLimit);
@@ -783,12 +785,15 @@
 			return 0;
 		}
 		setTxState(MAC_SEND);
-		if((u_int32_t)ETHER_ADDR(mh->dh_ra) != MAC_BROADCAST)
+		if((u_int32_t)ETHER_ADDR(mh->dh_ra) != MAC_BROADCAST) {
                         timeout = txtime(pktTx_)
                                 + DSSS_MaxPropagationDelay              // XXX
                                + phymib_.getSIFS()
                                + txtime(phymib_.getACKlen(), basicRate_)
                                + DSSS_MaxPropagationDelay;             // XXX
+			retrans_time=timeout;
+			//printf("retransmision time : %f\n",retrans_time);
+		}
 		else
 			timeout = txtime(pktTx_);
 		break;
@@ -1048,6 +1053,8 @@
 	struct hdr_cmn *ch;
 	struct hdr_mac802_11 *mh;
 	u_int32_t *rcount, thresh;
+	int retrans, rets_mode;
+	double timelost;
 	assert(mhBackoff_.busy() == 0);
 
 	assert(pktTx_);
@@ -1084,6 +1091,14 @@
         }
 
 	(*rcount)++;
+	retrans = *rcount;
+	timelost = retrans * retrans_time;
+	rets_mode =  macmib_.RetransTime;
+
+	if (rets_mode != 0) {
+		HDR_TCP(pktTx_)->rets_ += timelost;
+		//printf("seq : %d - mac rets : %f \n",HDR_TCP(pktTx_)->seqno_,HDR_TCP(pktTx_)->rets_);
+	}
 
 	if(*rcount >= thresh) {
 		/* IEEE Spec section 9.2.3.5 says this should be greater than
diff -bBru ns-2.28.orig/mac/mac-802_11.h ns-2.28/mac/mac-802_11.h
--- ns-2.28.orig/mac/mac-802_11.h	2005-01-19 19:23:28.000000000 +0100
+++ ns-2.28/mac/mac-802_11.h	2005-03-11 15:31:11.585235872 +0100
@@ -205,6 +205,7 @@
 	u_int32_t	FailedCount;	
 	u_int32_t	RTSFailureCount;
 	u_int32_t	ACKFailureCount;
+	int             RetransTime;
  public:
        inline u_int32_t getRTSThreshold() { return(RTSThreshold);}
        inline u_int32_t getShortRetryLimit() { return(ShortRetryLimit);}
@@ -257,6 +258,7 @@
 	void	txHandler(void);
 
 private:
+	double retrans_time;
 	int		command(int argc, const char*const* argv);
 
 	/*
Seulement dans ns-2.28/: TAGS
diff -bBru ns-2.28.orig/tcl/lib/ns-default.tcl ns-2.28/tcl/lib/ns-default.tcl
--- ns-2.28.orig/tcl/lib/ns-default.tcl	2005-01-19 19:23:37.000000000 +0100
+++ ns-2.28/tcl/lib/ns-default.tcl	2005-03-11 15:31:11.736212920 +0100
@@ -673,6 +673,7 @@
  Mac/802_11 set RTSThreshold_  0               ;# bytes
  Mac/802_11 set ShortRetryLimit_       7               ;# retransmittions
  Mac/802_11 set LongRetryLimit_        4               ;# retransmissions
+ Mac/802_11 set RetransTime_ 0           ;# use Mac retransmissions or not
 
 
 
diff -bBru ns-2.28.orig/tcp/tcp.cc ns-2.28/tcp/tcp.cc
--- ns-2.28.orig/tcp/tcp.cc	2005-01-25 23:38:47.000000000 +0100
+++ ns-2.28/tcp/tcp.cc	2005-03-11 15:31:12.192143608 +0100
@@ -632,6 +632,7 @@
 	hdr_ip *iph = hdr_ip::access(p);
 	int databytes = hdr_cmn::access(p)->size();
 	tcph->seqno() = seqno;
+	tcph->rets() = 0;
 	tcph->ts() = Scheduler::instance().clock();
  
 	// Mark packet for diagnosis purposes if we are in Quick-Start Phase
diff -bBru ns-2.28.orig/tcp/tcp.h ns-2.28/tcp/tcp.h
--- ns-2.28.orig/tcp/tcp.h	2005-01-19 19:23:52.000000000 +0100
+++ ns-2.28/tcp/tcp.h	2005-03-11 15:31:12.192143608 +0100
@@ -46,6 +46,7 @@
 	double ts_;             /* time packet generated (at source) */
 	double ts_echo_;        /* the echoed timestamp (originally sent by
 	                           the peer) */
+	double rets_;           /* retransmission time */
 	int seqno_;             /* sequence number */
 	int reason_;            /* reason for a retransmit */
 	int sack_area_[NSA+1][2];	/* sack blocks: start, end of block */
@@ -66,6 +67,7 @@
 	/* per-field member functions */
 	double& ts() { return (ts_); }
 	double& ts_echo() { return (ts_echo_); }
+	double& rets() { return (rets_); }
 	int& seqno() { return (seqno_); }
 	int& reason() { return (reason_); }
 	int& sa_left(int n) { return (sack_area_[n][0]); }
diff -bBru ns-2.28.orig/tcp/tcp-sink.cc ns-2.28/tcp/tcp-sink.cc
--- ns-2.28.orig/tcp/tcp-sink.cc	2005-01-25 23:38:47.000000000 +0100
+++ ns-2.28/tcp/tcp-sink.cc	2005-03-11 15:31:12.191143760 +0100
@@ -293,6 +293,10 @@
 	ntcp->ts() = now;
 	// timestamp the packet
 
+	ntcp->rets() = otcp->rets_;
+	//printf("seq : %d - ack rets : %f\n",otcp->seqno_,otcp->rets_);
+	// echo the original's retransmission time
+
 	if (ts_echo_bugfix_)  /* TCP/IP Illustrated, Vol. 2, pg. 870 */
 		ntcp->ts_echo() = acker_->ts_to_echo();
 	else
diff -bBru ns-2.28.orig/tcp/tcp-vegas.cc ns-2.28/tcp/tcp-vegas.cc
--- ns-2.28.orig/tcp/tcp-vegas.cc	2005-01-25 23:38:47.000000000 +0100
+++ ns-2.28/tcp/tcp-vegas.cc	2005-03-11 15:31:12.191143760 +0100
@@ -182,7 +182,7 @@
			if(v_cntRTT_ > 0)
 				rtt = v_sumRTT_ / v_cntRTT_;
			else 
-				rtt = currentTime - v_begtime_;
+				rtt = currentTime - v_begtime_ - tcph->rets_;
 
 			v_sumRTT_ = 0.0;
 			v_cntRTT_ = 0;
@@ -285,7 +285,7 @@
 		if((sendTime !=0.) && (transmits==1)) {
 			 // update fine-grained timeout value, v_timeout_.
 			double rtt, n;
-			rtt = currentTime - sendTime;
+			rtt = currentTime - sendTime - tcph->rets_;
 			v_sumRTT_ += rtt;
 			++v_cntRTT_;
 			if(rtt>0) {